Provided by: remind_04.03.01-1build1_amd64 bug

NAME

       remind - a sophisticated reminder service

SYNOPSIS

       remind [options] filename [date] [*rep] [time]

DESCRIPTION

       Remind  reads  the  supplied filename and executes the commands found in it.  The commands
       are used to issue reminders and alarms.  Each reminder or alarm can consist of  a  message
       sent to standard output, or a program to be executed.

       If  filename  is specified as a single dash '-', then Remind takes its input from standard
       input.  This also implicitly enables the -o option, described below.

       If filename happens to be a directory rather than a plain file, then Remind reads  all  of
       the  files in that directory that match the pattern "*.rem".  The files are read in sorted
       order; the sort order may depend on your locale, but should match the sort order  used  by
       the shell to expand "*.rem".

       Remind  reads  its  files starting from the beginning to the end, or until it encounters a
       line whose sole content is "__EOF__" (without the quotes.)   Anything  after  the  __EOF__
       marker is completely ignored.

OPTIONS

       Remind  has a slew of options.  If you're new to the program, ignore them for now and skip
       to the section "REMINDER FILES".

       --version
              The --version option causes Remind to print its version number to  standard  output
              and then exit.

       -n     The  -n  option  causes  Remind  to print the next occurrence of each reminder in a
              simple calendar format.  You can sort this by date by  piping  the  output  through
              sort(1).  Note that the -n option causes any -g option to be ignored.

       -j[n]  Runs Remind in "purge" mode to get rid of expired reminders.  See the section PURGE
              MODE for details.

       -r     The -r option disables RUN directives and the shell() function.

       -c[flags]n
              The -c option causes Remind to produce a calendar that is sent to standard  output.
              If  you supply a number n, then a calendar will be generated for n months, starting
              with the current month.  By default, a calendar  for  only  the  current  month  is
              produced.

              You can precede n (if any) with a set of flags.  The flags are as follows:

              '+'    causes a calendar for n weeks to be produced.

              'a'    causes  Remind to display reminders on the calendar on the day they actually
                     occur as well as on any preceding days specified by  the  reminder's  delta.
                     This also causes Remind to include text outside %"...%" sequences that would
                     otherwise be removed (though the actual %" markers themselves are removed.)

              'l'    causes Remind to use VT100 line-drawing characters  to  draw  the  calendar.
                     The  characters  are hard-coded and will only work on terminals that emulate
                     the VT00 line-drawing character set.

              'u'    is similar to 'l', but causes Remind to use UNICODE line-drawing  characters
                     to  draw  the calendar.  The characters are hard-coded and will only work on
                     terminals that are set to UTF-8 character encoding.  This flag also  enables
                     the  use  of  the  UNICODE  "left-to-right"  mark that can fix up formatting
                     problems with right-to-left languages in the calendar display.

              'c'    causes Remind to use VT100 escape sequences  to  approximate  SPECIAL  COLOR
                     reminders.   Note  that  this  flag is kept for backwards-compatibility; you
                     should use the -@[n][,m][,b] command-line option instead.

       -@[n][,m][,b]
              Tells Remind to approximate SPECIAL COLOR and SHADE reminders  using  VT100  escape
              sequences.  The approximation is (of necessity) very coarse, because the VT100 only
              has eight different color sequences, each with one of two  brightnesses.   A  color
              component  greater  than  64  is  considered  "on",  and  if any of the three color
              components is greater than 128, the color is considered "bright".

              If you supply the optional numeric parameters, the  have  the  following  meanings:
              n=0  tells  Remind  to  use  the  standard 16 VT100 colors.  n=1 tells it to use an
              extended 256-color palette supported by many terminal emulators such as xterm.  And
              n=2  tells  it  to  use  escape  sequences  that  support true 24-bit colors, again
              supported by many terminal emulators such as xterm.

              If the optional m parameter is supplied following a comma, then  m=0  tells  Remind
              that  the  terminal  background is dark, and Remind will brighten up dark colors to
              make them visible.  If m=1, then Remind assumes the terminal  background  is  light
              and  it  will  darken  bright colors to make them visible.  If m is specified as 2,
              then Remind does not perform any adjustments, and some reminders  may  be  hard  or
              impossible  to  see if the color is too close to the terminal background color.  If
              you supply the letter t rather than a number, then Remind  attempts  to  guess  the
              background color of the terminal, even if stdout is not a terminal.

              On  startup,  if the standard output is a terminal, Remind attempts to determine if
              the terminal background is dark or light by sending a special  escape  sequence  to
              determine  the background color.  The m parameter can override this check (or force
              it if m is given as t.)

              If the optional b parameter is supplied following a comma, then b=0 tells Remind to
              ignore  SPECIAL  SHADE  reminders  (the  default)  and  b=1 tells Remind to respect
              SPECIAL SHADE reminders by emitting VT100 escape codes to color the  background  of
              the  calendar  cell.   Note  that SHADE does not work well unless you are using the
              extended 256-color palette (n=1) or the true 24-bit colors (n=2).   Note  that  for
              calendar cells that are shaded, the clamping mechanism described earlier for m=0 or
              m=1 is skipped; it is assumed that if you  set  both  the  foreground  color  of  a
              reminder and the background color of a cell, then you know what you are doing.

       -wcol[,pad[,spc]]]
              The  -w  option  specifies  the  output width, padding and spacing of the formatted
              calendar output.  Col specifies the number of columns in the output device.  If col
              is  not  specified,  or  is  specified as 0, it defaults to the larger of 71 or the
              actual width of your terminal, or to 80 if standard output is not a  terminal.   If
              col  is  specified  as  the  letter t, then Remind attempts to get the width of the
              /dev/tty terminal device.  This is useful, for example, if you pipe calendar output
              into less; even though standard output is a pipe, you want the calendar to be sized
              correctly for your terminal window:

                      remind -c -wt .reminders | less

              Note that the value of col is also used to  set  the  system  variable  $FormWidth,
              which is initialized to col - 8.  See "SYSTEM VARIABLES" for details.

              Pad  specifies  how many lines to use to "pad" empty calendar boxes.  This defaults
              to 5.  If you have many reminders on certain days that make your calendar too large
              to  fit  on  a page, you can try reducing pad to make the empty boxes smaller.  Spc
              specifies how many blank lines to leave  between  the  day  number  and  the  first
              reminder entry.  It defaults to 1.

              Any  of col, pad or spc can be omitted, providing you provide the correct number of
              commas.  Don't use any spaces in the option.

       -s[a]n The -s option is very similar to the -c option, except that the output calendar  is
              not  formatted.   It  is  listed in a "simple format" that can be used as input for
              more sophisticated calendar-drawing programs.  If n starts with  "+",  then  it  is
              interpreted as a number of weeks.

              If  you  immediately follow the s with the letter a, then Remind displays reminders
              on the calendar on the day they actually occur as well as  on  any  preceding  days
              specified by the reminder's delta.

       -p[a][p][p][q]n
              The  -p  option  is  very similar to the -s option, except that the output contains
              additional information for use by the Rem2PS program, which  creates  a  PostScript
              calendar,  and  various  other  back-end programs.  For this option, n cannot start
              with "+"; it must specify a number of months.  The  format  of  the  -p  output  is
              described  in  the  rem2ps(1)  man  page.  If you immediately follow the p with the
              letter a, then Remind displays reminders on the calendar on the day  they  actually
              occur  as  well as on any preceding days specified by the reminder's delta.  If you
              follow the p with another p, then  Remind  uses  a  more  comprehensive  JSON-based
              format rather than the "simple calendar" format.  This format is also documented in
              the rem2ps(1) man page.  Finally, if you use three p's, as  in  -ppp,  then  Remind
              uses  a pure JSON format, again documented in rem2ps(1).  If you include a q letter
              with this option, then the normal calendar-mode substitution filter is disabled and
              the %"...%" sequences are preserved in the output.

              Note that the -pp or -ppp options also enable the -l option.

       -l     If  you  use  the  -l option in conjunction with the -p option, then Remind outputs
              additional information for back-end  programs  such  as  rem2ps.   This  additional
              information  lets  the  back-end programs correlate a reminder with the source file
              and line number that produced it.

       -m     The -m option causes the -c or -p options to produce a calendar whose first  column
              is Monday rather than Sunday.  (This conforms to the international standard.)

       -v     The  -v  option  makes the output of Remind slightly more verbose.  Currently, this
              causes Remind to echo a bad line in case of an  error,  and  to  print  a  security
              message if a script tests the $RunOff system variable.

       -o     The -o option causes Remind to ignore all ONCE directives.

       -t     The -t option causes Remind to trigger all non-expired reminders, regardless of the
              delta supplied for each reminder.

       -tn    If you supply a number n after the -t option, then Remind pretends  that  echo  REM
              command has a delta of ++n, regardless of any existing delta.

       -tz    If  you  supply  the  letter  z  after  the  -t  option,  then  Remind sets all REM
              statements' deltas to zero, regardless of the value supplied in the  REM  statement
              itself.  In effect, this disables all deltas of the form +n and ++n.

       -tt[n] The  -tt  option causes Remind to assume a default delta of n minutes for all timed
              reminders.  If -tt is given with no n, a default delta of 5 minutes is used.

       -h     The -h option ("hush...") suppresses certain warning and information messages.   In
              particular, if no reminders are triggered, this mode produces no output.

       -a     The -a option causes Remind not to immediately trigger timed reminders that trigger
              on the current day.  It also causes Remind  not  to  place  timed  reminders  in  a
              calendar.   If  you  supply  two or more -a options, then Remind will trigger timed
              reminders that are in the future, but will not trigger timed reminders  whose  time
              has passed.  (Regardless of how many -a options you supply, Remind will not include
              timed reminders in the calendar if at least one -a option is used.)

       -q     The -q option causes Remind not to queue timed reminders for later execution.

       -f     The -f option causes Remind to remain in  the  foreground  when  processing  queued
              reminders, rather than forking off a background process to handle them.

       -e     The  -e  option diverts error messages (normally sent to the standard error stream)
              to the standard output stream.

       -dchars
              The -d option enables certain debugging modes.  The chars specify  which  modes  to
              enable:

         e      Echo all input lines

         x      Trace all expression evaluation

         t      Display all trigger date computation

         v      Dump the variable table after execution of the reminder script

         l      Echo lines when displaying error messages

         f      Trace the reading of reminder files

       -g[a|d[a|d[a|d[a|d]]]]
              Normally,  reminders  are  issued in the order in which they are encountered in the
              reminder script.  The -g option cause Remind to sort reminders  by  date  and  time
              prior  to  issuing  them.   The  optional a and d characters specify the sort order
              (ascending or descending) for the date, time and priority fields.  See the  section
              "SORTING REMINDERS" for more information.

              Note that -g is ignored if you use the -n option.

       -b[n]  Set the time format for the calendar and simple-calendar outputs.  N can range from
              0 to 2, with the default 0.  A value of 0 causes times to be  inserted  in  12-hour
              (am/pm)  format.   1  causes times to be inserted in 24-hour format, and 2 inhibits
              the automatic insertion of times in the calendar output.

       -x[n]  Sets the iteration limit for the SATISFY clause of  a  REM  command.   Defaults  to
              1000.

       -kcmd  Instead of simply printing MSG-type reminders, this causes them to be passed to the
              specific cmd.  You must use '%s' where you want the body to appear, and may need to
              enclose  this  option in quotes.  Note that all shell characters in the body of the
              reminder are escaped with a backslash, and the  entire  body  of  the  reminder  is
              passed as a single argument.  Note that this option overrides the -r option and the
              RUN OFF command.

              As an example, suppose you have an X Window program called xmessage that pops up  a
              window and displays its invocation arguments.  You could use:

                        remind '-kxmessage %s &' ...

              to have all of your MSG-type reminders processed using xmessage.

              A  word  of warning: It is very easy to spawn dozens of xmessage processes with the
              above technique.  So be very careful.  Because all shell and whitespace  characters
              are  escaped, the program you execute with the -k option must be prepared to handle
              the entire message as a single argument.

              If you follow the -k option with a colon, then  the  command  is  applied  only  to
              queued  timed  reminders.   Normal  reminders  are  handled as usual.  In the above
              example, if you want normal reminders to simply be displayed as usual,  but  queued
              reminders to be sent to notify-send, you could use:

                        remind '-k:notify-send %s &' ...

              You  use  both  -kcmd1 and -k:cmd2 to use different commands for queued versus non-
              queued reminders.

       -z[n] Runs Remind in the daemon mode.  If n
              is supplied, it specifies how often (in minutes) Remind should wake up to check  if
              the reminder script has been changed.  N defaults to 1, and can range from 1 to 60.
              Note that the use of the -z option also enables the -f option.

              If you supply the option -zj, Remind runs in a special  mode  called  server  mode.
              This  is  documented  in  the tkremind man page; see tkremind(1).  The older server
              mode option -z0 still works, but  is  deprecated;  it  uses  an  ad-hoc  method  to
              communicate with the client rather than using JSON to communicate with the client.

       -uname Runs Remind with the uid and gid of the user specified by name.  The option changes
              the uid and gid as described, and sets the environment variables  HOME,  SHELL  and
              USER  to  the  home directory, shell, and user name, respectively, of the specified
              user.  LOGNAME is also set to the specified user name.  This option  is  meant  for
              use  in  shell  scripts  that  mail reminders to all users.  Note that as of Remind
              3.00.17, using -u implies -r  --  the  RUN  directive  and  shell()  functions  are
              disabled.   However, if you prefix name with a +-sign, then RUN and shell() are not
              disabled.  That is, -uwhatever switches the user  to  whatever  and  disables  RUN,
              whereas -u+whatever switches the user to whatever but leaves RUN enabled.

              Non-root  users can also use the -u option.  However, in this case, it only changes
              the environment variables as described above.  It does not change the effective uid
              or gid.

       -+username
              Causes Remind to trust files owned by the user username.  Normally, if Remind reads
              a file that you do not own, it disables RUN and the shell() function.  This  option
              causes  it  to  also  trust  files  owned  by username.  You can supply multiple -+
              options to trust multiple users, up to a limit of 20 trusted users.

       -y     Causes Remind to synthesize a tag for any reminder that lacks a TAG clause.

       -ivar=expr
              Sets the value of the specified var to expr, and preserves var.  Expr  can  be  any
              valid  Remind  expression.   See the section "INITIALIZING VARIABLES ON THE COMMAND
              LINE" for more details.

       -ifunc(args)=definition
              Allows you to define a function on the command line.

       If you supply a date on the command line, it must consist of day month year, where day  is
       the day of the month, month is at least the first three letters of the English name of the
       month, and year is a year (all 4 digits) from 1990 to about 2075.  You can leave  out  the
       day, which then defaults to 1.

       If  you  do supply a date on the command line, then Remind uses it, rather than the actual
       system date, as its notion of "today."  This lets you create calendars for future  months,
       or  test  to  see  how your reminders will be triggered in the future.  Similarly, you can
       supply a time to set Remind's notion of "now" to a particular time.  Supplying a  time  on
       the  command  line  also implicitly enables the -q option and disables the -z option.  The
       time may be specified in 24-hour format (eg, 13:20) or common "AM/PM" format (1:20pm).

       If you would rather specify the date more succinctly, you can supply it as  YYYY-MM-DD  or
       YYYY/MM/DD.   You  can  even  supply  a date and time on the command line as one argument:
       YYYY-MM-DD@HH:MM.

       In addition, you can supply a repeat parameter, which has  the  form  *rep.   This  causes
       Remind to be run rep times, with the date incrementing on each iteration.  You may have to
       enclose the parameter in quotes to avoid shell expansion.  See  the  subsection  "Repeated
       Execution" in the section "CALENDAR MODE" for more information.

REMINDER FILES

       Remind  uses  scripts  to  control  its operation.  You can use any text editor capable of
       creating plain-text files to create a Remind script.  The commands  inside  a  script  can
       range from the very simple and almost immediately understandable:

            REM 6 Jan MSG Dianne's birthday

       to the baroque and obscure:

            REM [date(thisyear, 1, 1) + 180] ++5 OMIT \
            sat sun BEFORE MSG [ord(thisyear-1980)] payment due %b!

       A  reminder  file  consists  of commands, with one command per line.  Several lines can be
       continued using the backslash character, as in the above example.  In this  case,  all  of
       the  concatenated  lines  are  treated  as a single line by Remind.  Note that if an error
       occurs, Remind reports the line number of the last line of a continued line.

       Remind ignores blank lines, and lines beginning with the '#' or ';' characters.   You  can
       use the semicolon as a comment character if you wish to pass a Remind script through the C
       pre-processor, which interprets the  '#'  character  as  the  start  of  a  pre-processing
       directive.

       Note that Remind processes line continuations before anything else.  For example:

            # This is a comment \
            This line is part of the comment because of line continuation \
            and so on.
            REM MSG This line is not ignored (no \ above)

       Remind  is  not  case sensitive; you can generally use any mixture of upper- or lower-case
       for commands, parameters, invocation options, etc.

THE REM COMMAND

       The most powerful command in a  Remind  script  is  the  REM  command.   This  command  is
       responsible for issuing reminders.  Its syntax is:

              REM  [ONCE]  [date_spec]  [back]  [delta] [repeat] [PRIORITY prio] [SKIP | BEFORE |
              AFTER] [OMIT omit_list]  [ADDOMIT]  [NOQUEUE]  [OMITFUNC  omit_function]  [AT  time
              [tdelta]  [trepeat]] [SCHED sched_function] [WARN warn_function] [UNTIL expiry_date
              | THROUGH last_date] [SCANFROM scan_date |  FROM  start_date]  [DURATION  duration]
              [TAG tag] <MSG | MSF | RUN | CAL | SATISFY | SPECIAL special | PS | PSFILE> body

       The parts of the REM command can be specified in any order, except that the body must come
       immediately after the MSG, RUN, CAL, PS, PSFILE or SATISFY keyword.

       The REM token is optional, providing that the remainder of the command cannot be  mistaken
       for another Remind command such as OMIT or RUN.  The portion of the REM command before the
       MSG, MSF RUN, CAL or SATISFY clause is called a trigger.

       MSG, MSF, RUN, CAL, SPECIAL, PS and PSFILE

       These keywords denote the type of the reminder.  (SATISFY is more complicated and will  be
       explained  later.)   A MSG-type reminder normally prints a message to the standard output,
       after passing the body through a special substitution filter,  described  in  the  section
       "THE  SUBSTITUTION  FILTER."   However,  if you have used the -k command-line option, then
       MSG-type reminders are passed to the appropriate program.  Note that the options  -c,  -s,
       -p and -n disable the -k option.

       Note  that  you  can omit the reminder type, in which case it defaults to MSG.  So you can
       write:

            6 January Dianne's Birthday

       although this is not recommended.

       The MSF keyword is almost the same as  the  MSG  keyword,  except  that  the  reminder  is
       formatted  to  fit  into  a  paragraph-like  format.   Three  system variables control the
       formatting of MSF-type reminders - they  are  $FirstIndent,  $SubsIndent  and  $FormWidth.
       They  are discussed in the section "SYSTEM VARIABLES."  The MSF keyword causes the spacing
       of your reminder to be altered - extra spaces are discarded, and  two  spaces  are  placed
       after  periods  and  other  characters,  as specified by the system variables $EndSent and
       $EndSentIg.  Note that if the body of the reminder  includes  newline  characters  (placed
       there  with  the  %_  sequence),  then  the  newlines are treated as the beginnings of new
       paragraphs, and the $FirstIndent indentation is used for the next line.  You can  use  two
       consecutive newlines to have spaced paragraphs emitted from a single reminder body.

       A  RUN-type  reminder  also  passes  the  body  through  the substitution filter, but then
       executes the result as a system command.  A  CAL-type  reminder  is  used  only  to  place
       entries in the calendar produced when Remind is run with the -c, -s or -p options.

       A  PS or PSFILE-type reminder is used to pass PostScript code directly to the printer when
       producing PostScript calendars.  This can be used to shade certain calendar  entries  (see
       the psshade() function), include graphics in the calendar, or almost any other purpose you
       can think of.  You should not use these types  of  reminders  unless  you  are  an  expert
       PostScript  programmer.  The PS and PSFILE reminders are ignored unless Remind is run with
       the -p option.  See the section "More about PostScript" for more details.

       A SPECIAL-type reminder is used  to  pass  "out-of-band"  information  from  Remind  to  a
       calendar-producing  back-end.   It  should  be  followed  by a word indicating the type of
       special data being passed.  The type of a special reminder depends on the  back-end.   For
       the  Rem2PS  back-end, SPECIAL PostScript is equivalent to a PS-type reminder, and SPECIAL
       PSFile is equivalent to a PSFILE-type  reminder.   The  body  of  a  SPECIAL  reminder  is
       obviously  dependent upon the back-end.  A back-end must ignore a SPECIAL that it does not
       recognize.

       DATE SPECIFICATIONS

       A date_spec consists of zero to four parts.  These parts are day  (day  of  month),  month
       (month  name),  year  and  weekday.  Month and weekday are the English names of months and
       weekdays.  At least the first three characters must be used.  The following  are  examples
       of the various parts of a date_spec:

       day:   1, 22, 31, 14, 3

       month: JANUARY, feb, March, ApR, may, Aug

       year:  1990, 1993, 2030.  The year can range from 1990 to 2075.

       weekday:
              Monday, tue, Wed, THU, Friday, saturday, sundAy

       Note that there can be several weekday components separated by spaces in a date_spec.

       INTERPRETATION OF DATE SPECIFICATIONS

       The following examples show how date specifications are interpreted.

       1.  Null date specification - the reminder is triggered every day.  The trigger date for a
       specific run is simply the current system date.  For example:

               REM MSG This is triggered every time Remind runs

       2. Only day present.  The reminder is triggered on the specified day of each  month.   The
       trigger date for a particular run is the closest such day to the current system date.  For
       example:

            REM 1 MSG First of every month.
            REM 31 MSG 31st of every month that has 31 days.

       3. Only month present.  The reminder is  triggered  every  day  of  the  specified  month.
       Example:

            REM Feb MSG Every day in February

       4.  day and month present.  Examples:

            REM 6 Jan MSG Every 6th of January
            REM Feb 29 MSG Every 29th of February

       5.  Only year present. Example:

            REM 1991 MSG Every day in 1991

       6.  year and day present.  Examples:

            REM 1 1990 MSG 1st of every month in 1990
            REM 1992 23 MSG 23rd of every month in 1992

       7.  year and month present.  Examples:

            REM Feb 1991 MSG Every day in Feb 1991
            REM 1992 September MSG Every day in Sept 1992

       8.  year, month and day present.  Examples:

            REM 8 Jan 1991 MSG 8th January 1991.
            REM 1992 March 9 MSG 9th March 1992.

       9.  weekday only.  Examples:

            REM Sat MSG Every Saturday
            REM Mon Tue Wed Thu Fri MSG Every working day
            REM Monday Wednesday MSG Every Monday and Wednesday

       10.  weekday and day present.  Examples:

            REM Sat 1 MSG First Saturday of every month
            REM Mon Tue Wed Thu Fri 15 \
                 MSG 1st working day on or after 15th of every month

       11.  weekday and month present.  Examples:

            REM Mon March MSG Every Monday in March
            REM Mon Tue Wed Thu Fri Feb MSG Every working day in February

       12.  weekday, month and day present.  Examples:

            REM Mon 1 March MSG First Monday in March
            REM Sat Sun 15 July MSG First Sat or Sun on or after 15 July

       13.  weekday and year present.  Example:

            REM Sat Sun 1991 MSG Every Saturday and Sunday in 1991

       14.  weekday, day and year present.  Examples:

            REM Mon 15 1990 MSG 1st Mon after 15th of every month in 1990
            REM Mon Tue Wed Thu Fri 1 1990 \
                 MSG 1st working day of every month in 1990

       15.  weekday, month and year present.  Example:

            REM Mon Wed 1991 Feb MSG Every Mon and Wed in Feb 1991.

       16.  weekday, day, month and year present.  Example:

            REM Mon Tue Wed Thu Fri 28 Oct 1990 \
                 MSG 1st working day on or after 28 October 1990.

       Note  that  when  both  weekday and day are specified, Remind chooses the first date on or
       after the specified day that also satisfies the  weekday  constraint.   It  does  this  by
       picking  the  first  date  on  or  after  the  specified day that is listed in the list of
       weekdays.  Thus, a reminder like:

            REM Mon Tue 28 Oct 1990 MSG Hi

       would be issued only on Monday, 29 October, 1990.  It would not be issued on  Tuesday,  30
       October, 1990, since the 29th is the first date to satisfy the weekday constraints.

       SHORT-HAND DATE SPECIFICATIONS

       In addition to spelling out the day, month and year separately, you can specify YYYY-MM-DD
       or YYYY/MM/DD.  For example, the following statements are equivalent:

            REM 5 June 2010 MSG Cool!
            REM 2010-06-05  MSG Cool!

       You can  also  specify  a  date  and  time  as  YYYY-MM-DD@HH:MM.   These  statements  are
       equivalent:

            REM 19 Dec 2010 AT 16:45 MSG Hi
            REM 2010-12-19@16:45 MSG Hi

       There's  one  subtlety  with short-hand date specifications:  The following statements are
       not equivalent:

            REM 19 Dec 2010 AT 16:45 +60 MSG Hi
            REM 2010-12-19@16:45 +60 MSG Hi

       In the second statement, the "+60" is a delta that applies  to  the  date  rather  than  a
       tdelta  that applies to the time.  We recommend explicitly using the AT keyword with timed
       reminders.

       THE REMIND ALGORITHM

       Remind uses the following algorithm to compute a trigger date: Starting from  the  current
       date,  it  examines each day, one at a time, until it finds a date that satisfies the date
       specification, or proves to itself that no such date  exists.   (Actually,  Remind  merely
       behaves  as if it used this algorithm; it would be much too slow in practice.  Internally,
       Remind uses much faster techniques to  calculate  a  trigger  date.)   See  DETAILS  ABOUT
       TRIGGER COMPUTATION for more information.

       BACKWARD SCANNING

       Sometimes,  it is necessary to specify a date as being a set amount of time before another
       date.  For example, the last Monday in a given month is computed as the  first  Monday  in
       the  next  month,  minus  7  days.  The back specification in the reminder is used in this
       case:

            REM Mon 1 -7 MSG Last Monday of every month.

       A back is specified with one or two dashes followed by an integer.  This causes Remind  to
       move "backwards" from what would normally be the trigger date.  The difference between --7
       and -7 will be explained when the OMIT keyword is described.

       ADVANCE WARNING

       For some reminders, it is appropriate to  receive  advance  warning  of  the  event.   For
       example,  you  may wish to be reminded of someone's birthday several days in advance.  The
       delta portion of the REM command achieves this.  It is specified as one or two  "+"  signs
       followed  by  a  number  n.   Again, the difference between the "+" and "++" forms will be
       explained under the OMIT keyword.  Remind will trigger the reminder  on  computed  trigger
       date, as well as on each of the n days before the event.  Here are some examples:

            REM 6 Jan +5 MSG Remind me of birthday 5 days in advance.

       The  above example would be triggered every 6th of January, as well as the 1st through 5th
       of January.

       PERIODIC REMINDERS

       We have already seen some built-in mechanisms for certain  types  of  periodic  reminders.
       For example, an event occurring every Wednesday could be specified as:

            REM Wed MSG Event!

       However,  events  that  do  not  repeat  daily,  weekly, monthly or yearly require another
       approach.  The repeat component of the REM command fills this need.  To use it,  you  must
       completely specify a date (year, month and day, and optionally weekday); this is the start
       date of the repetition period.  The repeat component is an asterisk followed by  a  number
       specifying the repetition period in days.

       For  example,  suppose  you  get  paid  every  second  Wednesday, and your last payday was
       Wednesday, 28 October, 1992.  You can use:

            REM 28 Oct 1992 *14 MSG Payday

       This issues the reminder every 14 days, starting from 28 Oct 1992.  You can use delta  and
       back with repeat.  Note, however, that the back is used only to compute the starting date;
       thereafter, the reminder repeats with the specified period.  Similarly, if you  specify  a
       weekday,  it  is  used  only  to  calculate  the  starting  date,  and does not affect the
       repetition period.

       SCANFROM and FROM

       The SCANFROM and FROM keywords are for advanced  Remind  programmers  only,  and  will  be
       explained  in the section "DETAILS ABOUT TRIGGER COMPUTATION" near the end of this manual.
       Note that SCANFROM is available only in versions of Remind  from  03.00.04  up.   FROM  is
       available only from 03.01.00 and later.

       PRIORITY

       The  PRIORITY keyword must be followed by a number from 0 to 9999.  It is used in calendar
       mode and when sorting reminders.  If two reminders have the same trigger  date  and  time,
       then  they  are  sorted  by  priority.  If the PRIORITY keyword is not supplied, a default
       priority of 5000 is used.  (This default can be changed by adjusting the  system  variable
       $DefaultPrio.  See the section "SYSTEM VARIABLES" for more information.)

       EXPIRY DATES

       Some  reminders  should  be  issued periodically for a certain time, but then expire.  For
       example, suppose you have a class every Friday, and that your last class is on 11 December
       1992.  You can use:

            REM Fri UNTIL 11 Dec 1992 MSG Class today.

       Another  example:  Suppose you have jury duty from 30 November 1992 until 4 December 1992.
       The following reminder will issue the message every day of your jury duty, as  well  as  2
       days ahead of time:

            REM 1992-11-30 *1 +2 UNTIL 1992-12-04 MSG Jury duty

       Note  that the repeat of *1 is necessary; without it, the reminder would be issued only on
       30 November (and the two days preceding.)

       As a special case, you can use the THROUGH keyword instead of *1 and UNTIL.  The following
       two REM commands are equivalent:

            REM 1992-11-30 *1 +2 UNTIL 1992-12-04 MSG Jury duty

            REM 1992-11-30 +2 THROUGH 1992-12-04 MSG Jury duty

       If you have an expiry date via the use of THROUGH or UNTIL, then Remind will never trigger
       the reminder after the expiry date.  For example, if you have this:

               OMIT 2021-01-08
               REM 2021-01-01 THROUGH 2021-01-08 AFTER MSG Test

       the reminder will not be triggered  on  2021-01-08,  and  nor  will  it  be  triggered  on
       2021-01-09;  even  though  the AFTER keyword would normally move the 8th's reminder to the
       9th, the expiry date of 2021-01-08 overrides that.

       THE ONCE KEYWORD

       Sometimes, it is necessary to ensure that reminders are run only once on a given day.  For
       example, if you have a reminder that makes a backup of your files every Friday:

            REM Fri RUN do_backup

       (Here,  do_backup  is assumed to be a program or shell script that does the work.)  If you
       run Remind from your .login script, for example, and log in several  times  per  day,  the
       do_backup program will be run each time you log in.  If, however, you use the ONCE keyword
       in the reminder, the Remind checks the last access date of the reminder script.  If it  is
       the  same  as  the current date, Remind assumes that it has already been run, and will not
       issue reminders containing the ONCE keyword.

       Note that if you view or edit your reminder script, the last access date will be  updated,
       and  the  ONCE keyword will not operate properly.  If you start Remind with the -o option,
       then the ONCE keyword will be ignored.

       LOCALLY OMITTING WEEKDAYS

       The OMIT portion of the REM command is used to "omit" certain days when counting the delta
       or  back.   It  is  specified  using the keyword OMIT followed by a list of weekdays.  Its
       action is best illustrated with examples:

            REM 1 +1 OMIT Sat Sun MSG Important Event

       This reminder is normally triggered on the first of  every  month,  as  well  as  the  day
       preceding  it.   However,  if the first of the month falls on a Sunday or Monday, then the
       reminder is triggered starting from the previous Friday.  This is because the delta of  +1
       does  not  count  Saturday  or  Sunday  when  it counts backwards from the trigger date to
       determine how much advance warning to give.

       Contrast this with the use of "++1" in the above command.  In this case, the  reminder  is
       triggered  on  the first of each month, as well as the day preceding it.  The omitted days
       are counted.

            REM 1 -1 OMIT Sat Sun MSG Last working day of month

       Again, in the above example, the back of -1 normally causes the trigger  date  to  be  the
       last  day  of  the  month.  However, because of the OMIT clause, if the first of the month
       falls on a Sunday or Monday, the trigger date is  moved  backwards  past  the  weekend  to
       Friday.   (If  you  have  globally  omitted holidays, the reminder will be moved back past
       them, also.  See "The OMIT command" for more details.)

       By comparison, if we had used "--1", the reminder would be triggered on the  last  day  of
       the month, regardless of the OMIT.

       If  you  locally  omit  weekdays but also have globally-omitted weekdays, then the list of
       omitted weekdays is the union of the two.  Consider this example:

               OMIT Sat Sun
               REM 15 OMIT Fri Sat MSG Whatever

       In the REM command, the effective list of omitted weekdays will be  Friday,  Saturday  and
       Sunday.

       COMPUTED LOCAL OMITS

       The  OMITFUNC  phrase  of  the REM command allows you to supply a function that determines
       whether or not a date is omitted.  The function is passed a single parameter of type DATE,
       and  must  return  a non-zero integer if the date is considered "omitted" and 0 otherwise.
       Here's an example:

               FSET _third(x) (day(x) % 3) || \
                              (wkdaynum(x) == 0) || \
                              (wkdaynum(x) == 6)
               REM OMITFUNC _third AFTER MSG Working day divisible by 3

       In the example above, the reminder is triggered every Monday to Friday whose  day-of-month
       number is divisible by three.  Here's how it works:

       o      The OMITFUNC _third portion causes all days for which _third(x) returns non-zero to
              be considered "omitted".  This causes all days whose day-of-month number is  not  a
              multiple  of  three  to  be omitted.  Note that _third also returns non-zero if the
              weekday is Sunday or Saturday.

       o      The AFTER keyword causes the reminder to be moved after a block of omitted days.

       The combination of OMITFUNC and AFTER keyword causes the reminder to be issued on all days
       whose day-of-month number is divisible by three, but not on Saturday or Sunday.

       Note  that  if you use OMITFUNC, then a local OMIT is ignored as are all global OMITs.  If
       you want to omit specific weekdays,  your  omit  function  will  need  to  test  for  them
       specifically.   If  you  want to take into account the global OMIT context, then your omit
       function will need to test for that explicitly (using the isomitted() function.)

       Note that an incorrect OMITFUNC might cause all days to be considered omitted.   For  that
       reason,  when  Remind  searches  through  omitted days, it terminates the search after the
       SATISFY iteration limit (command-line option -x.)

       ADDING TRIGGER DATES TO THE OMIT CONTEXT

       If the ADDOMIT keyword appears in a REM command, then the trigger date (if  one  could  be
       calculated) is automatically added to the list of global OMITs.

       The command:

               REM ... whatever ... ADDOMIT MSG Foo

       is identical in behaviour to the sequence:

               REM ... whatever ... SATISFY 1
               IF trigvalid()
                   OMIT [trigdate()] MSG Foo
               ENDIF

       TIMED REMINDERS

       Timed  reminders  are those that have an AT keyword followed by a time and optional tdelta
       and trepeat.  The time  may  be  specified  in  24-hour  format,  with  0:00  representing
       midnight,  12:00  representing  noon,  and  23:59  representing  one  minute  to midnight.
       Alternatively, it may be specified in common "AM/PM" format; in this case, the  hour  must
       range  from  1  to  12.  12:00am represents midnight, 12:00pm represents noon, and 11:59pm
       represents one minute to midnight.  The "am" and "pm" portions  are  case-insensitive  and
       the "m" is optional.

       You  can  use either a colon or a period to separate the hours from the minutes.  That is,
       13:39 and 13.39 are equivalent.

       Remind treats timed reminders specially.  If the trigger date for a timed reminder is  the
       same as the current system date, the reminder is queued for later activation.  When Remind
       has finished processing the reminder file, it puts itself in the background, and activates
       timed reminders when the system time reached the specified time.  Note that if you use the
       NOQUEUE modifier in the REM command, then this queuing and background  activation  is  not
       performed.   NOQUEUE is useful if you want a time to be associated with a reminder (eg, in
       the calendar) but are not interested in a popup reminder happening at the specified time.

       If the trigger date is not the same as the system date, the reminder is not queued.

       For example, the following reminder, triggered every working  day,  will  emit  a  message
       telling you to leave at 5:00pm:

            REM Mon Tue Wed Thu Fri AT 17:00 MSG Time to leave!

       The following reminder will be triggered on Thursdays and Fridays, but will only be queued
       on Fridays:

            REM Fri ++1 AT 1:00PM MSG Lunch at 1pm Friday.

       The tdelta and trepeat have the same form as a repeat and  delta,  but  are  specified  in
       minutes.   For  example,  this reminder will be triggered at 12:00pm as well as 45 minutes
       before:

            REM AT 12:00 +45 MSG Example

       The following will be issued starting at 10:45, every half hour until 11:45, and again  at
       noon.

            REM AT 12:00 +75 *30 MSG Example2

       The  "+75"  means  that  the  reminder is issued starting 75 minutes before noon; in other
       words, at 10:45.  The *30 specifies that the reminder is subsequently to be  issued  every
       30  minutes.   Note  that the reminder is always issued at the specified time, even if the
       tdelta is not a multiple of the trepeat.  So the  above  example  is  issued  at  10:45am,
       11:15am,  11:45am,  and  12:00pm.   Note  that  in  the  time  specification,  there is no
       distinction between the "+" and "++" forms of tdelta.

       Normally, Remind will issue timed reminders as it processes the reminder script,  as  well
       as  queuing  them  for  later.   If  you  do  not  want Remind to issue the reminders when
       processing the script, but only to queue them for later, use the -a  command-line  option.
       If you do not want reminders to be queued for later, use the -q command-line option.

       Normally,  Remind  forks  a  background  process  to handle queued reminders.  If you want
       Remind to remain in the foreground, use the -f command-line option.  This is  useful,  for
       example, in .xinitrc scripts, where you can use the command:

            remind -fa myreminders &

       This ensures that when you exit X-Windows, the Remind process is killed.

       WARNING ABOUT TIMED REMINDERS

       Note:   If  you use user-defined functions or variables (described later) in the bodies of
       timed reminders, then when the timed reminders are activated, the variables and  functions
       have  the  definitions  that  were  in  effect  at  the end of the reminder script.  These
       definitions may not necessarily be those that were in effect at the time the reminder  was
       queued.   In  addition,  the  OMIT  context  is  whatever  was in effect at the end of the
       reminder script, which may not necessarily be the same as when the REM command  was  first
       processed.

       THE SCHED AND WARN KEYWORDS

       The  SCHED keyword allows more precise control over the triggering of timed reminders, and
       the WARN keyword allows precise control over  the  advance  triggering  of  all  types  of
       reminders.   However, discussion must be deferred until after expressions and user-defined
       functions are explained.  See the subsection "PRECISE SCHEDULING" further on.

       TAG AND DURATION

       The TAG keyword lets you "tag" certain reminders.  This facility is used by certain  back-
       ends  or  systems  built  around  Remind, such as TkRemind.  These back-ends have specific
       rules about tags; see their documentation for details.

       The TAG keyword is followed by a tag consisting of up to 48 characters.  You can  have  as
       many  TAG  clauses  as you like in a given REM statement.  A tag can contain any character
       except for whitespace and a comma.

       If you supply the -y option to Remind, then any reminder that lacks a TAG  will  have  one
       synthesized.   The  synthesized  tag  consists of the characters "__syn__" followed by the
       hexadecimal representation of the MD5 sum of the REM command line.  This lets you  give  a
       more-or-less unique identifier to each distinct REM command.

       The DURATION keyword makes sense only for timed reminders; it specifies the duration of an
       event.  For example, if you have a 90-minute meeting starting at 1:00pm, you could use any
       of the following:

            REM 5 March 2021 AT 13:00 DURATION 1:30 MSG Meeting
            REM 5 March 2021 AT 13:00 DURATION 90 MSG Meeting
            REM 5 March 2021 AT 1:00pm DURATION 1:30 MSG Meeting
            REM 5 March 2021 AT 1:00pm DURATION 90 MSG Meeting

       For  long-duration  reminders, it is convenient to use expressions to simplify writing the
       DURATION.  For example, if you are away from 20 Feb 2023 through 23 Feb 2023 (a total of 4
       days) you could write:

               REM 20 Feb AT 00:00 DURATION [4*24]:00 MSG away
               REM 20 Feb AT 00:00 DURATION [4*24*60] MSG away

       Note that duration is specified either as hours:minutes or just as minutes specified as an
       integer.

       If you specify a duration of 00:00 or 0, then Remind behaves exactly as if no DURATION  at
       all  had  been  present.  Although durations specified as hours:minutes look superficially
       like a time-of-day, they are not; the hours component is not limited to the range 00-23.

SYNTACTIC SUGAR FOR REM

       The REM command has syntactic sugar to let you express common  reminders.   The  following
       pairs of reminders are equivalent:

           REM First Monday April MSG Foo
           REM Mon 1 April        MSG Foo

           REM Second Monday May  MSG Bar
           REM Mon 8 May          MSG Bar

           REM Third Monday MSG Third Monday of every month
           REM Mon 15 MSG Third Monday of every month

           REM Fourth Sunday June 2025 MSG Fourth Sunday in June 2025
           REM Sun 22 June 2025 MSG Fourth Sunday in June 2025

           REM Last Monday MSG Last Monday of every month
           REM Mon 1 --7 MSG Last Monday of every month

           REM Last Monday April MSG Last Monday of every April
           REM Mon 1 May --7 MSG  Last Monday of every April

           REM Last Monday December 2025 MSG Last Monday of Dec 2025
           REM Monday 1 Jan 2026 --7 MSG Last Monday of Dec 2025

       Note  that Last effectively adjusts the month and year, if necessary, to make the reminder
       trigger on the correct date.

       The keyword IN is completely ignored, so you can write (for example):

           REM Second Monday in May MSG foo
           REM Last Monday in December 2025 MSG Bar

       An alternate form of back  makes  writing  reminders  easier.   The  following  groups  of
       reminders are equivalent:

           REM ~~1 MSG Last day of every month
           REM Lastday MSG  Last day of every month
           REM 1 --1 MSG Last day of every month

           REM May ~~1 MSG Last day of May
           REM Lastday May MSG Last day of May
           REM 1 June --1 MSG Last day of May

           REM Dec 2025 ~~1 MSG Last day of December 2025
           REM Lastday Dec 2025 MSG Last day of December 2025
           REM 1 Jan 2026 --1 MSG Last day of December 2025

           REM Apr ~1 OMIT SAT SUN MSG Last workday of April
           REM Lastworkday April OMIT SAT SUN MSG Last workday of April
           REM 1 May -1 OMIT SAT SUN MSG Last workday of April

           REM Apr ~~7 MSG Seventh-last day of April
           REM 1 May --7 MSG Seventh-last day of April

           REM Apr ~2 OMIT SAT SUN MSG Second-last workday of April
           REM 1 May -2 OMIT SAT SUN MSG Second-last workday of April

       As we see, "Lastday" is equivalent to ~~1 and "Lastworkday" to ~1.

       Note  that the First/Second/Third/Fourth/Last keywords and the ~ and ~~ form of back imply
       a value for the day  of  the  month;  as  such,  they  cannot  be  combined  with  a  day.
       Additionally,  First/Second/Third/Fourth/Last  must  have  at least one weekday name.  The
       following are illegal:

           REM First Monday 3 June MSG Huh?
           REM April 3 ~~1 MSG What?
           REM Second June MSG Where's the weekday???

THE SUBSTITUTION FILTER

       Before being processed, the body of a REM command is passed through a substitution filter.
       The filter scans for sequences "%x" (where "x" is any letter and certain other characters)
       and performs substitutions as shown below.  (All dates refer to the trigger  date  of  the
       reminder.)

       %a     is replaced with "on weekday, day month, year"
              For example, consider the reminder:

              REM 18 Oct 1990 +4 MSG Meeting with Bob %a.

              On  16  October  1990,  it  would  print "Meeting with Bob on Thursday, 18 October,
              1990."

              On 17 October 1990, it would print "Meeting with Bob tomorrow."

              On 18 October 1990, it would print "Meeting with Bob today."

       %b     is replaced with "in diff day's time" where diff  is  the  actual  number  of  days
              between the current date and the trigger date.  (OMITs have no effect.)
              For example, consider:

              REM 18 Oct 1990 +4 MSG Meeting with Bob %b.

              On 16 October 1990, it would print "Meeting with Bob in 2 days' time."

              On 17 October 1990, it would print "Meeting with Bob tomorrow."

              On 18 October 1990, it would print "Meeting with Bob today."

       %c     is replaced with "on weekday"
              Example: REM 18 Oct 1990 +4 MSG Meeting with Bob %c.

              On 16 October 1990, it would print "Meeting with Bob on Thursday."

              On 17 October 1990, it would print "Meeting with Bob tomorrow."

              On 18 October 1990, it would print "Meeting with Bob today."

       %d     is replaced with "day", the day of the month.

       %e     is replaced with "on dd-mm-yyyy"

       %f     is replaced with "on mm-dd-yyyy"

       %g     is replaced with "on weekday, day month"

       %h     is replaced with "on dd-mm"

       %i     is replaced with "on mm-dd"

       %j     is replaced with "on weekday, month day-th, year"  This form appends the characters
              "st", "nd", "rd" or "th" to the day of the month, as appropriate.

       %k     is replaced with "on weekday, month day-th"

       %l     is replaced with "on yyyy-mm-dd"

       %m     is replaced with "month", the name of the month.

       %n     is replaced with the number (1 to 12) of the month.

       %o     is replaced with " (today)" if and only if the current system date is the  same  as
              the  date  being used by Remind as the current date.  Recall that you can specify a
              date for Remind to use on the command line.  This  substitution  is  not  generally
              useful  in  a  REM  command,  but  is useful in a BANNER command.  (See "The BANNER
              Command.")

       %p     is replaced with "s" if the diff between the current date and the trigger  date  is
              not 1.  You can use this to construct reminders like:
              REM 1 Jan +4 MSG %x day%p to go before New Year!

       %q     is  replaced with "'s" if the diff between the trigger date and the current date is
              1.  Otherwise, it is replaced with "s'"  This can be used as follows:
              REM 1 Jan +4 MSG New Year in %x day%q time!

       %r     is replaced with the day of the month (01 to 31) padded  with  a  leading  zero  if
              needed to pad to two digits.

       %s     is replaced with "st", "nd", "rd" or "th" depending on the day of the month.

       %t     is  replaced  with  the  number of the month (01 to 12) padded to two digits with a
              leading zero.

       %u     is replaced with "on weekday, day-th month, year"  This is  similar  to  %a  except
              that "st", "nd", "rd" or "th" is added to the day as appropriate.

       %v     is replaced with "on weekday, day-th month"

       %w     is replaced with "weekday", the name of the day of the week.

       %x     is  replaced with the diff between the current date and the trigger date.  The diff
              is defined as the actual number of days between these  two  dates;  OMITs  are  not
              counted.  (Strict date subtraction is performed.)

       %y     is replaced with "year", the year of the trigger date.

       %z     is replaced with "yy", the last two digits of the year.

       %_     (percent-underscore)  is  replaced  with  a  newline.   You can use this to achieve
              multi-line reminders.

       %1     is replaced with "now", "m minutes from now", "m minutes ago", "h hours from  now",
              "h  hours ago", "h hours and m minutes from now" or "h hours and m minutes ago", as
              appropriate for a timed reminder.  Note that unless  you  specify  the  -a  option,
              timed  reminders will be triggered like normal reminders, and thus a timed reminder
              that occurred earlier in the day may be triggered.  This causes the  need  for  the
              "...ago" forms.

       %2     is replaced with "at hh:mmam" or "..pm" depending on the AT time of the reminder.

       %3     is replaced with "at hh:mm" in 24-hour format.

       %4     is  replaced with "mm" where mm is the number of minutes between "now" and the time
              specified by AT.  If the AT time is earlier than the current time, then the  result
              is negative.

       %5     is replaced with "ma" where ma is the absolute value of the number produced by %4.

       %6     is  replaced with "ago" or "from now", depending on the relationship between the AT
              time and the current time.

       %7     is replaced with the number of hours between the AT time and the current time.   It
              is always non-negative.

       %8     is  replaced  with  the number of minutes between the AT time and the current time,
              after the hours (%7) have been subtracted out.  This is a number ranging from 0  to
              59.

       %9     is replaced with "s" if the value produced by %8 is not 1.

       %0     is replaced with "s" if the value produced by %7 is not 1.

       %!     is  replaced with "is" if the current time is before the AT time, or "was" if it is
              after.

       %@     is similar to %2 but displays the current time.

       %#     is similar to %3 but displays the current time.

       %"     (percent-doublequote  -  ")  is  removed.   This  sequence  is  not  used  by   the
              substitution filter, but is used to tell Remind which text to include in a calendar
              entry when the -c, -s or -p option is chosen.  See "CALENDAR MODE"

       Notes:

       o      Remind normally prints a blank line after each reminder; if the last  character  of
              the body is "%", the blank line will not be printed.  You can globally suppress the
              extra blank lines by setting $AddBlankLines to 0.

       o      Substitutions a, b, c, e, f, g, h, i, j, k, l,  u  and  v  all  are  replaced  with
              "today"  if  the current date equals the trigger date, or "tomorrow" if the trigger
              date is one  day  after  the  current  date.   Thus,  they  are  not  the  same  as
              substitutions built up from the simpler %w, %y, etc.  sequences.

       o      The  a,  c, e, f, g, h, i, j, k, l, u, v, 2, and 3 substitutions may be preceded by
              an asterisk (for example, %*c) which causes  the  word  "at"  or  "on"  that  would
              normally be included in the output to be omitted.

       o      Any of the substitutions dealing with time (0 through 9 and '!')  produce undefined
              results if used in a reminder that does  not  have  an  AT  keyword.   Also,  if  a
              reminder  has  a delta and may be triggered on several days, the time substitutions
              ignore the date.  Thus, the %1 substitution may report that  a  meeting  is  in  15
              minutes,  for  example,  even though it may only be in 2 days time, because a delta
              has triggered the reminder.  It is recommended that you use the time  substitutions
              only  in  timed  reminders  with  no delta that are designed to be queued for timed
              activation.

       o      Capital letters can be used in the substitution sequence, in which case  the  first
              character  of the substituted string is capitalized (if it is normally a lower-case
              letter.)

       o      All other characters following a "%" sign are simply copied.  In particular, to get
              a  "%"  sign  out,  use  "%%"  in the body.  To start the body of a reminder with a
              space, use "% ", since Remind normally scans  for  the  first  non-space  character
              after a MSG, CAL or RUN token.

THE OMIT COMMAND

       In  addition  to  being  a keyword in the REM command, OMIT is a command in its own right.
       Its syntax is:

              OMIT weekday [weekday...]

              or:

              OMIT [day] month [year]

              or:

              OMIT [day1] month1 [year1] THROUGH [day2] month2 [year2]

       The OMIT command is used to  "globally"  omit  certain  days  (usually  holidays).   These
       globally-omitted  days  are skipped by the "-" and "+" forms of back and delta, but not by
       the "--" and "++" forms.  Some examples:

           OMIT Saturday Sunday
           OMIT 1 Jan
           OMIT 7 Sep 1992
           OMIT 15 Jan THROUGH 14 Feb
           OMIT May     # Equivalent to OMIT May 1 THROUGH May 31
           OMIT 25 Dec THROUGH 4 Jan
           OMIT 2023-05-03 THROUGH 2023-05-12
           OMIT Jun THROUGH July  # Equivalent to OMIT Jun 1 THROUGH July 31

       The first example omits every Saturday and Sunday.  This  is  useful  for  reminders  that
       shouldn't trigger on weekends.

       The second example specifies a holiday that occurs on the same date each year - New Year's
       Day.

       The third example specifies a holiday that changes each year  -  Labour  Day.   For  these
       types  of  holidays,  you  must  create  an  OMIT  command  for each year.  (Later, in the
       description of expressions and some of the more advanced features of Remind, you will  see
       how to automate this for some cases.)

       As  with  the  REM  command, you can use shorthand specifiers for dates; the following are
       equivalent:

            OMIT 7 Sep 1992
            OMIT 1992-09-07

       For convenience, you can use a delta and MSG or RUN keyword  in  the  OMIT  command.   The
       following sequences are equivalent:

            OMIT 1 Jan
            REM 1 Jan +4 MSG New year's day is %b!

            and

            OMIT 1 Jan +4 MSG New year's day is %b!

       The  THROUGH  keyword  lets  you  conveniently  OMIT  a  range  of days.  For example, the
       following sequences are equivalent:

            OMIT 3 Jan 2011
            OMIT 4 Jan 2011
            OMIT 5 Jan 2011

            and

            OMIT 3 Jan 2011 THROUGH 5 Jan 2011

       Note that Remind has a compiled-in limit to the number of full OMITs.  If you omit a range
       of  N  fully-specified (ie, year included) days, then N full OMITs are used up.  Trying to
       omit a very large range may result in the error "Too many full OMITs"

       You can make a THROUGH OMIT do double-duty as a REM command as  long  as  both  dates  are
       fully specified

            OMIT 6 Sep 2010 THROUGH 10 Sep 2010 MSG Vacation

       If  you  use  a THROUGH clause, then either the year must be supplied before and after the
       THROUGH, or it must be missing before and after the THROUGH.  The following are legal:

           OMIT 25 Dec THROUGH 6 Jan
           OMIT 25 Dec 2024 THROUGH 6 Jan 2025

       But the following are not:

           OMIT 25 Dec THROUGH 6 Jan 2025
           OMIT 25 Dec 2024 THROUGH 6 Jan

       You can debug your global OMITs with the following command:

            OMIT DUMP

       The OMIT DUMP command prints the current global omits to standard output.

       THE BEFORE, AFTER AND SKIP KEYWORDS

       Normally, days that are omitted, whether by a global OMIT command or  the  local  OMIT  or
       OMITFUNC keywords in a REM statement, only affect the counting of the -back or the +delta.
       For example, suppose you have a meeting every Wednesday.   Suppose,  too,  that  you  have
       indicated 11 Nov as a holiday:

            OMIT 11 Nov +4 MSG Remembrance Day
            REM Wed +1 MSG Code meeting %b.

       The  above sequence will issue a reminder about a meeting for 11 November 1992, which is a
       Wednesday.  This is probably incorrect.  There are three options:

       BEFORE This keyword moves the reminder to before any omitted days.   Thus,  in  the  above
              example, use of BEFORE would cause the meeting reminder to be triggered on Tuesday,
              10 November 1992.

       AFTER  This keyword moves the reminder to after any omitted days.  In the  above  example,
              the meeting reminder would be triggered on Thursday, 12 November 1992.

       SKIP   This  keyword  causes  the  reminder  to be skipped completely on any omitted days.
              Thus, in the above example, the reminder would not  be  triggered  on  11  November
              1992.   However,  it  would  be  triggered  as usual on the following Wednesday, 18
              November 1992.

       The BEFORE and AFTER keywords move the trigger date of a reminder to  before  or  after  a
       block  of  omitted days, respectively.  Suppose you normally run a backup on the first day
       of the month.  However, if the first day of the month is a weekend or holiday, you run the
       backup on the first working day following the weekend or holiday.  You could use:

            REM 1 OMIT Sat Sun AFTER RUN do_backup

       Let's  examine  how  the  trigger  date is computed.  The 1 specifies the first day of the
       month.  The local OMIT keyword causes the AFTER keyword to move the reminder forward  past
       weekends.   Finally,  the AFTER keyword will keep moving the reminder forward until it has
       passed any holidays specified with global OMIT commands.

THE DO AND INCLUDE COMMANDS

       Remind allows you to include other files  in  your  reminder  script,  similar  to  the  C
       preprocessor  #include  directive.   For example, your system administrator may maintain a
       file of holidays or system-wide reminders.  You can include these in your reminder  script
       as follows:

            INCLUDE /usr/share/remind/holidays
            INCLUDE /usr/share/remind/reminders

       (The actual pathnames vary from system to system - ask your system administrator.)

       INCLUDE files can be nested up to a depth of 8.

       If  you  specify  a filename of "-" in the INCLUDE command, Remind will begin reading from
       standard input.

       If you specify a directory as the argument to INCLUDE, then Remind will process all  files
       in that directory that match the shell pattern "*.rem".  The files are processed in sorted
       order; the sort order matches that used by the shell when it expands "*.rem".

       Note that the file specified by an INCLUDE command is interpreted relative to the  current
       working  directory  of  the Remind process.  If you want to include a file relative to the
       directory containing the currently-processing file, use DO instead.  For example,  if  the
       current   file   is   /home/user/.reminders/foo.rem  and  Remind's  working  directory  is
       /home/user, then:

           # Read /home/user/.reminders/bar.rem
           DO bar.rem

           # Read /usr/share/bar.rem - absolute path
           DO /usr/share/bar.rem

           # Read /home/user/bar.rem
           INCLUDE bar.rem

           # Read /usr/share/bar.rem - absolute path
           INCLUDE /usr/share/bar.rem

       Arguably, the INCLUDE command should have worked the way DO does right from the start, but
       changing it would have broken backward-compatibility, hence the introduction of DO.

       Note that if the currently-processing reminders file was specified as a symbolic link to a
       file that is not in the same directory as the symbolic link itself, DO will fail.   Remind
       does not resolve the real path of symbolic links, so you should avoid using symbolic links
       to files.

THE RUN COMMAND

       If you include other files in your reminder script, you may not always entirely trust  the
       contents  of the other files.  For example, they may contain RUN-type reminders that could
       be used to access your files or perform undesired actions.  The RUN command  can  restrict
       this:   If you include the command RUN OFF in your top-level reminder script, any reminder
       or expression that would normally execute a system command is disabled.  RUN ON  will  re-
       enable the execution of system commands.  Note that the RUN ON command can only be used in
       your top-level reminder script; it will not work in any  files  accessed  by  the  INCLUDE
       command.   This  is  to  protect  you from someone placing a RUN ON command in an included
       file.  However, the RUN OFF command can be used at top level or in an included file.

       If you run Remind with the -r command-line option,  RUN-type  reminders  and  the  shell()
       function  will  be  disabled,  regardless  of  any  RUN  commands  in the reminder script.
       However, any command supplied with the -k option will still be executed.

       One use of the RUN command is to provide a secure interface between  Remind  and  the  Elm
       mail system.  The Elm system can automatically scan incoming mail for reminder or calendar
       entries, and place them in your calendar file.  To use this feature, you  should  set  the
       calendar  filename  option under Elm to be something like "~/.reminders.in", not your main
       reminder file!  This is so that any RUN ON commands mailed to you can never be activated.

       Then, you can use the Elm scan message for calendar entries  command  to  place  reminders
       prefaced  by "->" into .reminders.in.  In your main .reminders file, include the following
       lines:

            RUN OFF   # Disable RUN
            INCLUDE .reminders.in
            RUN ON    # Re-enable RUN

       In addition, Remind contains a few other security features.  It will not read a file  that
       is  group- or world-writable.  It will not run set-uid.  If it reads a file you don't own,
       it will disable RUN and the shell() function.  And if it is run as root, it will only read
       files owned by root.

       Note  that  if  Remind reads standard input, it does not attempt to check the ownership of
       standard input, even if it is coming from a file, and  hence  does  not  disable  RUN  and
       shell() in this situation.

THE INCLUDECMD COMMAND

       Remind allows you to execute a shell command and evaluate the output of that command as if
       it were an included file.  For example, you could have scripts that extract reminders  out
       of a database and print them on stdout as REM commands.  Here is an example:

            INCLUDECMD extract_reminders_for dfs

       We  assume  that  the  command "extract_reminders_for" extracts reminders out of a central
       database for the named user.  Another use-case of INCLUDECMD is if you have your reminders
       stored  in  a file in some non-Remind format; you can write a command that transforms them
       to Remind format and then Remind can "include" the file  with  an  appropriate  INCLUDECMD
       command.

       Note  that  if  RUN  is  disabled,  then  INCLUDECMD will fail with the error message "RUN
       disabled"

       INCLUDECMD passes the rest of the line to popen(3), meaning that the command  is  executed
       by  the  shell.   As  such,  shell  metacharacters may need escaping or arguments quoting,
       depending on what you're trying to do.  Remind itself does not perform any modification of
       the command line (apart from the normal [expr] expression-pasting mechanism).

       If  the  command  passed  to  INCLUDECMD  begins with an exclamation mark "!", then Remind
       disables RUN for the output of the command.  If you are running a command whose output you
       don't quite trust, you should prefix it with "!" so that any RUN commands it emits fail.

       An INCLUDECMD command counts towards the INCLUDE nesting depth.  For any given Remind run,
       a given INCLUDECMD command is only executed once and the results are cached.  For example,
       if  you generate a calendar, each unique INCLUDECMD command is run just once, not once for
       each day of the produced calendar.  "Uniqueness" is determined by looking at  the  command
       that  will  be  passed  to the shell, so if (for example) your INCLUDECMD uses expression-
       pasting that results in differences depending on the value of today(),  then  each  unique
       version of the command will be executed once.

THE BANNER COMMAND

       When Remind first issues a reminder, it prints a message like this:

            Reminders for Friday, 30th October, 1992 (today):

       (The  banner is not printed if any of the calendar-producing options is used, or if the -k
       option is used.)

       The BANNER command lets you change the format.  It should appear before any REM  commands.
       The format is:

              BANNER format

       The format is similar to the body of a REM command.  It is passed through the substitution
       filter, with an implicit trigger of the current system date.  Thus, the default banner  is
       equivalent to:

            BANNER Reminders for %w, %d%s %m, %y%o:

       You can disable the banner completely with BANNER %.  Or you can create a custom banner:

            BANNER Hi - here are your reminders for %y-%t-%r:

CONTROLLING THE OMIT CONTEXT

       Sometimes,  it is necessary to temporarily change the global OMITs that are in force for a
       few reminders.  Three commands allow you to do this:

       PUSH-OMIT-CONTEXT
              This command saves the current global OMITs on an internal stack.

       CLEAR-OMIT-CONTEXT
              This command clears all of the global OMITs, starting you off with a "clean slate."

       POP-OMIT-CONTEXT
              This command restores the global OMITs that were saved by  the  most  recent  PUSH-
              OMIT-CONTEXT.

       For  example, suppose you have a block of reminders that require a clear OMIT context, and
       that they also introduce unwanted global OMITs that could interfere with later  reminders.
       You could use the following fragment:

            PUSH-OMIT-CONTEXT   # Save the current context
            CLEAR-OMIT-CONTEXT  # Clean the slate
            # Block of reminders goes here
            POP-OMIT-CONTEXT    # Restore the saved omit context

EXPRESSIONS

       In certain contexts, to be described later, Remind will accept expressions for evaluation.
       Remind expressions resemble C expressions, but operate on different types of objects.

       DATA TYPES

       Remind expressions operate on five types of objects:

       INT    The INT data type consists of the integers representable in one machine word.   The
              INT data type corresponds to the C "int" type.

       STRING The  STRING data type consists of strings of characters.  It is somewhat comparable
              to a C character array, but more closely resembles the string type in BASIC.

       TIME   The TIME data type is used for two different purposes:  To represent a time of  day
              with  one-minute  precision  or  to represent a duration with one-minute precision.
              The context of where a TIME is used determines whether it is interpreted as a  time
              of day or a duration.

              In contexts where a TIME represents a time of day, it may range from 00:00 to 23:59
              and is stored internally as an integer from 0 to 1439 representing  the  number  of
              minutes since midnight.

              In contexts where a TIME represents a duration, there is no upper limit on the hour
              component (beyond that imposed by the restriction  that  a  duration  expressed  in
              minutes  must  fit  into  the  signed  integer  type  of  your  CPU  architecture.)
              Internally, a duration is stored as an integer number of minutes.

       DATE   The DATE data type consists of dates (later than 1 January 1990.)  Internally, DATE
              objects are stored as the number of days since 1 January 1990.

       DATETIME
              The  DATETIME data type consists of a date and time together.  Internally, DATETIME
              objects are stored as the number of minutes since midnight, 1  January  1990.   You
              can think of a DATETIME object as being the combination of DATE and TIME parts.

       CONSTANTS

       The following examples illustrate constants in Remind expressions:

       INT constants
              12, 36, -10, 0, 1209

       STRING constants
              "Hello there", "This is a test", "\nHello\tThere", ""

              Note  that  the  empty  string  is  represented  by "".  Remind supports the escape
              sequences "\a", "\b", "\f", "\n", "\r", "\t" and "\v" which have the same  meanings
              as  their  counterparts in C.  To include a quote in a string, use "\"".  Any other
              character preceded by a backslash is  inserted  into  the  string  as-is,  but  the
              backslash itself is removed.  To include a backslash in a string, use "\\".

       TIME constants
              12:33, 0:01, 14:15, 16:42, 12.16, 13.00, 1.11, 4:30PM, 12:20am

              Note  that  TIME  constants  may  be written in 24-hour format or in common "AM/PM"
              format.  If you use "AM/PM" format, then the hour can range from 1 to 12.  Either a
              period  or  colon  can  be  used  to separate the minutes from the hours.  However,
              Remind will consistently output times in 24-hour format using  only  one  separator
              character.  (The output separator character is chosen at compile-time.)

              If  the  TIME  is  used  where  Remind expects a time-of-day (for example, in an AT
              clause), then it can be written in 24-hour format (ranging from 00:00 to 23:59)  or
              12-hour format (ranging from 12:00am to 11:59pm).  If the TIME is used where Remind
              expects a duration, it must not have an am or pm suffix and  the  hour  can  be  as
              large as you want, so long as the total number of minutes in the duration fits in a
              signed integer variable.

       DATE constants
              DATE constants are expressed as 'yyyy/mm/dd' or 'yyyy-mm-dd', and the single quotes
              must  be  supplied.  This distinguishes date constants from division or subtraction
              of integers.  Examples:

              '1993/02/22', '1992-12-25', '1999/01/01'

              Note that DATE values are printed without the quotes.  Although either '-'  or  '/'
              is  accepted as a date separator on input, when dates are printed, only one will be
              used.  The choice of whether to use '-' or '/' is made at compile-time.  Note  also
              that versions of Remind prior to 03.00.01 did not support date constants.  In those
              versions, you must create dates using the date() function.  Also, versions prior to
              03.00.02 did not support the '-' date separator.

       DATETIME constants
              DATETIME  constants  are expressed similarly to DATE constants with the addition of
              an "@HH:MM" part, optionally followed by "am" or "pm".  For example:

              '2008-04-05@23:11', '1999/02/03@14:06', '2001-04-07@08:30', '2020-01-01@3:20pm'

              DATETIME values are  printed  without  the  quotes.   Notes  about  date  and  time
              separator characters for DATE and TIME constants apply also to DATETIME constants.

       ZERO VALUES

       The non-string types all have an associated zero value, which is treated as "false" by the
       IF command and the logical operators.  The zero values are:

              INT - 0

              DATE - '1990-01-01'

              TIME - 00:00

              DATETIME - '1990-01-01@00:00'

       Additionally, for the purpose of the IF command (but not the logical operators) the  empty
       string "" is considered a false value.

       OPERATORS

       Remind  has  the  following  operators.  Operators on the same line have equal precedence,
       while operators on lower lines have lower precedence than  those  on  higher  lines.   The
       operators approximately correspond to C operators.

            !  -     (unary logical negation and arithmetic negation)
            *  /  %
            +  -
            <  <=  >  >=
            ==  !=
            &&
            ||

       DESCRIPTION OF OPERATORS

       !      Logical  negation.   Can  be  applied  to an INT type.  If the operand is non-zero,
              returns zero.  Otherwise, returns 1.

       -      Unary minus.  Can be applied to an INT.  Returns the negative of the operand.

       *      Multiplication.  Returns the product of two INTs.  Alternatively, if  one  argument
              is  a STRING and the other an INT, returns a STRING consisting of the INT number of
              repeats of the original STRING.  In this case, the INT argument cannot be negative.

       /      Integer division.  Returns the quotient of two INTs, discarding the remainder.

       %      Modulus.  Returns the remainder upon dividing one INT by another.

       +      Has several uses.  These are:

              INT + INT - returns the sum of two INTs.

              INT + TIME or TIME + INT - returns a TIME obtained by adding  INT  minutes  to  the
              original TIME.  The result will always range from 00:00 through 23:59.

              TIME  +  TIME  treats  the second TIME parameter as a duration, converting it to an
              integer number of minutes past midnight, and then performs addition as with TIME  +
              INT.

              INT  +  DATE  or  DATE  +  INT  - returns a DATE obtained by adding INT days to the
              original DATE.

              INT + DATETIME or DATETIME + INT -  returns  a  DATETIME  obtained  by  adding  INT
              minutes to the original DATETIME.

              DATETIME  +  TIME  or  TIME  +  DATETIME  treats  the TIME parameter as a duration,
              converting it to an integer number of minutes  past  midnight,  and  then  performs
              addition as with DATETIME + INT.

              STRING  +  STRING  - returns a STRING that is the concatenation of the two original
              STRINGs.

              STRING + anything or anything + STRING - converts  the  non-STRING  argument  to  a
              STRING, and then performs concatenation.  See the coerce() function.

       -      Has several uses.  These are:

              INT - INT - returns the difference of two INTs.

              DATE - DATE - returns (as an INT) the difference in days between two DATEs.

              TIME - TIME - returns (as an INT) the difference in minutes between two TIMEs.

              DATETIME  -  DATETIME  -  returns (as an INT) the difference in minutes between two
              DATETIMEs.

              DATE - INT - returns a DATE that is INT days earlier than the original DATE.

              TIME - INT - returns a TIME that is INT minutes earlier than the original TIME.

              DATETIME - INT - returns a DATETIME that is INT minutes earlier than  the  original
              DATETIME.

              DATETIME  -  TIME  -  coerces  the  TIME to an INT and then performs subtraction as
              above.

       <, <=, >, and >=
              These are the comparison operators.  They can take operands of any type,  but  both
              operands  must  be  of  the  same  type.   The comparison operators return 1 if the
              comparison is true, or 0 if it is false.   Note  that  string  comparison  is  done
              following  the  lexical  ordering  of characters on your system, and that upper and
              lower case are distinct for these operators.

       ==, != == tests for equality, returning 1 if its operands are equal, and  0  if  they  are
              not.  != tests for inequality.

              If  the  operands  are not of the same type, == returns 0 and != returns 1.  Again,
              string comparisons are case-sensitive.

       &&     This is the logical AND operator.  Both of its operands must be of  the  same  type
              and  must not be STRING type.  Returns the second operand if both operands are non-
              zero.  Otherwise, returns a zero of the same type as the operands.

       ||     This is the logical OR operator.  Both of its operands must be of the same type and
              must not be of STRING type.  It returns the first operand that is non-zero; if both
              operands are zero, then returns a zero of the same type as the operands.

       NOTES

       If the result of an addition, subtraction or multiplication operation would not fit in a C
       "int"  type,  Remind  issues a "Number too high" error.  Unlike C, integer operations will
       not simply give the wrong answer in case of overflow.

       Operators of equal precedence are always  evaluated  from  left  to  right,  except  where
       parentheses  dictate  otherwise.   This is important, because the enhanced "+" operator is
       not necessarily associative.  For example:

            1 + 2 + "string" + 3 + 4  yields "3string34"
            1 + (2 + "string") + (3 + 4)  yields "12string7"
            12:59 + 1 + "test"  yields "13:00test"
            12:59 + (1 + "test")  yields "12:591test"

       The logical operators are not so-called short-circuit operators, as they are in  C.   Both
       operands are always evaluated.  Thus, an expression such as:

            (f!=0) && (100/f <= 3)

       will cause an error if f is zero.

       VARIABLES

       Remind allows you to assign values to variables.  The SET command is used as follows:

       SET var expr

       Var  is  the  name  of a variable.  It must start with a letter or underscore, and consist
       only of letters, digits and underscores.  Only the first 64 characters of a variable  name
       are  significant.   Variable names are not case sensitive; thus, "Afoo" and "afOo" are the
       same variable.  Examples:

            SET a 10 + (9*8)
            SET b "This is a test"
            SET mydir getenv("HOME")
            SET time 12:15
            SET date today()

       Note that variables themselves have no type.  They take on the type of whatever you  store
       in them.

       Variables set with SET or on the command-line with -ivar=expr have global scope.

       To delete a variable, use the UNSET command:

       UNSET var [var...]

       For example, to delete all the variables declared above, use:

            UNSET a b mydir time date

       SYSTEM VARIABLES

       In  addition to the regular user variables, Remind has several "system variables" that are
       used to query or control the operating state of Remind.  System  variables  are  available
       starting from version 03.00.07 of Remind.

       All  system  variables begin with a dollar sign '$'.  They can be used in SET commands and
       expressions just as regular variables can.  All system variables always hold values  of  a
       specified  type.   In  addition,  some system variables cannot be modified, and you cannot
       create new system variables.  System variables can be initialized on the command line with
       the  -i  option,  but  you  may need to quote them to avoid having the shell interpret the
       dollar sign.  System variable names are not case-sensitive.

       The following system variables are defined.  Those marked "read-only"  cannot  be  changed
       with  the  SET  command.   All  system variables hold values of type INT, unless otherwise
       specified.

       $AddBlankLines
              If set to 1 (the default), then Remind normally  prints  a  blank  line  after  the
              banner and each reminder.  (This can be suppressed by ending the reminder or banner
              with a single percent sign.)  If $AddBlankLines is set to 0, then Remind  does  not
              print  the  blank  line.  In this case, ending a reminder with % has no effect.  If
              you do want a blank line after a reminder, end it with %_ to insert a newline.

       $CalcUTC
              If 1 (the default), then Remind uses C library functions to calculate the number of
              minutes  between  local  and Universal Time Coordinated.  This affects astronomical
              calculations (sunrise() for example.)  If 0, then you must  supply  the  number  of
              minutes  between  local  and  Universal Time Coordinated in the $MinsFromUTC system
              variable.

       $CalMode (read-only)
              If non-zero, then the -c option was supplied on the command line.

       $Daemon (read-only)
              If the daemon mode -z was invoked, contains the number of minutes between  wakeups.
              If not running in daemon mode, contains 0.

       $DateSep
              This  variable  can  be  set  only  to  "/" or "-".  It holds the character used to
              separate portions of a date when Remind prints a DATE or DATETIME value.

       $DefaultColor
              This variable can be set to a string that has the  form  of  three  space-separated
              numbers.   Each  number must be an integer from 0 to 255, or all three numbers must
              be -1.  The default value of $DefaultColor is "-1 -1 -1", which suppresses  default
              coloring  of MSG-type reminders.  If you set $DefaultColor to any other value, then
              all MSG-, MSF- and CAL-type reminders are effectively converted into SPECIAL  COLOR
              reminders whose color value is specified by $DefaultColor.

              Unlike  other system variables, the value of $DefaultColor is not preserved between
              calendar iterations; rather, it is reset to  "-1  -1  -1"  at  the  start  of  each
              iteration.

       $DefaultPrio
              The  default priority assigned to reminders without a PRIORITY clause.  You can set
              this as required to adjust the priorities of blocks of reminders without having  to
              type priorities for individual reminders.  At startup, $DefaultPrio is set to 5000;
              it can range from 0 to 9999.

       $DefaultTDelta
              The default time delta used if no +N is given in an AT clause.  This is normally 0,
              but  can  be  set  with  the  -tt  option  or  explicitly  set  in your script.  If
              $DefaultDelta is non-zero, you can use an explicit delta of +0 in an AT  clause  to
              countermand the default delta.

       $DeltaOverride (read-only)
              If non-zero, corresponds to the n argument given to a -tn command-line option.

       $DontFork (read-only)
              If non-zero, then the -c option was supplied on the command line.

       $DontTrigAts (read-only)
              The number of times that the -a option was supplied on the command line.

       $DontQueue (read-only)
              If non-zero, then the -q option was supplied on the command line.

       $EndSent (STRING type)
              Contains  a  list  of  characters that end a sentence.  The MSF keyword inserts two
              spaces after these characters.   Initially,  $EndSent  is  set  to  ".!?"  (period,
              exclamation mark, and question mark.)

       $EndSentIg (STRING type)
              Contains  a  list  of characters that should be ignored when MSF decides whether or
              not to place two spaces after a sentence.  Initially, is  set  to  "'>)]}"+CHAR(34)
              (single-quote,  greater-than,  right  parenthesis,  right bracket, right brace, and
              double-quote.)

              For example, the default values work as follows:

                   MSF He said, "Huh! (Two spaces will follow this.)"  Yup.

              because the final parenthesis and quote are ignored (for the purposes  of  spacing)
              when they follow a period.

       $FirstIndent
              The number of spaces by which to indent the first line of a MSF-type reminder.  The
              default is 0.

       $FoldYear
              The standard Unix library functions may have difficulty dealing  with  dates  later
              than  2037.   If  this  variable is set to 1, then the UTC calculations "fold back"
              years later than 2037 before using the Unix library  functions.   For  example,  to
              find  out  whether or not daylight saving time is in effect in June, 2077, the year
              is "folded back" to 2010, because both years begin on a Monday, and both  are  non-
              leapyears.   The  rules  for daylight saving time are thus presumed to be identical
              for both years, and the Unix library functions can handle 2010.  By  default,  this
              variable is 0.  Set it to 1 if the sun or UTC functions misbehave for years greater
              than 2037.

       $FormWidth
              The maximum width of each line of text  for  formatting  MSF-type  reminders.   The
              default  is the width of the terminal in columns, minus 8, but clamped at a minimum
              of 20 and a maximum of 500.  If standard output is not a terminal, then the default
              is  72.If  an  MSF-type  reminder contains a word too long to fit in this width, it
              will not be truncated - the width limit will be ignored.

       $HushMode (read-only)
              If non-zero, then the -h option was supplied on the command line.

       $IgnoreOnce (read-only)
              If non-zero, then the -o option was  supplied  on  the  command  line,  or  a  date
              different  from  today's true date was supplied.  If non-zero, then ONCE directives
              will be ignored.

       $InfDelta (read-only)
              If non-zero, then the -t option was  supplied  on  the  command  line,  with  no  n
              argument.

       $IntMax (read-only)
              The  largest  representable  INT.   On  a machine with 32-bit signed integers using
              twos-complement representation, this will be 2147483647.

       $IntMin (read-only)
              The smallest representable INT.  On a machine with  32-bit  signed  integers  using
              twos-complement representation, this will be -2147483648.

       $Latitude (STRING type)
              The  latitude  of  your  location,  expressed  as a string that is a floating-point
              number.  Because Remind does not have a native  floating-point  type,  we  need  to
              express  it as a string.  $Latitude can range from "-90.0" to "90.0", with positive
              numbers representing points north of the equator and negative numbers  representing
              south.  Note that regardless of your locale, $Latitude is always interpreted in the
              "C" locale and as such, the decimal point must be a period (".").

       $Longitude (STRING type)
              The longitude of your location, expressed as a  string  that  is  a  floating-point
              number.   Because  Remind  does  not  have a native floating-point type, we need to
              express it as a string.  $Longitude  can  range  from  "-180.0"  to  "180.0",  with
              positive  numbers  representing  points east of the Greenwich Meridian and negative
              numbers representing west.  Note that regardless  of  your  locale,  $Longitude  is
              always  interpreted  in  the  "C"  locale  and as such, the decimal point must be a
              period (".").

              For example, the coordinates of  the  Statue  of  Liberty  in  New  York  City  are
              approximately set by:

                  SET $Latitude   "40.68933"
                  SET $Longitude "-74.04454"

       $LatDeg, $LatMin, $LatSec (DEPRECATED)
              These specify the latitude of your location.  $LatDeg can range from -90 to 90, and
              the others from -59 to 59.  Northern latitudes  are  positive;  southern  ones  are
              negative.   For southern latitudes, all three components should be negative.  These
              three variables are deprecated; you should use $Latitude instead.

       $Location (STRING type)
              This is a string specifying the name of your location.  It is usually the  name  of
              your  town  or  city.  It can be set to whatever you like, but good style indicates
              that it should be kept consistent with the latitude and longitude system variables.

       $LongDeg, $LongMin, $LongSec (DEPRECATED)
              These specify the longitude of your location.  $LongDeg can range from -180 to 180.
              Western  longitudes  are  positive; eastern ones are negative.  Note that all three
              components should have the same sign: All positive for western longitudes  and  all
              negative  for  eastern  longitudes.  Note that for historical reasons, the sign for
              longitude is different from the usual convention!  If you  find  the  longitude  of
              your location from a search engine, you will most likely need to invert the sign to
              have it work correctly with Remind.  These  three  variables  are  deprecated;  you
              should  use  $Longitude  instead.   Note  also  that  $Longitude  uses the standard
              convention of negative for western longitudes and positive for eastern ones.

              The latitude and longitude information is required for the functions sunrise()  and
              sunset().   Default  values can be compiled into Remind, or you can SET the correct
              values at the start of your reminder scripts.

              Note that setting  any  of  $LongDec,  $LongMin  and  $LongSec  updates  $Longitude
              correspondingly,  and  setting  $Longitude updates $LongDeg, $LongMin and $LongSec.
              Similar rules apply to $Latitude, $LatDeg, $LatMin and $LatSec.

       $MaxLateMinutes
              This variable controls how Remind reacts to a computer  being  suspended  and  then
              woken.   Normally,  if  a timed reminder is queued and then the computer suspended,
              and then the computer is woken after the timed reminder's trigger time, Remind will
              triger the timer anyway, despite the fact that the trigger time has already passed.

              If  you  set  $MaxLateMinutes to a non-zero integer between 1 and 1440, then Remind
              will not trigger a timed reminder whose trigger time is more  than  $MaxLateMinutes
              minutes in the past.

              Note  that  Remind  uses the value of $MaxLateMinutes that is in effect when it has
              finished reading the reminder file and puts itself in the  background.   Generally,
              you  should  set $MaxLateMinutes once near the beginning of the file and not change
              it after that.

       $MaxSatIter
              The maximum number of iterations for the SATISFY clause (described later.)  Must be
              at least 10.

       $MaxStringLen
              A limit on the longest string that Remind will allow you to create.  The default is
              65535.  If you set $MaxStringLen to 0 or to -1,  then  remind  will  allow  you  to
              create  arbitrarily-long  strings, at least until it runs out of memory.  We do not
              recommend setting $MaxStringLen to 0 or -1 because it is very easy  to  write  code
              that DOSes Remind in that case.

       $MinsFromUTC
              The  number  of  minutes  between  Universal  Time  Coordinated and local time.  If
              $CalcUTC is non-zero, this is calculated upon startup of  Remind.   Otherwise,  you
              must  set  it  explicitly.   If  $CalcUTC is zero, then $MinsFromUTC is used in the
              astronomical calculations.  You must adjust it for daylight saving  time  yourself.
              Also,  if you want to initialize $MinsFromUTC using the -i command-line option, you
              must also set $CalcUTC to 0 with the -i option.

       $NextMode (read-only)
              If non-zero, then the -n option was supplied on the command line.

       $MaxFullOmits (read-only)
              The maximum number of full OMITs allowed (a compiled-in constant.)

       $MaxPartialOmits (read-only)
              The maximum number of partial OMITs allowed (a compiled-in constant.)

       $NumFullOmits (read-only)
              The number of full OMITs in the current OMIT context.

       $NumPartialOmits (read-only)
              The number of partial OMITs in the current OMIT context.

       $NumQueued (read-only)
              Contains the number of reminders queued so far for background timed triggering.

       $NumTrig (read-only)
              Contains the number of reminders triggered for the current date.  One use for  this
              variable  is  as  follows:   Suppose  you  wish to shade in the box of a PostScript
              calendar whenever a holiday is triggered.  You could save the value of $NumTrig  in
              a  regular  variable prior to executing a block of holiday reminders.  If the value
              of $NumTrig after the holiday block is greater than the saved value, then at  least
              one holiday was triggered, and you can execute the command to shade in the calendar
              box.  (See the section "Calendar Mode".)

              Note that $NumTrig is affected only by REM commands; triggers in IFTRIG commands do
              not affect it.

       $ParseUntriggered
              A  flag indicating whether or not Remind should fully parse REM statements that are
              not triggered.  0 means to skip parsing them and 1 (the  default)  means  to  parse
              them.

              For example, if we have the following REM statement:

                          REM 2020-01-01 MSG ["bad_expression" * 2]

              Then by default, Remind will fully parse the line and issue a "Type mismatch" error
              even if the reminder is not triggered.  However, if $ParseUntriggered is set to  0,
              then  Remind  will  not  issue the error except on 2020-01-01, when the reminder is
              triggered.

              Setting $ParseUntriggered to 0 may in some cases slightly improve  performance,  at
              the risk of not catching errors until a reminder is triggered.

       $PrefixLineNo (read-only)
              If non-zero, then the -l option was supplied on the command line.

       $PSCal (read-only)
              If non-zero, then the -p option was supplied on the command line.

       $RunOff (read-only)
              If non-zero, the RUN directives are disabled.

       $SimpleCal (read-only)
              Set  to  a  non-zero  value  if  either  of  the  -p or -s command-line options was
              supplied.

       $SortByDate (read-only)
              Set to 0 if no -g option is used, 1 if sorting by date in ascending order, or 2  if
              sorting by date in descending order.

       $SortByPrio (read-only)
              Set to 0 if no -g option is used, 1 if sorting by priority in ascending order, or 2
              if sorting by priority in descending order.

       $SortByTime (read-only)
              Set to 0 if no -g option is used, 1 if sorting by time in ascending order, or 2  if
              sorting by time in descending order.

       $SubsIndent
              The  number of spaces by which all lines (except the first) of an MSF-type reminder
              should be indented.  The default is 0.

       $SuppressLRM
              Normally, when Remind is run with the -c option in a UTF-8 locale, it emits a left-
              to-right  mark  sequence  after  printing  day  names or reminders.  Some terminals
              render this incorrectly, so you can use:

                  SET $SuppressLRM 1

              at the top of your reminder file to suppress the LRM sequences, or you  can  invoke
              Remind with the option '-i$SuppressLRM=1'.

       $SysInclude (read-only, STRING type)
              A  directory  path  containing  standard reminder scripts.  Currently, Remind ships
              with some standard holiday files and language packs.  The value of  $SysInclude  is
              "/usr/share/remind" on this installation.

       $T (read-only, DATE type)
              Exactly equivalent to trigdate().  (See BUILT-IN FUNCTIONS.)

       $Td (read-only)
              Equivalent to day(trigdate()).

       $Tm (read-only)
              Equivalent to monnum(trigdate()).

       $Tw (read-only)
              Equivalent to wkdaynum(trigdate()).

       $Ty (read-only)
              Equivalent to year(trigdate()).

       $TimeSep
              This  variable  can  be  set  only  to  ":" or ".".  It holds the character used to
              separate portions of a time when Remind prints a TIME or DATETIME value.

       $UntimedFirst (read-only)
              Set to 1 if the -g option is used with a fourth sort character of  "d";  set  to  0
              otherwise.

       $U (read-only, DATE type)
              Exactly equivalent to today().  (See BUILT-IN FUNCTIONS.)

       $Ud (read-only)
              Equivalent to day(today()).

       $Um (read-only)
              Equivalent to monnum(today()).

       $Uw (read-only)
              Equivalent to wkdaynum(today()).

       $Uy (read-only)
              Equivalent to year(today()).

       $UseVTColors (read-only)
              Set to 1 if the -@ or -cc options were used; 0 otherwise.

       $UseBGVTColors (read-only)
              Set to 1 if the -@,,1 option was used; 0 otherwise.

       $Use256Colors (read-only)
              Set to 1 if the -@1 option was used; 0 otherwise.

       $UseTrueColors (read-only)
              Set to 1 if the -@2 option was used; 0 otherwise.

       $TerminalBackground (read-only)
              Returns  -1  if  the terminal background color could not be determined, 0 if it was
              found to be dark (or was specified as dark with the -@,0 option) or  1  if  it  was
              found  to  be  light  (or  specified  as light with the -@,1 option.)  The terminal
              background is considered to be "dark" if the average of the  red,  green  and  blue
              components is at most 85 out of 255, and if the maximum of any component is at most
              128 out of 255.

       Note:  If any of the calendar modes are in effect, then the values of $Daemon,  $DontFork,
       $DontTrigAts,  $DontQueue,  $HushMode,  $IgnoreOnce,  $InfDelta,  and  $NextMode  are  not
       meaningful.

       BUILT-IN FUNCTIONS

       Remind has a plethora of built-in functions.  The syntax for a function call is  the  same
       as  in C - the function name, followed a comma-separated list of arguments in parentheses.
       Function names are not case-sensitive.  If a function  takes  no  arguments,  it  must  be
       followed  by "()" in the function call.  Otherwise, Remind will interpret it as a variable
       name, and probably not work correctly.

       In the descriptions below, short forms  are  used  to  denote  acceptable  types  for  the
       arguments.   The  characters "i", "s", "d", "t" and "q" denote INT, STRING, DATE, TIME and
       DATETIME arguments, respectively.  If an  argument  can  be  one  of  several  types,  the
       characters are concatenated.  For example, "di_arg" denotes an argument that can be a DATE
       or an INT.  "x_arg" denotes an argument that can be of any type.  The type of the argument
       is followed by an underscore and an identifier naming the argument.

       The built-in functions are:

       abs(i_num)
              Returns the absolute value of num.

       access(s_file, si_mode)
              Tests the access permissions for the file file.  Mode can be a string, containing a
              mix of the characters  "rwx"  for  read,  write  and  execute  permission  testing.
              Alternatively, mode can be a number as described in the UNIX access(2) system call.
              The function returns 0 if the file can be accessed with the specified mode, and  -1
              otherwise.

       adawn([dq_date])
              Returns the time of "astronomical dawn" on the specified date.  If date is omitted,
              defaults to today().  If a datetime object is supplied, only the date component  is
              used.

       adusk([dq_date])
              Returns  the  time  of  "astronomical  twilight" on the specified date.  If date is
              omitted, defaults to today().

       ampm(tq_time [,s_am [,s_pm]])
              Returns a STRING that is the result of converting time (which is either a TIME or a
              DATETIME  object)  to  "AM/PM"  format.   The  optional arguments am and pm are the
              strings to append in the AM and PM case, respectively; they  default  to  "AM"  and
              "PM".   The function obeys the system variables $DateSep, $TimeSep and $DateTimeSep
              when formatting its output.  For example:

                      ampm(0:22)                 returns "12:22AM"
                      ampm(17:45, "am", "pm")    returns "5:45pm"
                      ampm('2020-03-14@21:34')   returns "2020-03-14@9:34PM"

       ansicolor(i_red, i_green, i_blue [,i_bg [,i_clamp]])
              Returns a STRING that contains an ANSI escape sequence for  changing  the  terminal
              text  color.   The  parameters  red,  green  and  blue  are  integers from 0 to 255
              specifying the value of the respective color component.  As  a  special  case,  all
              three values can be -1, in which case the ANSI sequence "ESC[0m" is returned, which
              resets all text attributes to normal.

              The string returned by ansicolor depends on the color mode that Remind  is  running
              in,  as  specified  by the -@ option.  If color mode is not enabled, then ansicolor
              always returns the empty string.  Otherwise, it returns the  escape  sequence  that
              best approximates the color according to the -@ color mode.

              The optional bg argument is either 0 or 1.  If 0 (the default), then the foreground
              color is set.  If 1, then the background color  is  set.   Note  that  setting  the
              background color only works in 256-color or true-color mode.

              The  optional clamp argument is either 0 or 1.  If 0 (the default), then colors are
              not adjusted based on the terminal background color.  If 1, then Remind attempts to
              adjust  dark  or  bright  colors  so they have enough contrast to be visible in the
              terminal.

              The first three arguments may alternatively be specified as a string consisting  of
              three space-separated numbers, as in this example: "128 128 0"

              As  a  special case, ansicolor("") is equivalent to ansicolor(-1,-1,-1) and returns
              the ANSI sequence to reset all text attributes to normal.

              Note that inserting ANSI color sequences in  calendar  mode  will  produce  garbled
              results.   Therefore,  we  recommend defining functions such as the ones below that
              return the empty string in calendar mode:

                      IF $CalMode
                          FSET fg(r,g,b) ""
                          FSET bg(r,g,b) ""
                      ELSE
                          FSET fg(r,g,b) ansicolor(r,g,b)
                          FSET bg(r,g,b) ansicolor(r,g,b,1)
                      ENDIF
                      REM [fg(255,0,0)][bg(64,64,64)]Red on Gray[fg(-1,-1,-1)] in normal mode
                      REM SPECIAL COLOR 0 255 0 Green in normal and calendar mode

              If you use the ansicolor function, don't forget to reset the color back  to  normal
              with ansicolor(-1,-1,-1) or subsequent reminders will continue to be colored.

       args(s_fname)
              Returns  the number of arguments expected by the user-defined function fname, or -1
              if no such user-defined function exists.  Note that  this  function  examines  only
              user-defined  functions,  not  built-in  functions.   Its  main use is to determine
              whether or not a particular user-defined function has been defined previously.  The
              args() function is available only in versions of Remind from 03.00.04 and up.

       asc(s_string)
              Returns  an  INT  that  is  the  ASCII code of the first character in string.  As a
              special case, asc("") returns 0.  For UTF-8 strings, this  will  return  the  UTF-8
              byte  with  which the string begins, which is not likely to be very useful (and may
              indeed be negative on machines where char is a signed type.)

       baseyr()
              Returns the "base year" that was compiled into Remind (normally 1990.)   All  dates
              are stored internally as the number of days since 1 January of baseyr().

       char(i_i1 [,i_i2...])
              This function can take any number of INT arguments.  It returns a STRING consisting
              of the bytes specified by the arguments.   It  is  easy  to  create  invalid  UTF-8
              sequences; char does not check for this.  Note that none of the arguments can be 0,
              unless there is only one argument.  As a special case, char(0) returns "".

       choose(i_index, x_arg1 [,x_arg2...])
              Choose must take at least two arguments, the first of which is an INT.  If index is
              n,  then  the  nth  subsequent argument is returned.  If index is less than 1, then
              arg1 is returned.  If index is greater than the  number  of  subsequent  arguments,
              then the last argument is returned.  Examples:

                 choose(0, "foo", 1:13, 1000) returns "foo"
                 choose(1, "foo", 1:13, 1000) returns "foo"
                 choose(2, "foo", 1:13, 1000) returns 1:13
                 choose(3, "foo", 1:13, 1000) returns 1000
                 choose(4, "foo", 1:13, 1000) returns 1000
              Note that all arguments to choose() are always evaluated.

       coerce(s_type, x_arg)
              This  function  converts arg to the specified type, if such conversion is possible.
              Type  must  be  one  of  "INT",  "STRING",  "DATE",  "TIME"  or  "DATETIME"  (case-
              insensitive).  The conversion rules are as follows:

              If arg is already of the type specified, it is returned unchanged.

              If  type  is  "STRING", then arg is converted to a string consisting of its printed
              representation.

              If type is "DATE", then an INT arg is converted by interpreting it as the number of
              days  since 1 January baseyr().  A STRING arg is converted by attempting to read it
              as if it were a printed date.  A DATETIME is converted to a date  by  dropping  the
              time component.  A TIME arg cannot be converted to a date.

              If type is "TIME", then an INT arg is converted by interpreting it as the number of
              minutes since midnight.  A STRING arg is converted by attempting to read it  as  if
              it  were  a  printed  time.  A DATETIME is converted to a time by dropping the date
              component.  A DATE arg cannot be converted to a time.

              If type is "DATETIME", then an INT arg is  converted  by  interpreting  it  as  the
              number  of  minutes  since  midnight, 1 January baseyr().  A STRING is converted by
              attempting to read it as if it were a printed  datetime.   Other  types  cannot  be
              converted to a datetime.

              If  type  is  "INT", then DATE, TIME and DATETIME arguments are converted using the
              reverse of procedures described above.  A STRING arg is converted by parsing it  as
              an integer.

       columns([s_arg])
              If  called with no arguments, columns() behaves as follows: If standard output is a
              TTY, returns the width of the terminal in columns.  If standard  output  is  not  a
              TTY,  attempts  to  open  "/dev/tty"  to  obtain the terminal size.  If this fails,
              returns -1.

              If called with a single string argument, columns(str) returns the number of columns
              str  will  occupy  if  printed to a terminal.  ANSI color-changing sequences occupy
              zero columns whereas some Unicode  characters  occupy  two  columns.   columns(str)
              takes  all  of that into account.  Note that if Remind was compiled without Unicode
              support, columns(str) returns a type mismatch error.

       current()
              Returns the current date and time as a DATETIME object.  This  may  be  the  actual
              date and time, or may be the date and time supplied on the command line.

       date(i_y, i_m, i_d)
              The  date()  function returns a DATE object with the year, month and day components
              specified by y, m and d.

       datepart(dq_datetime)
              Returns a DATE object representing the date portion of datetime.

       datetime(args)
              The datetime() function can take anywhere from two to five  arguments.   It  always
              returns a DATETIME generated from its arguments.

              If you supply two arguments, the first must be a DATE and the second a TIME.

              If  you  supply  three arguments, the first must be a DATE and the second and third
              must be INTs.  The second and third arguments are interpreted as hours and  minutes
              and converted to a TIME.

              If  you  supply  four  arguments,  the first three must be INTs, interpreted as the
              year, month and day.  The fourth argument must be a TIME.

              Finally, if you supply five arguments, they must all be INTs and are interpreted as
              year, month, day, hour and minute.

       dawn([dq_date])
              Returns  the  time  of  "civil  dawn"  on  the specified date.  If date is omitted,
              defaults to today().  If a datetime object is supplied, only the date component  is
              used.

       day(dq_date)
              This  function  takes a DATE or DATETIME as an argument, and returns an INT that is
              the day-of-month component of date.

       daysinmon(i_m, i_y)
              Returns the number of days in month m (1-12) of the year y.

       defined(s_var)
              Returns 1 if the variable named by var is defined, or 0 if it is not.
              Note that defined() takes a STRING argument;  thus,  to  check  if  variable  X  is
              defined, use:

                        defined("X")

              and not:

                        defined(X)

              The  second  example  will attempt to evaluate X, and will return an error if it is
              undefined or not of type STRING.

       dosubst(s_str [,d_date [,t_time]]) or dosubst(s_str [,q_datetime])
              Returns a STRING that is the result of passing str through the substitution  filter
              described  earlier.   The  parameters  date  and  time  (or datetime) establish the
              effective trigger date and time used by the substitution filter.  If date and  time
              are omitted, they default to today() and now().

              Note  that  if  str does not end with "%", a newline character will be added to the
              end of the result.  Also, calling dosubst() with a date that is in the past  (i.e.,
              if date < today()) will produce undefined results.

              Dosubst() is only available starting from version 03.00.04 of Remind.

       dusk([dq_date])
              Returns  the  time  of "civil twilight" on the specified date.  If date is omitted,
              defaults to today().

       easterdate([dqi_arg])
              If arg is an INT, then returns the date of Easter Sunday for  the  specified  year.
              If arg is a DATE or DATETIME, then returns the date of the next Easter Sunday on or
              after arg.  (The time component of a datetime is ignored.)  If arg is omitted, then
              it defaults to today().

              Note  that  easterdate  computes the Western Easter.  For the Orthodox Easter date,
              see orthodoxeaster.

       evaltrig(s_trigger [,dq_start])
              Evaluates trigger as if it were a REM or IFTRIG trigger specification  and  returns
              the  trigger date as a DATE (or as a DATETIME if there is an AT clause.)  Returns a
              negative INT if no trigger could be computed.

              Normally, evaltrig finds a trigger date on or after today.  If you supply the start
              argument, then it scans starting from there.

              For example, the expression:

                evaltrig("Mon 1", '2008-10-07')

              returns  '2008-11-03', since that is the first date on or after 7 October 2008 that
              satisfies "Mon 1".

              If you want to see how many days it is from the first Monday in  October,  2008  to
              the first Monday in November, 2008, use:

                evaltrig("Mon 1", '2008-11-01') - evaltrig("Mon 1", '2008-10-01')

              and  the  answer  is  28.   The trigger argument to evaltrig can have all the usual
              trigger clauses (OMIT, AT, SKIP,  etc.)  but  cannot  have  a  SATISFY,  MSG,  etc.
              reminder-type clause.

       filedate(s_filename)
              Returns  the  modification  date  of  filename.  If filename does not exist, or its
              modification date is before the year  baseyr(),  then  1  January  of  baseyr()  is
              returned.

       filedatetime(s_filename)
              Returns the modification date and time of filename.  If filename does not exist, or
              its modification date is before the year baseyr(),  then  midnight,  1  January  of
              baseyr() is returned.

       filedir()
              Returns  the directory that contains the current file being processed.  It may be a
              relative or absolute pathname, but is guaranteed  to  be  correct  for  use  in  an
              INCLUDE command as follows:

                 INCLUDE [filedir()]/stuff

              This  includes  the  file  "stuff"  in the same directory as the current file being
              processed.  Note that this workaround is no longer necessary because DO stuff  will
              achieve the same goal.

              Note  that  if  the currently-processing reminders file was specified as a symbolic
              link, then filedir() returns the directory containing the symbolic link and not the
              directory  containing  the  target  of  the  symbolic link.  You should avoid using
              symbolic links to files unless both the symbolic link and its target happen  to  be
              in the same directory.

       filename()
              Returns  (as  a  STRING)  the  name  of the current file being processed by Remind.
              Inside included files, returns the name of the included file.

       getenv(s_envvar)
              Similar to the getenv(2) system call.  Returns a string representing the  value  of
              the  specified environment variable.  Returns "" if the environment variable is not
              defined.  Note  that  the  names  of  environment  variables  are  generally  case-
              sensitive; thus, getenv("HOME") is not the same as getenv("home").

       hebdate(i_day, s_hebmon [,idq_yrstart [,i_jahr [,i_aflag]]])
              Support for Hebrew dates - see the section "THE HEBREW CALENDAR"

       hebday(dq_date)
              Support for Hebrew dates - see the section "THE HEBREW CALENDAR"

       hebmon(dq_date)
              Support for Hebrew dates - see the section "THE HEBREW CALENDAR"

       hebyear(dq_date)
              Support for Hebrew dates - see the section "THE HEBREW CALENDAR"

       hour(tq_time)
              Returns the hour component of time.

       htmlescape(s_str)
              Returns  a  modified copy of str where "<" is replaced with "&lt;"; ">" is replaced
              with "&gt;" and "&" is replaced with "&amp;"

       htmlstriptags(s_str)
              Returns a modified copy of str where HTML tags are  stripped  out.   The  stripping
              algorithm  is  fairly  naive;  the  function  starts  stripping  characters when it
              encounters a "<" and it stops stripping when it encounters a ">".

       iif(si_test1, x_arg1, [si_test2, x_arg2,...], x_default)
              If test1 is not zero or the null string, returns arg1.  Otherwise, if test2 is  not
              zero or the null string, returns arg2, and so on.  If all of the test arguments are
              false, returns default.  Note  that  all  arguments  are  always  evaluated.   This
              function  accepts  an odd number of arguments - note that prior to version 03.00.05
              of Remind, it accepted 3 arguments  only.   The  3-argument  version  of  iif()  is
              compatible with previous versions of Remind.

       index(s_search, s_target [,i_start)
              Returns  an  INT  that  is  the location of target in the string search.  The first
              character of a string is numbered 1.  If target does not exist in search, then 0 is
              returned.

              The  optional  parameter  start  specifies the position in search at which to start
              looking for target.

       isany(arg1 [,arg2, ..., argN]);
              Returns 1 if the first argument arg1 is equal to any of  the  subsequent  arguments
              arg2  through  argN;  returns  0 otherwise.  Also returns 0 if called with only one
              argument.

              As an example, the following two expressions are equivalent:

                      (a == b) || (a == c) || (a == d) || (a == e)

                      isany(a, b, c, d, e)

       isdst([d_date [,t_time]]) or isdst(q_datetime)
              Returns a positive number if daylight saving time is in  effect  on  the  specified
              date and time.  Date defaults to today() and time defaults to midnight.

              Note  that  this  function is only as reliable as the C run-time library functions.
              It is available starting with version 03.00.07 of Remind.

       isleap(idq_arg)
              Returns 1 if arg is a leap year, and 0 otherwise.  Arg  can  be  an  INT,  DATE  or
              DATETIME  object.   If  a  DATE or DATETIME is supplied, then the year component is
              used in the test.

       isomitted(dq_date)
              Returns 1 if date is omitted, given the current global  OMIT  context.   Returns  0
              otherwise.  (If a datetime is supplied, only the date part is used.)  Note that any
              local OMIT or OMITFUNC clauses are not taken into account by this function.

       language()
              Returns a STRING naming the language supported by Remind.  (See "SUPPORT FOR  OTHER
              LANGUAGES")  By  default,  Remind  is compiled to support English messages, so this
              function returns "English".  For other languages, this  function  will  return  the
              English  name of the language (e.g. "German") Note that language() is not available
              in versions of Remind prior to 03.00.02.

       localtoutc(q_datetime)
              Given a DATETIME object interpreted in the  local  time  zone,  return  a  DATETIME
              object that expresses the same time in UTC.

       lower(s_string)
              Returns a STRING with all upper-case characters in string converted to lower-case.

       max(x_arg1 [,x_arg2...)
              Can take any number of arguments, and returns the maximum.  The arguments can be of
              any type, but must all be of the same type.   They  are  compared  as  with  the  >
              operator.

       min(x_arg1 [,x_arg2...)
              Can take any number of arguments, and returns the minimum.  The arguments can be of
              any type, but must all be of the same type.   They  are  compared  as  with  the  <
              operator.

       minsfromutc([d_date [,t_time]]) or minsfromutc(q_datetime)
              Returns  the  number  of  minutes from Universal Time Coordinated (formerly GMT) to
              local time on the specified date and time.   Date  defaults  to  today()  and  time
              defaults  to  midnight.   If  local  time  is  before  UTC, the result is negative.
              Otherwise, the result is positive.

              Note that this function is only as reliable as the C  run-time  library  functions.
              It is available starting with version 03.00.07 of Remind.

       minute(tq_time)
              Returns the minute component of time.

       mon(dqi_arg)
              If arg is of DATE or DATETIME type, returns a string that names the month component
              of the date.  If arg is an INT from 1 to 12, returns a string that names the month.

       monnum(dq_date)
              Returns an INT from 1 to 12, representing the month component of date.

       moondate(i_phase [,d_date [,t_time]]) or moondate(i_phase, q_datetime)
              This function returns the date of the first occurrence of the phase  phase  of  the
              moon on or after date and time.  Phase can range from 0 to 3, with 0 signifying new
              moon, 1 first quarter, 2 full moon, and 3 third quarter.  If date  is  omitted,  it
              defaults to today().  If time is omitted, it defaults to midnight.

              For example, the following returns the date of the next full moon:

                        SET fullmoon moondate(2)

       moontime(i_phase [,d_date [,t_time]]) or moontime(i_phase, q_datetime)
              This  function  returns  the time of the first occurrence of the phase phase of the
              moon on or after date and time.  Phase can range from 0 to 3, with 0 signifying new
              moon,  1  first  quarter, 2 full moon, and 3 third quarter.  If date is omitted, it
              defaults to today().  If time is omitted, it defaults to midnight.   Moontime()  is
              intended  to be used in conjunction with moondate().  The moondate() and moontime()
              functions are accurate to within a couple of minutes of the times in "Old  Farmer's
              Almanac" for Ottawa, Ontario.

              For example, the following returns the date and time of the next full moon:

                        MSG Next full moon at [moontime(2)] on [moondate(2)]

       moondatetime(i_phase [,d_date [,t_time]]) or moondatetime(i_phase, q_datetime)
              This function is similar to moondate and moontime, but returns a DATETIME result.

       moonphase([d_date [,t_time]]) or moonphase(q_datetime)
              This  function  returns  the  phase  of the moon on date and time, which default to
              today() and midnight, respectively.  The returned value is an  integer  from  0  to
              359, representing the phase of the moon in degrees.  0 is a new moon, 180 is a full
              moon, 90 is first-quarter, etc.

       ndawn([dq_date])
              Returns the time of "nautical dawn" on the specified date.   If  date  is  omitted,
              defaults  to today().  If a datetime object is supplied, only the date component is
              used.

       ndusk([dq_date])
              Returns the time of "nautical twilight" on the specified date.  If date is omitted,
              defaults to today().

       nonomitted(dq_start, dq_end [, i_step] [,s_wkday...])
              This  function  returns  the  number of non-omitted days between start and end.  If
              start is non-omitted, then it is counted.  end is never counted.

              Note that if end is less than start, the  arguments  are  effectively  swapped,  so
              counting always begins from the older date.

              If  the  third argument to nonomitted is an INT, then it must be greater than zero,
              and is consider to be the  step  by  which  nonomitted  counts.   For  example  the
              following expression:

                      nonomitted('2023-07-01', '2023-07-29', 7)

              returns  the  number  of  non-omitted  Saturdays  from  2023-07-01  up  to (but not
              including) 2023-07-29.  (Both 2023-07-01 and 2023-07-29 are Saturdays.)

              If no step argument is supplied, then a step of 1 is used.

              In addition to using the global OMIT context, you can supply  additional  arguments
              that  are  names  of  weekdays to be omitted.  However, in a REM command, any local
              OMITFUNC clause is not taken into account by this function.

              For example, the following line sets a to 11 (assuming no global OMITs):

                   set a nonomitted('2007-08-01', '2007-08-16', "Sat", "Sun")

              because Thursday, 16 August 2007 is the 11th working day (not counting Saturday and
              Sunday) after Wednesday, 1 August 2007.

              nonomitted  has various uses.  For example, many schools run on a six-day cycle and
              the day number is not incremented on holidays.  Suppose the school year starts with
              Day  1  on  4  September  2007.  The following reminder will label day numbers in a
              calendar:

                 IF today() >= '2007-09-04'
                     set daynum nonomitted('2007-09-04', today(), "Sat", "Sun")
                     REM OMIT SAT SUN SKIP CAL Day [(daynum % 6) + 1]
                 ENDIF

              Obviously, the answer you get from nonomitted depends on the global  OMIT  context.
              If you use movable OMITs, you may get inconsistent results.

              Here  is  a  more  complex  use  for nonomitted.  My garbage collection follows two
              interleaved 14-day cycles: One Friday, garbage and paper  recycling  ("Black  Box")
              are  collected.   The  next  Friday, garbage and plastic recycling ("Blue Box") are
              collected.  If any of Monday-Friday is a holiday, collection is delayed  until  the
              Saturday.  Here's a way to encode these rules:

                 fset _garbhol(x) wkdaynum(x) == 5 && nonomitted(x-4, x+1) < 5
                 REM 12 November 1999 *14 AFTER OMITFUNC _garbhol MSG Black Box
                 REM 19 November 1999 *14 AFTER OMITFUNC _garbhol MSG Blue Box

              Here's  how  it works:  The _garbhol(x) user-defined function returns 1 if and only
              if (1) x is a Friday and (2) there is at least one OMITted day  from  the  previous
              Monday up to and including the Friday.

              The  first  REM  statement  sets  up the 14-day black-box cycle.  The AFTER keyword
              makes it move collection to the Saturday if _garbhol returns  1.   The  second  REM
              statement sets up the 14-day blue-box cycle with a similar adjustment made by AFTER
              in conjunction with _garbhol.

       now()  Returns the current system time, as a TIME type.  This may be the actual time, or a
              time supplied on the command line.

       ord(i_num)
              Returns  a  string  that  is  the  ordinal number num.  For example, ord(2) returns
              "2nd", and ord(213) returns "213th".

       orthodoxeaster([dqi_arg])
              If arg is an INT, then returns the date of Orthodox Easter Sunday for the specified
              year.   If  arg  is  a DATE or DATETIME, then returns the date of the next Orthodox
              Easter Sunday on or after arg.  (The time component of a datetime is ignored.)   If
              arg is omitted, then it defaults to today().

              Note  that  orthodoxeaster  computes  the  Orthodox Easter.  For the Western Easter
              date, see easterdate.

       ostype()
              Returns "UNIX".  Remind used to run on OS/2 and MS-DOS, but does not any longer.

       pad(x_arg, s_padstr, i_len [, i_right])
              Converts the first argument arg to a string if necessary, and then if it is shorter
              than  len  characters,  pads  to  to len characters using as many copies (including
              partial copies) of padstr as necessary.  By default, the string is left-padded, but
              if right is supplied and non-zero, the string will be right-padded.

              Here are some examples:

                  pad(3, "0", 2)        -->  "03"
                  pad(465, "0", 2)      -->  "465"
                  pad("foo", " ", 5)    -->  "  foo"
                  pad("foo", " ", 5, 1) -->  "foo  "
                  pad("foo", "bar", 11) -->  "barbarbafoo"

       plural(i_num [,s_str1 [,s_str2]])
              Can  take from one to three arguments.  If one argument is supplied, returns "s" if
              num is not 1, and "" if num is 1.

              If two arguments are supplied, returns str1 + "s" if  num  is  not  1.   Otherwise,
              returns str1.

              If three arguments are supplied, returns str1 if num is 1, and str2 otherwise.

       psmoon(i_phase [,i_size [,s_note [,i_notesize]]])
              [DEPRECATED]  Returns  a STRING consisting of PostScript code to draw a moon in the
              upper-left hand corner of the calendar box.  Phase specifies the phase of the moon,
              and  is  0  (new  moon), 1 (first quarter), 2 (full moon) or 3 (third quarter).  If
              size is specified, it controls the radius of the moon  in  PostScript  units  (1/72
              inch.)   If  it is not specified or is negative, the size of the day-number font is
              used.

              For example, the  following  four  lines  place  moon  symbols  on  the  PostScript
              calendar:

                        REM [moondate(0)] PS [psmoon(0)]
                        REM [moondate(1)] PS [psmoon(1)]
                        REM [moondate(2)] PS [psmoon(2)]
                        REM [moondate(3)] PS [psmoon(3)]

              If  note  is specified, the text is used to annotate the moon display.  The font is
              the same font used for calendar entries.  If notesize is given,  it  specifies  the
              font  size to use for the annotation, in PostScript units (1/72 inch.)  If notesize
              is not given, it defaults to the size used for calendar entries.  (If you  annotate
              the  display,  be  careful not to overwrite the day number -- Remind does not check
              for this.)  For example, if you want the time of each new moon displayed, you could
              use this in your reminder script:

                   REM [moondate(0)] PS [psmoon(0, -1, moontime(0)+"")]

              Note how the time is coerced to a string by concatenating the null string.

       psshade(i_gray) or psshade(i_red, i_green, i_blue)
              [DEPRECATED]  Returns  a  STRING  that  consists  of PostScript commands to shade a
              calendar box.  Num can range from 0 (completely black) to 100  (completely  white.)
              If  three arguments are given, they specify red, green and blue intensity from 0 to
              100.  Here's an example of how to use this:

                        REM Sat Sun PS [psshade(95)]

              The above command emits PostScript code to lightly shade the boxes for Saturday and
              Sunday in a PostScript calendar.

              Note  that  psmoon  and  psshade are deprecated; instead you should use the SPECIAL
              SHADE and SPECIAL MOON reminders as described in "Out-of-Band Reminders."

       realcurrent()
              Returns (as a DATETIME) the true date and time of day as provided by the  operating
              system.   This is in contrast to current(), which may return a time supplied on the
              command line.

       realnow()
              Returns the true time of day as provided by  the  operating  system.   This  is  in
              contrast to now(), which may return a time supplied on the command line.

       realtoday()
              Returns  the  date  as  provided  by  the operating system.  This is in contrast to
              Remind's concept of "today", which may be changed if  it  is  running  in  calendar
              mode, or if a date has been supplied on the command line.

       rows() If  standard  output  is  a  TTY,  returns  the height of the terminal in rows.  If
              standard output is not a TTY, attempts to open "/dev/tty" to  obtain  the  terminal
              size.  If this fails, returns -1.

       sgn(i_num)
              Returns -1 if num is negative, 1 if num is positive, and 0 if num is zero.

       shell(s_cmd [,i_maxlen])
              Executes  cmd  as  a system command, and returns the first 511 characters of output
              resulting from cmd.  Any whitespace character in  the  output  is  converted  to  a
              space.   Note  that if RUN OFF has been executed, or the -r command-line option has
              been used, shell() will result in an error, and cmd will not be executed.

              If maxlen is specified, then shell() returns the first maxlen characters of  output
              (rather  than the first 511).  If maxlen is specified as a negative number, then it
              defaults to the value of the system variable $MaxStringLen.

       shellescape(s_str)
              Returns str with all shell metacharacters such as " ",  "*",  etc  escaped  with  a
              backslash.  For example:

               SET a shellescape("a b*? c&d$e")

              will set a to:

               "a\ b\*\?\ c\&d\$e"

       slide(d_start, i_amt [, i_step] [,s_wkday...])
              This  function  is  the inverse of nonomitted.  It adds amt (which can be negative)
              chunks of step days to start, not counting omitted days.  If step is not  supplied,
              then it is assumed to be 1.  Note that only every stepth day is tested to see if it
              is omitted.  The optional wkday arguments are additional weekday names to omit.

              Consider this example:

                   OMIT 14 May 2009
                   SET a slide('2009-05-13', 5, "Sat", "Sun")

              In this case, a is set to 2009-05-21.  That's because we slide forward by  5  days,
              not  including  Thursday, May 14 or Saturday and Sunday, May 16 and 17.  You can go
              backwards, too, so:

                   OMIT 14 May 2009
                   SET a slide('2009-05-21', -5, "Sat", "Sun")

              takes a back to 2009-05-13.

              Now consider this example:

                      OMIT 14 May 2009
                      SET a slide('2009-05-07', 2, 7)

              This sets a to '2009-05-28' because we skip ahead two weeks, not  counting  a  week
              where the day we land on happens to be omitted.  Contrast with this:

                      OMIT 13 May 2009
                      SET a slide('2009-05-07', 2, 7)

              which  sets  a to '2009-05-21'.  Although 2009-05-13 is omitted, we don't "land" on
              it as we step forward in chunks of 7 days, so we never see that it is omitted.

       soleq(i_which [, dqi_start])
              The soleq function computes solstices and equinoxes.  The  which  parameter  ranges
              from  0  to  3,  and  specifies  which  event  we are interested in: 0 is the March
              equinox; 1 is the June solstice; 2 is the September equinox and 3 is  the  December
              solstice.

              The  optional  start  parameter can either be an integer specifying the year of the
              event we are interested in, or a DATE or DATETIME object; if the latter, then soleq
              returns  the  first  event  on  or  after  the date part of the start parameter (it
              ignores the time component if start is a DATETIME.)  If start is not supplied, then
              it defaults to today().

              The  return  value  of soleq() is a DATETIME object specifying the date and time of
              the solstice or equinox in the local time zone.  It should be accurate to within  3
              minutes or so in the worst case.

              See the included file $SysInclude/seasons.rem for examples of how to use soleq().

       stdout()
              Returns  a string representing where Remind's standard output is going.  The return
              values are one of the following: "TTY" if standard-output is a terminal, "BLOCKDEV"
              if it is a block device (very unlikely), "CHARDEV" if it is a character device (eg,
              /dev/null), "DIR" if it is a directory (very unlikely), "PIPE" if it is a  pipe  or
              FIFO,  "SYMLINK" if it is a symlink (very unlikely), "SOCKET" if it is a socket, or
              "UNKNOWN" if it could not be determined.

              The purpose of stdout() is mostly to distinguish between TTY  and  non-TTY  output;
              you may wish to change or disable colors if the output is not going to a TTY.

       strlen(s_str)
              Returns  the  length  of str.  If the length of str is too large to represent as an
              integer, emits a "Number too high" error.

       substr(s_str, i_start [,i_end])
              Returns a STRING consisting of all characters in str from start up to and including
              end.   Characters are numbered from 1.  If end is not supplied, then it defaults to
              the length of str.

       sunrise([dq_date])
              Returns a TIME indicating the time  of  sunrise  on  the  specified  date  (default
              today().)  In high latitudes, there may be no sunrise on a particular day, in which
              case sunrise() returns the INT 0 if the sun never sets, or 1440 if it never rises.

       sunset([dq_date])
              Returns a TIME indicating the  time  of  sunset  on  the  specified  date  (default
              today().)   In high latitudes, there may be no sunset on a particular day, in which
              case sunset() returns the INT 0 if the sun never rises, or 1440 if it never sets.

              The functions sunrise() and sunset() are based on  an  algorithm  in  "Almanac  for
              Computers for the year 1978" by L. E. Doggett, Nautical Almanac Office, USNO.  They
              require the latitude and longitude to  be  specified  by  setting  the  appropriate
              system  variables.  (See "System Variables".)  The sun functions should be accurate
              to within about 4 minutes for latitudes lower than 60 degrees.  The  functions  are
              available starting from version 03.00.07 of Remind.

       time(i_hr, i_min)
              Creates a TIME with the hour and minute components specified by hr and min.

       timepart(tq_datetime)
              Returns a TIME object representing the time portion of datetime.

       timezone([dq_datetime])
              Returns  a  string representing the local time zone name of the given DATETIME.  If
              no argument is supplied, Remind uses the value of current().  If a DATE rather than
              DATETIME is supplied, Remind uses a time part of 00:00.

       today()
              Returns  Remind's notion of "today."  This may be the actual system date, or a date
              supplied on the command line, or the date of the  calendar  entry  currently  being
              computed.

       trig(s_1 [,s_2, ...])
              For  each  string  argument  s_n,  trig evaluates s_n as if it were a REM or IFTRIG
              trigger specification.  If the trigger would trigger today, then the  trigger  date
              is  returned  and no further triggers are evaluated.  If none of the triggers would
              trigger today, then the zero date 1990-01-01 is returned.
              trig also has a zero-argument form; this returns  the  trigger  date  of  the  most
              recent trig function that returned a non-zero trigger date.

              trig  can  be  used to make more sophisticated versions of IFTRIG.  For example, if
              you have meetings every Monday in June and July, and you want warnings  3  days  in
              advance, you could use:

                  REM [trig("Mon Jun +3", "Mon July +3")] +3 MSG Meeting %b

              NOTE:  We  need  to  repeat  the  +3 delta outside of the trig function for advance
              warning to work properly.  This is  because  trig  returns  a  date  constant  (the
              trigger date) and the REM command does not know the details of trig's arguments.

              Note  that  because Remind does not have short-circuit logical operators, something
              like:

                  SET a trig("Mon +7") || trig("Fri +7")

              would set the value of trig() to the date of the following Thursday.   Even  though
              trig("Mon  +7")  always  returns  true,  the  logical-OR  operator  still evaluates
              trig("Fri +7") which also returns true and sets trig().

              You can work around the lack of a short-circuit  logical-OR  as  follows:  If  trig
              returns  a true value, the specific value it returns can be coerced to a DATE which
              is the trigger date.  So the following code:

                  SET a trig("Mon +4") || trig("Fri +4")
                  IF a
                      REM [a] +4 MSG [wkday($T)] %b.
                  ENDIF

              would operate as follows:

                  On Monday:    Monday today.
                  On Tuesday:   Friday in 3 days' time.
                  On Wednesday: Friday in 2 days' time.
                  On Thursday:  Monday in 4 days' time.
                  On Friday:    Monday in 3 days' time.
                  On Saturday:  Monday in 2 days' time.
                  On Sunday:    Monday tomorrow.

              Compare with the following:

                  SET a trig("Mon +4") || trig("Fri +4")
                  IF a
                      REM [trig()] +4 MSG [wkday($T)] %b.
                  ENDIF

              which yields:

                  On Monday:    Friday in 4 days' time.
                  On Tuesday:   Friday in 3 days' time.
                  On Wednesday: Friday in 2 days' time.
                  On Thursday:  Friday tomorrow.
                  On Friday:    Friday today.
                  On Saturday:  Monday in 2 days' time.
                  On Sunday:    Monday tomorrow.

              That is because trig() returns the trigger date of  the  last  trig  function  that
              returns true, whereas the value of a is the trigger date of the first trig function
              that returns true.

              Important Note:  Because trig() always returns an absolute date, it will  not  work
              properly with a SATISFY clause.  Consider this reminder:

                  REM [trig("Mar", "Apr")] SATISFY [$Td == 15] MSG 15 Mar or April

              If we run Remind on 5 March 2022, we might expect the trigger date to be calculated
              as 15 March 2022... but that's not what happens.  Instead,  the  trig  function  is
              evaluated  first, and it returns 2022-03-05.  So as far as Remind is concerned, the
              REM statement becomes:

                  REM 2022-03-05 SATISFY [$Td == 15] MSG 15 Mar or April

              and the SATISFY expression is never true.  So: Do not mix trig() and SATISFY.

       trigdate()
              Returns the calculated trigger date of the last REM or IFTRIG command.  If used  in
              the body of a REM command, returns that command's trigger date.  If the most recent
              REM command did not yield a computable trigger date, returns the integer 0.

       trigdatetime()
              Similar to trigdate(), but returns a DATETIME if the most  recent  triggerable  REM
              command  had  an  AT  clause.   If  there  was no AT clause, returns a DATE.  If no
              trigger could be computed, returns the integer 0.  See "MULTI-DAY EVENTS" for  more
              information.

       trigeventstart()
              Returns  a  DATETIME  representing  the  start  of  the most recent triggerable REM
              command that had an AT clause.  For events without a DURATION or that do  not  span
              multiple days, returns the same as trigdatetime().  If the REM command did not have
              an AT clause, returns the integer -1  (and  differs  from  trigdatetime()  in  this
              respect.)  See "MULTI-DAY EVENTS" for more information.

       trigeventduration()
              Returns a TIME representing the duration of the most recent triggerable REM command
              that had an AT and a DURATION clause.  If the event does not  span  multiple  days,
              returns  the  same  thing  as  trigduration().   If the REM command lacked an AT or
              DURATION clause, returns -1.  See "MULTI-DAY EVENTS" for more information.

       trigback()
              Returns the "back" amount of the last REM or IFTRIG command.   Returns  a  positive
              integer  N  if  the "back" is of the form -N, or a negative integer if it is of the
              form --N.  If there is no "back", then returns 0.

       trigdelta()
              Returns the "delta" amount of the last REM or IFTRIG command.  Returns  a  positive
              integer  N  if the "delta" is of the form +N, or a negative integer if it is of the
              form ++N.  If there is no "delta", then returns 0.

       trigtimedelta()
              Similar to trigdelta(), but returns the delta used in the  AT  clause  of  a  timed
              reminder.

       trigrep()
              Returns  the "repeat" amount of the last REM or IFTRIG command.  Returns a positive
              integer N if the "repeat" is of the form *N.  If there is no "repeat", then returns
              0.

       trigtimerep()
              Similar  to  trigrep(),  but  returns  the  repeat used in the AT clause of a timed
              reminder.

       trigduration()
              Returns (as a TIME type) the DURATION parameter of a timed reminder.  If  there  is
              no  DURATION  parameter,  returns  the integer -1.  See "MULTI-DAY EVENTS" for more
              information.

       trigpriority()
              Returns the PRIORITY of the last REM or IFTRIG command.

       triguntil()
              Returns (as a DATE type) the UNTIL parameter of the last REM or IFTRIG command.  If
              there  was  no  UNTIL  parameter,  returns  the  integer -1.  If there is a THROUGH
              parameter, that will be returned  by  triguntil()  since  "THROUGH  yyyy-mm-dd"  is
              simply syntactic sugar for "*1 UNTIL yyyy-mm-dd".

       trigscanfrom()
              Returns  (as a DATE type) the SCANFROM parameter of the last REM or IFTRIG command.
              If there was no SCANFROM parameter, returns the integer -1.   Note  that  FROM  and
              SCANFROM interact; a reminder that has a "FROM yyyy-mm-dd" parameter will act as if
              it has a SCANFROM parameter whose value is the maximum of "yyyy-mm-dd" and today.

       trigfrom()
              Returns (as a DATE type) the FROM parameter of the last REM or IFTRIG command.   If
              there was no FROM parameter, returns the integer -1.

       trigger(d_date [,t_time [,i_utcflag]]) or trigger(q_datetime [,i_utcflag])
              Returns  a  string suitable for use in a REM command or a SCANFROM or UNTIL clause,
              allowing you to calculate trigger dates in advance.  Note that in earlier  versions
              of  Remind,  trigger  was required to convert a date into something the REM command
              could consume.  However, in this version of Remind, you can  omit  it.   Note  that
              trigger()  always  returns  its result in English, even for non-English versions of
              Remind.  Normally, the date and time are the  local  date  and  time;  however,  if
              utcflag  is  non-zero,  the  date  and  time  are interpreted as UTC times, and are
              converted to local time.  Examples:

                   trigger('1993/04/01')

              returns "1 April 1993",

                   trigger('1994/08/09', 12:33)

              returns "9 August 1994 AT 12:33", as does:

                   trigger('1994/08/09@12:33').

              Finally:

                   trigger('1994/12/01', 03:00, 1)

              returns "30 November 1994 AT 22:00" for EST, which is  5  hours  behind  UTC.   The
              value for your time zone may differ.

       trigtags()
              Returns  a  comma-separated  list  of  the TAGs associated with the most recent REM
              command that was triggered.  Returns the empty string if there were  no  TAGs.   If
              there are multiple tags, they are each separated by a single comma, not a comma and
              a space.

       trigtime()
              Returns the time of the last REM command with an AT clause.  If the  last  REM  did
              not  have  an  AT clause, returns the integer 0.  If a REM command has an AT clause
              with a DURATION, then you can compute the end time as trigtime() + trigduration().

       trigvalid()
              Returns 1 if the value returned by trigdate() is valid  for  the  most  recent  REM
              command,  or  0 otherwise.  Sometimes REM commands cannot calculate a trigger date.
              For example, the following REM command can never be triggered:

                 REM Mon OMIT Mon SKIP MSG Impossible!

       typeof(x_arg)
              Returns "STRING", "INT", "DATE", "TIME" or "DATETIME", depending  on  the  type  of
              arg.

       tzconvert(q_datetime, s_srczone [,s_dstzone])
              Converts  datetime  from  the  time zone named by srczone to the time zone named by
              dstzone.  If dstzone is omitted, the default system time zone is used.  The  return
              value  is a DATETIME.  Time zone names are system-dependent; consult your operating
              system for legal values.  Here is an example:

           tzconvert('2007-07-08@01:14', "Canada/Eastern", "Canada/Pacific")

                 returns

           2007-07-07@22:14

       upper(s_string)
              Returns a STRING with all lower-case characters in string converted to upper-case.

       utctolocal(q_datetime)
              Given a DATETIME object interpreted in UTC, return a DATETIME object that expresses
              the same time in the local time zone.

       value(s_varname [,x_default])
              Returns  the  value of the specified variable.  For example, value("X"+"Y") returns
              the value of variable XY, if it is  defined.   If  XY  is  not  defined,  an  error
              results.

              However,  if  you  supply  a  second argument, it is returned if the varname is not
              defined.  The expression value("XY", 0) will return 0 if XY is not defined, and the
              value of XY if it is defined.

       version()
              Returns  a  string specifying the version of Remind.  For version 04.03.01, returns
              "04.03.01".  It is guaranteed that as new versions  of  Remind  are  released,  the
              value  returned  by  version()  will  strictly increase, according to the rules for
              string ordering.

       weekno([dq_date, [i_wkstart, [i_daystart]]])
              Returns the week number of the year.  If no arguments are supplied, returns the ISO
              8601  week  number for today().  If one argument date is supplied, then returns the
              ISO 8601 week number for that date.  If two arguments are  supplied,  then  wkstart
              must  range  from  0  to  6, and represents the first day of the week (with 0 being
              Sunday and 6 being Saturday.).  If wkstart is not supplied, then it defaults to  1.
              If  the  third argument daystart is supplied, then it specifies when Week 1 starts.
              If daystart is less than or equal to 7, then Week 1 starts on the first wkstart  on
              or  after  January  daystart.   Otherwise, Week 1 starts on the first wkstart on or
              after December daystart.  If omitted, daystart defaults to 29  (following  the  ISO
              8601 definition.)

       wkday(dqi_arg)
              If  arg is a DATE or DATETIME, returns a string representing the day of the week of
              the date.  If arg is an  INT  from  0  to  6,  returns  the  corresponding  weekday
              ("Sunday" to "Saturday").

       wkdaynum(dq_date)
              Returns  a  number  from 0 to 6 representing the day-of-week of the specified date.
              (0 represents Sunday, and 6 represents Saturday.)

       year(dq_date)
              Returns a INT that is the year component of date.

MULTI-DAY EVENTS

       If you specify a start time with AT and a duration with DURATION, you  can  create  events
       that span multiple days.  Consider these two REM statements:

           REM 1991-02-13 AT 16:00 DURATION 72:00 MSG 72-hour event
           REM 1991-02-13 THROUGH 1991-02-16 AT 16:00 MSG Four events

       The  first  statement  creates a single event that starts on 13 February 1991 at 16:00 and
       runs through 16 February 1991 at 16:00

       The second statements creates four separate events that start at 16:00 on 13, 14,  15  and
       16 February 1991 and have indefinite duration.

       Remind handles multi-day events specially.  These are the rules:

       On  the  first  day of a multi-day event, trigdatetime() will return the starting date and
       time of the event, and trigduration() will return the original DURATION.

       On each subsequent day of a multi-day event, trigdatetime() will return  midnight  on  the
       day  in  question,  and  trigduration() will return the remaining duration.  Consider this
       example:

           #!/bin/sh
           remind - 12 feb 1991 '*6' <<'EOF'
           BANNER %
           REM 1991-02-13 AT 16:00 DURATION 72:00 SATISFY 1
           set a trigdatetime()
           set b trigduration()
           set c trigeventstart()
           set d trigeventduration()
           MSG now=[today()] dt=[a] dur=[b] estart=[c] edur=[d]%
           EOF

       The output is:

       now=1991-02-12 dt=1991-02-13@16:00 dur=72:00 estart=1991-02-13@16:00 edur=72:00
       now=1991-02-13 dt=1991-02-13@16:00 dur=72:00 estart=1991-02-13@16:00 edur=72:00
       now=1991-02-14 dt=1991-02-14@00:00 dur=64:00 estart=1991-02-13@16:00 edur=72:00
       now=1991-02-15 dt=1991-02-15@00:00 dur=40:00 estart=1991-02-13@16:00 edur=72:00
       now=1991-02-16 dt=1991-02-16@00:00 dur=16:00 estart=1991-02-13@16:00 edur=72:00
       now=1991-02-17 dt=1991-02-13@16:00 dur=72:00 estart=-1 edur=-1

       As you see, the trigdatetime() and trigduration() functions  return  the  start  time  and
       duration  of  the  remaining  portion  of  a  multi-day  event, whereas trigeventstart and
       trigeventduration always return the original start and duration of  the  multi-day  event.
       Note  also  that  the  return  value  for expired reminders is not reliable; the fact that
       trigeventstart and trigeventduration return -1 in that case is an implementation artifact.

       SELF-OVERLAPPING EVENTS

       A multi-day event has the possibility of "overlapping itself".  When this happens,  Remind
       prefers  the  later  event (only one copy of an event is ever triggered for a given date.)
       Consider this example:

          #!/bin/sh
          remind - '*5' 10 Feb 1991 <<'EOF'

          BANNER %
          REM MON at 0:00 DURATION 192:0 MSG [today()] [trigeventstart()] [trigduration()]%

          EOF

       The output is:

          1991-02-10 1991-02-04@00:00 48:00
          1991-02-11 1991-02-11@00:00 192:00
          1991-02-12 1991-02-11@00:00 168:00
          1991-02-13 1991-02-11@00:00 144:00
          1991-02-14 1991-02-11@00:00 120:00

       Although the event from 1991-02-04 still has  24  hours  left  on  1991-02-11,  the  fresh
       occurrence on 1991-02-11 takes precedences and is the one that is triggered.

       I do not recommend constructing self-overlapping multi-day events.

EXPRESSION PASTING

       An extremely powerful feature of Remind is its macro capability, or "expression pasting."

       In  almost  any  situation where Remind is not expecting an expression, you can "paste" an
       expression in.  To do this, surround the expression with square brackets.  For example:

            REM [mydate] MSG foo

       This evaluates the expression "mydate", where "mydate"  is  presumably  some  pre-computed
       variable, and then "pastes" the result into the command-line for the parser to process.

       A  formal  description  of  this  is:  When Remind encounters a "pasted-in" expression, it
       evaluates the expression, and coerces the result to a STRING.   It  then  substitutes  the
       string  for  the  pasted-in  expression,  and  continues  parsing.   Note,  however,  that
       expressions are evaluated only once, not recursively.  Thus, writing:

            ["[a+b]"]

       causes Remind to read the token "[a+b]".  It  does  not  interpret  this  as  a  pasted-in
       expression.  In fact, the only way to get a literal left-bracket into a reminder is to use
       ["["].

       You can use expression pasting almost anywhere.  However, there are a few exceptions:

       o      If Remind is expecting an expression, as in the SET command, or the IF command, you
              should not include square brackets.  For example, use:

                 SET a 4+5
       and not:
                 SET a [4+5]

       o      You  cannot use expression pasting for the first token on a line.  For example, the
              following will not work:

                 ["SET"] a 1

              This restriction is because Remind must be  able  to  unambiguously  determine  the
              first token of a line for the flow-control commands (to be discussed later.)

              In  fact,  if Remind cannot determine the first token on a line, it assumes that it
              is a REM command.  If expression-pasting is  used,  Remind  assumes  it  is  a  REM
              command.  Thus, the following three commands are equivalent:

                        REM 12 Nov 1993 AT 13:05 MSG BOO!
                        12 Nov 1993 AT 13:05 MSG BOO!
                        [12] ["Nov " + 1993] AT [12:05+60] MSG BOO!

       o      You  cannot  use expression-pasting to determine the type (MSG, CAL, etc.) of a REM
              command.  You can paste expressions before and after the MSG,  etc.  keywords,  but
              cannot do something like this:

                      REM ["12 Nov 1993 AT 13:05 " + "MSG" + " BOO!"]

              However, as an escape hatch, the sequence SPECIAL type means the same thing as just
              type where type is one of MSG, MSF, RUN, CAL, PS and  PSFILE.   This  lets  you  do
              something like this:

                      SET type "MSG"
                      REM 12 Nov 2024 SPECIAL [type] Hello

              You can use this to control the types of your reminders based on variables you set,
              how Remind is invoked, etc.

       COMMON PITFALLS WITH EXPRESSION PASTING

       Remember that extra spaces are not inserted when an expression is pasted.  Thus, something
       like:

            REM[expr]MSG[expr]

       will probably fail.

       If  you  use  an  expression  to  calculate  a  delta or back, ensure that the result is a
       positive number.  Something like:

            REM +[mydelta] Nov 12 1993 MSG foo

       will fail if mydelta happens to be negative.

FLOW CONTROL COMMANDS

       Remind has commands that control the  flow  of  a  reminder  script.   Normally,  reminder
       scripts are processed sequentially.  However, IF and related commands allow you to process
       files conditionally, and skip sections that you don't want interpreted.

       THE IF COMMAND

       The IF command has the following form:

            IF expr
                 t-command
                 t-command...
            ELSE
                 f-command
                 f-command...
            ENDIF

       Note that the commands are shown indented for clarity.  Also,  the  ELSE  portion  can  be
       omitted.  IF commands can be nested up to a small limit, probably around 8 or 16 levels of
       nesting, depending on your system.

       If the expr evaluates to a non-zero INT, a DATE that is not 1990-01-01, a TIME that is not
       00:00,  a DATETIME that is not 1990-01-01@00:00, or a non-null STRING, then the IF portion
       is considered true, and the t-commands are executed.  If expr evaluates to zero  or  null,
       then the f-commands (if the ELSE portion is present) are executed.

       Examples:

            IF defined("want_hols")
                 INCLUDE /usr/share/remind/holidays
            ENDIF

            IF today() > '1992/2/10'
                 set missed_ap "You missed it!"
            ELSE
                 set missed_ap "Still have time..."
            ENDIF

       THE IFTRIG COMMAND

       The  IFTRIG  command is similar to an IF command, except that it computes a trigger (as in
       the REM command), and evaluates to true if a  corresponding  REM  command  would  trigger.
       Examples:

            IFTRIG 1 Nov
                 ; Executed on 1 Nov
            ELSE
                 ; Executed except on 1 Nov
            ENDIF

            IFTRIG 1 -1 OMIT Sat Sun +4
                 ; Executed on last working day of month,
                 ; and the 4 working days preceding it
            ELSE
                 ; Executed except on above days
            ENDIF

       Note  that  the  IFTRIG  command  computes a trigger date, which can be retrieved with the
       trigdate() function.  You can use all of the normal trigger  components,  such  as  UNTIL,
       delta,  etc. in the IFTRIG command.  However, you cannot use a type specifier such as CAL,
       MSG or SATISFY; attempting to do so yields a parse error.

USER-DEFINED FUNCTIONS

       In addition to the built-in functions, Remind allows you to  define  your  own  functions.
       The FSET command does this for you:

       FSET fname(args) expr

       Fname  is the name of the function, and follows the convention for naming variables.  Args
       is a comma-separated list of arguments, and expr is an expression.  Args can be empty,  in
       which case you define a function taking no parameters.  Here are some examples:

            FSET double(x) 2*x
            FSET yeardiff(date1, date2) year(date1) - year(date2)
            FSET since(x) ord($Ty - x)

       The last function is useful in birthday reminders.  For example:

            REM 1 Nov +12 MSG Dean's [since(1984)] birthday is %b.

       Dean was born in 1984.  The above example, on 1 November 1992, would print:

            Dean's 8th birthday is today.

       Similarly, the function is useful in anniversary reminders.  For example:

               REM 4 June MSG [since(1989)] anniversary of the Tienanmen Square massacre

       Notes:

       o      If  you  access a variable in expr that is not in the list of arguments, the global
              value (if any) is used.

       o      Function and parameter names are significant to 64 characters.

       o      The value() function always accesses the global value of a variable, even if it has
              the same name as an argument.  For example:

                        fset func(x) value("x")
                        set x 1
                        set y func(5)

              The above sequence sets y to 1, which is the global value of x.

       o      User-defined  functions  may  call  other  functions,  including other user-defined
              functions.  However, recursive calls are not allowed.

       o      User-defined functions are not syntax-checked when they are defined; parsing occurs
              only when they are called.

       o      If  a user-defined function has the same name as a built-in function, it is ignored
              and the built-in function is used.  To prevent conflicts with  future  versions  of
              Remind  (which  may define more built-in functions), you may wish to name all user-
              defined functions beginning with an underscore.

       To delete a user-defined function, use FUNSET.  This takes a space-separated list of user-
       defined functions to delete.  For example, after the command:

               FUNSET myfunc1 otherfunc thirdfunc

       it is guaranteed that no user-defined functions named myfunc1, otherfunc or thirdfunc will
       exist.  Remind does not issue an error if you try to  FUNSET  a  nonexistent  user-defined
       function; it simply does nothing in that case.

PRECISE SCHEDULING

       The  WARN  keyword  allows  precise control over advance warning in a more flexible manner
       than the delta mechanism.  It should be followed by the name of a  user-defined  function,
       warn_function.

       If  a  warn_function  is  supplied,  then  it  must take one argument of type INT.  Remind
       ignores any delta, and instead calls warn_function successively with the arguments  1,  2,
       3, ...

       Warn_function's return value n is interpreted as follows:

       o      If  n is positive, then the reminder is triggered exactly n days before its trigger
              date.

       o      If n is negative, then it is triggered n days before its trigger date, not counting
              OMITted days.

       As an example, suppose you wish to be warned of American Independence Day 5, 3, and 1 days
       in advance.  You could use this:

            FSET _wfun(x) choose(x, 5, 3, 1, 0)
            REM 4 July WARN _wfun MSG American Independence Day is %b.

       NOTES

       1      If an error occurs during  the  evaluation  of  warn_function,  then  Remind  stops
              calling it and simply issues the reminder on its trigger date.

       2      If  the absolute-values of the return values of warn_function are not monotonically
              decreasing, Remind stops calling it and issues the reminder on its trigger date.

       3      Warn_function should (as a matter of good style) return 0 as the final value in its
              sequence  of  return  values.   However, a reminder will always be triggered on its
              trigger date, regardless of what warn_function does.

       Similarly to WARN, the SCHED keyword allows precise control over the scheduling  of  timed
       reminders.  It should be followed by the name of a user-defined function, sched_function.

       If  a scheduling function is supplied, then it must take one argument of type INT.  Rather
       than using the AT time, time delta, and time repeat, Remind calls the scheduling  function
       to  determine  when  to  trigger the reminder.  The first time the reminder is queued, the
       scheduling function is called with an argument of 1.  Each time the reminder is triggered,
       it  is  re-scheduled by calling the scheduling function again.  On each call, the argument
       is incremented by one.

       The return value of the scheduling function must be an INT or a TIME.  If the return value
       is  a  TIME,  then the reminder is re-queued to trigger at that time.  If it is a positive
       integer n, then the reminder is re-queued to trigger at the previous trigger time  plus  n
       minutes.   Finally, if it is a negative integer or zero, then the reminder is re-queued to
       trigger n minutes before the AT time.  Note that there must be an AT clause for the  SCHED
       clause to do anything.

       Here's an example:

            FSET _sfun(x) choose(x, -60, 30, 15, 10, 3, 1, 1, 1, 1, 0)
            REM AT 13:00 SCHED _sfun MSG foo

       The  reminder would first be triggered at 13:00-60 minutes, or at 12:00.  It would next be
       triggered 30 minutes later, at 12:30.  Then, it would be triggered at 12:45, 12:55, 12:58,
       12:59, 13:00, 13:01 and 13:02.

       NOTES

       1      If  an  error  occurs  during  the evaluation of sched_func, then Remind reverts to
              using the AT time and the delta and  repeat  values,  and  never  calls  sched_func
              again.

       2      If  processing sched_func yields a time earlier than the current system time, it is
              repeatedly called with increasing argument until it yields a value greater than  or
              equal  to  the  current time.  However, if the sequence of values calculated during
              the repetition is not strictly increasing,  then  Remind  reverts  to  the  default
              behaviour and never calls sched_func again.

       3      It  is quite possible using sched_func to keep triggering a reminder even after the
              AT-time.  However, it is not possible to reschedule a reminder past midnight  -  no
              crossing  of date boundaries is allowed.  Also, it is quite possible to not trigger
              a reminder on the AT time when you use a scheduling  function.   However,  if  your
              scheduling  function  is terminated (for reasons 1 and 2) before the AT time of the
              reminder, it will be triggered at the AT  time,  because  normal  processing  takes
              over.

       4      Your  scheduling functions should (as a matter of good style) return 0 when no more
              scheduling is required.  See the example.

       5      All scheduling functions are evaluated after the entire Remind script has been read
              in.   So  whatever  function definitions are in effect at the end of the script are
              used.

THE SATISFY CLAUSE

       The form of REM that uses SATISFY is as follows:

       REM trigger SATISFY expr

       The way this works is as follows:  Remind first calculates a trigger date, in  the  normal
       fashion.   Next,  it  sets  trigdate()  to the calculated trigger date.  It then evaluates
       expr.  If the result is not the null string or zero, processing ends.   Otherwise,  Remind
       computes  the  next  trigger date, and re-tests expr.  This iteration continues until expr
       evaluates to non-zero or non-null, or until the iteration  limit  specified  with  the  -x
       command-line option is reached.

       If  expr  is  not  satisfied,  then  trigvalid()  is set to 0 and the error message "Can't
       compute trigger" is issued.  Otherwise, trigvalid() is set to 1.

       This is really useful only if expr involves a call to the trigdate() or related functions;
       otherwise, expr will not change as Remind iterates.

       An  example  of  the usefulness of SATISFY:  Suppose you wish to be warned of every Friday
       the 13th.  Your first attempt may be:

            # WRONG!
            REM Fri 13 +2 MSG Friday the 13th is %b.

       But this won't work.  This reminder triggers on the first Friday on or after the  13th  of
       each month.  The way to do it is with a more complicated sequence:

            REM 13 SATISFY wkdaynum(trigdate()) == 5
            IF trigvalid()
                 REM [trigdate()] +2 MSG \
                 Friday the 13th is %b.
            ENDIF

       You can write the REM statement a little more concisely:

            REM 13 SATISFY $Tw == 5

       Let's see how this works.  The SATISFY clause iterates through all the 13ths of successive
       months, until a trigger date is found whose day-of-week is Friday (== 5).  If a valid date
       was found, we use the calculated trigger date to set up the next reminder.

       We could also have written:

            REM Fri SATISFY day(trigdate()) == 13

       but  this would result in more iterations, since "Fridays" occur more often than "13ths of
       the month."

       Here is another example: Suppose you want to be reminded  of  something  on  the  15th  of
       January,  April,  July, and October.  You could make four separate reminders, or you could
       use:

               REM 15 SATISFY [isany($Tm, 1, 4, 7, 10)] MSG 15th Reminder!

       This technique of using one REM command to calculate a trigger date to be used by  another
       command  is  quite powerful.  For example, suppose you wanted to OMIT Labour day, which is
       the first Monday in September.  You could use:

            # Note: SATISFY 1 is an idiom for "do nothing"
            REM Mon 1 Sept SATISFY 1
            OMIT [trigdate()]

       CAVEAT: This only omits the next Labour Day, not all Labour  Days  in  the  future.   This
       could cause strange results, as the OMIT context can change depending on the current date.
       For example, if you use the following command after the above commands:

            REM Mon AFTER msg hello

       the result will not be as you expect.  Consider producing a calendar for September,  1992.
       Labour  Day  was  on  Monday,  7  September,  1992.   However,  when Remind gets around to
       calculating the trigger for Tuesday, 8 September, 1992,  the  OMIT  command  will  now  be
       omitting Labour Day for 1993, and the "Mon AFTER" command will not be triggered.  (But see
       the description of SCANFROM in the section "DETAILS ABOUT TRIGGER COMPUTATION.")

       It is probably best to stay away from computing OMIT trigger dates unless you  keep  these
       pitfalls in mind.

       For  versions of Remind starting from 03.00.07, you can include a MSG, RUN, etc. clause in
       a SATISFY clause as follows:

            REM trigger_stuff SATISFY [expr] MSG body

       Note that for this case only, the expr after SATISFY must be enclosed in square  brackets.
       It  must  come  after  all the other components of the trigger, and immediately before the
       MSG, RUN, etc. keyword.  If expr cannot be satisfied, then the reminder is not triggered.

       Thus, the "Friday the 13th" example can be expressed more compactly as:

            REM 13 +2 SATISFY [$Tw == 5] MSG Friday the 13th is %b.

       And you can trigger a reminder on Mondays, Wednesdays  and  Thursdays  occurring  on  odd-
       numbered days of the month with the following:

            REM Mon Wed Thu SATISFY [$Td %2 ] MSG Here it is!!!

       Note  that  SATISFY  and  OMITFUNC  can often be used to solve the same problem, though in
       different ways.  Sometimes a SATISFY is cleaner and sometimes an OMITFUNC; experiment  and
       use whichever seems clearer.

POSSIBLY-UNCOMPUTABLE TRIGGERS

       Occasionally,  you may wish to suppress the "Can't compute trigger" warnings for reminders
       for which a trigger date cannot be computed.   For  example,  the  following  reminder  is
       triggered on a Monday that is not a holiday if the following Tuesday is a holiday:

               REM Mon SKIP SATISFY [isomitted($T+1)] MSG Work between holidays

       However,  if  there  are  no Mondays after today's date that satisfy the condition, Remind
       will print  the  "Can't  compute  trigger"  error.   To  suppress  this,  use  the  MAYBE-
       UNCOMPUTABLE keyword:

               REM MAYBE-UNCOMPUTABLE Mon SKIP SATISFY [isomitted($T+1)] MSG Work between holidays

       It's almost never appropriate to use MAYBE-UNCOMPUTABLE, but it is provided for those rare
       occasions when it makes sense.   If  you  use  MAYBE-UNCOMPUTABLE  inside  the  evaltrig()
       function, then untriggerable triggers return -1.  For example:

               SET a evaltrig("MAYBE-UNCOMPUTABLE Mon SKIP OMIT Mon")

       will set a to -1.

DEBUGGING REMINDER SCRIPTS

       Although  the  command-line  -d option is useful for debugging, it is often overkill.  For
       example, if you turn on the -dx option for a reminder file with many complex  expressions,
       you'll get a huge amount of output.  The DEBUG command allows you to control the debugging
       flags under program control.  The format is:

       DEBUG [+flagson] [-flagsoff]

       Flagson and flagsoff consist of strings of the characters "extvlf" that correspond to  the
       debugging  options discussed in the command-line options section.  If preceded with a "+",
       the corresponding group of debugging options is switched on.  Otherwise, they are switched
       off.  For example, you could use this sequence to debug a complicated expression:

            DEBUG +x
            set a very_complex_expression(many_args)
            DEBUG -x

       THE DUMPVARS COMMAND

       The command DUMPVARS displays the values of variables in memory.  Its format is:

       DUMPVARS [var...]

       If  you  supply  a space-separated list of variable names, the corresponding variables are
       displayed.  If you do not supply a list of variables, then all  variables  in  memory  are
       displayed.   To dump a system variable, put its name in the list of variables to dump.  If
       you put a lone dollar sign in the list of variables to dump,  then  all  system  variables
       will be dumped.

       THE ERRMSG COMMAND

       The ERRMSG command has the following format:

       ERRMSG body

       The  body  is  passed  through  the  substitution filter (with an implicit trigger date of
       today()) and printed to the error output stream.  Example:

            IF !defined("critical_var")
                 ERRMSG You must supply a value for "critical_var"
                 EXIT
            ENDIF

       THE EXIT COMMAND

       The above example also shows the use of the EXIT command.  This  causes  an  unconditional
       exit  from  script  processing.   Any queued timed reminders are discarded.  If you are in
       calendar mode (described next), then the calendar processing is aborted.

       If you supply an INT-type expression after the EXIT command, it is returned to the calling
       program as the exit status.  Otherwise, an exit status of 99 is returned.

       THE FLUSH COMMAND

       This  command  simply consists of the word FLUSH on a line by itself.  The command flushes
       the standard output and standard error streams used  by  Remind.   This  is  not  terribly
       useful  to  most  people,  but  may be useful if you run Remind as a subprocess of another
       program, and want to use pipes for communication.

CALENDAR MODE

       If you supply the -c, -s or -p command-line option, then Remind runs in  "calendar  mode."
       In  this  mode,  Remind interprets the script repeatedly, performing one iteration through
       the whole file for each day in the calendar.  Reminders that trigger are saved in internal
       buffers, and then inserted into the calendar in the appropriate places.

       If  you  also  supply  the  -a option, then Remind will not include timed reminders in the
       calendar.

       The -p option is used in conjunction with the Rem2PS program  to  produce  a  calendar  in
       PostScript  format.   For  example,  the  following  command  will send PostScript code to
       standard output:

            remind -p .reminders | rem2ps

       You can print a PostScript calendar by piping this to the lpr command.

       If you have a reminder script called ".reminders", and you execute this command:

            remind -c .reminders jan 1993

       then Remind executes the script 31 times, once for each day  in  January.   Each  time  it
       executes the script, it increments the value of today().  Any reminders whose trigger date
       matches today() are entered into the calendar.

       MSG and CAL-type reminders, by default, have their entire body inserted into the calendar.
       RUN-type reminders are not normally inserted into the calendar.  However, if you enclose a
       portion of the body in the %"...%" sequence, only that portion is inserted.  For  example,
       consider the following:

            REM 6 Jan MSG %"Dianne's birthday%" is %b

       In  the  normal  mode,  Remind  would  print  "Dianne's  birthday  is today" on 6 January.
       However, in the calendar mode, only the text "Dianne's birthday" is inserted into the  box
       for 6 January.

       If  you  explicitly use the %"...%" sequence in a RUN-type reminder, then the text between
       the delimiters is inserted into the calendar.  If you use the sequence %"%" in  a  MSG  or
       CAL-type reminder, then no calendar entry is produced for that reminder.

       PRESERVING VARIABLES

       Because  Remind  iterates through the script for each day in the calendar, slow operations
       may severely reduce the speed of producing a calendar.

       For example, suppose you set the variables "me" and "hostname" as follows:

            SET me shell("whoami")
            SET hostname shell("hostname")

       Normally, Remind clears all variables between iterations in calendar  mode.   However,  if
       certain  variables  are  slow  to compute, and will not change between iterations, you can
       "preserve" their values with the PRESERVE command.  Also, since function  definitions  are
       preserved  between  calendar  iterations,  there  is  no  need  to  redefine  them on each
       iteration.  Thus, you could use the following sequence:

            IF ! defined("initialized")
                 set initialized 1
                 set me shell("whoami")
                 set hostname shell("hostname")
                 fset func(x) complex_expr
                 preserve initialized me hostname
            ENDIF

       The operation is as follows:  On the first iteration through the script, "initialized"  is
       not  defined.  Thus, the commands between IF and ENDIF are executed.  The PRESERVE command
       ensures that the values of initialized, me  and  hostname  are  preserved  for  subsequent
       iterations.   On  the  next  iteration,  the  commands  are skipped, since initialized has
       remained defined.  Thus, time-consuming operations that do not  depend  on  the  value  of
       today() are done only once.

       Most  system  variables  (those  whose  names  start with '$') are automatically preserved
       between calendar iterations.

       Note that for efficiency, Remind caches the reminder script (and any  INCLUDEd  files)  in
       memory when producing a calendar.

       Timed reminders are sorted and placed into the calendar in time order.  These are followed
       by non-timed reminders.  Remind automatically places the time of timed  reminders  in  the
       calendar  according  to the -b command-line option.  Reminders in calendar mode are sorted
       as if the -g option had been used; you can change the  sort  order  in  calendar  mode  by
       explicitly using the -g option to specify a different order from the default.

       REPEATED EXECUTION

       If  you  supply  a  repeat parameter on the command line, and do not use the -c, -p, or -s
       options, Remind operates in a similar manner to calendar mode.  It repeatedly executes the
       reminder  script,  incrementing  today()  with  each  iteration.   The  same  rules  about
       preserving variables and function definitions  apply.   Note  that  using  repeat  on  the
       command line also enables the -q option and disables any -z option.  As an example, if you
       want to see how Remind will behave for the next week, you can type:

            remind .reminders '*7'

       If you want to print the dates of the next 1000 days, use:

            (echo 'banner %'; echo 'msg [today()]%') | remind - '*1000'

INITIALIZING VARIABLES ON THE COMMAND LINE

       The -i option is used to initialize variables on the Remind command line.  The  format  is
       -ivar=expr,  where  expr is any valid expression.  Note that you may have to use quotes or
       escapes to prevent the shell from interpreting special characters in expr.  You  can  have
       as  many  -i  options  as  you  want on the command line, and they are processed in order.
       Thus, if a variable is defined in one -i option, it can be referred to  by  subsequent  -i
       options.

       Note  that  if  you  supply a date on the command line, it is not parsed until all options
       have been processed.  Thus, if you use today() in any  of  the  -i  expressions,  it  will
       return the same value as realtoday() and not the date supplied on the command line.

       Any variables defined on the command line are preserved as with the PRESERVE command.

       You  should  not  have  any  spaces  between  the -i option and the equal sign; otherwise,
       strange variable names are created that can only be accessed with the value() or defined()
       functions.

       You can also define a function on the command line by using:

       -ifunc(args)=definition

       Be sure to protect special characters from shell interpretation.

MORE ABOUT POSTSCRIPT

       The  PS and PSFILE reminders pass PostScript code directly to the printer.  They differ in
       that the PS-type reminder passes  its  body  directly  to  the  PostScript  output  (after
       processing  by the substitution filter) while the PSFILE-type's body should simply consist
       of a filename.  The Rem2PS program will open the file named in the  PSFILE-type  reminder,
       and include its contents in the PostScript output.

       The  PostScript-type  reminders for a particular day are included in the PostScript output
       in sorted order of priority.  Note that the order  of  PostScript  commands  has  a  major
       impact  on  the  appearance  of  the  calendars.   For example, PostScript code to shade a
       calendar box will obliterate code to draw a moon symbol if the moon symbol code is  placed
       in  the  calendar  first.   For  this  reason,  you  should  not provide PS or PSFILE-type
       reminders with priorities; instead, you should ensure that they  appear  in  the  reminder
       script  in  the  correct  order.   PostScript  code  should  draw objects working from the
       background to the foreground, so that foreground objects properly overlay background ones.
       If  you  prioritize  these  reminders  and  run the script using descending sort order for
       priorities, the PostScript output will not work.

       All of the PostScript code for a particular date  is  enclosed  in  a  save-restore  pair.
       However, if several PostScript-type reminders are triggered for a single day, each section
       of PostScript is not enclosed in a  save-restore  pair  -  instead,  the  entire  body  of
       included PostScript is enclosed.

       PostScript-type  reminders  are  executed  by  the  PostScript  printer before any regular
       calendar entries.   Thus,  regular  calendar  entries  will  overlay  the  PostScript-type
       reminders, allowing you to create shaded or graphical backgrounds for particular days.

       Before  executing  your PostScript code, the origin of the PostScript coordinate system is
       positioned to the bottom left-hand corner  of  the  "box"  in  the  calendar  representing
       today().   This  location  is  exactly in the middle of the intersection of the bottom and
       left black lines delineating the box - you may have to account for the thickness of  these
       lines when calculating positions.

       Several  PostScript  variables  are  available  to  the  PostScript  code you supply.  All
       distance and size variables are in PostScript units (1/72 inch.)  The variables are:

       LineWidth
              The width of the black grid lines making up the calendar.

       Border The border between the center of the  grid  lines  and  the  space  used  to  print
              calendar entries.  This border is normally blank space.

       BoxWidth and BoxHeight
              The  width  and  height  of  the  calendar  box, from center-to-center of the black
              gridlines.

       InBoxHeight
              The height from the center of the bottom black gridline to the top of  the  regular
              calendar  entry  area.   The  space from here to the top of the box is used only to
              draw the day number.

       /DayFont, /EntryFont, /SmallFont, /TitleFont and /HeadFont
              The fonts used to draw the day numbers, the calendar entries, the small  calendars,
              the calendar title (month, year) and the day-of-the-week headings, respectively.

       DaySize, EntrySize, TitleSize and HeadSize
              The  sizes of the above fonts.  (The size of the small calendar font is not defined
              here.)  For example, if you wanted to print the Hebrew date next to the regular day
              number in the calendar, use:

            REM PS Border BoxHeight Border sub DaySize sub moveto \
               /DayFont findfont DaySize scalefont setfont \
               ([hebday(today())] [hebmon(today())]) show

              Note how /DayFont and DaySize are used.

       Note  that  if  you  supply  PostScript code, it is possible to produce invalid PostScript
       files.  Always test your PostScript thoroughly with a PostScript viewer before sending  it
       to  the  printer.  You should not use any document structuring comments in your PostScript
       code.

DAEMON MODE

       If you use the -z command-line option, Remind runs in the "daemon" mode.  In this mode, no
       "normal"  reminders  are  issued.  Instead, only timed reminders are collected and queued,
       and are then issued whenever they reach their trigger time.

       In addition, Remind wakes up every few minutes to  check  the  modification  date  on  the
       reminder  script  (the filename supplied on the command line.)  If Remind detects that the
       script has changed, it re-executes itself in  daemon  mode,  and  interprets  the  changed
       script.

       In  daemon  mode,  Remind  also re-reads the remind script when it detects that the system
       date has changed.

       In daemon mode, Remind acts as if the -f option had been used, so to  run  in  the  daemon
       mode in the background, use:

            remind -z .reminders &

       If  you  use sh or bash, you may have to use the "nohup" command to ensure that the daemon
       is not killed when you log out.

PURGE MODE

       If you supply the -j command-line option, Remind runs in purge mode.   In  this  mode,  it
       tries to purge expired reminders from your reminder files.

       In  purge  mode,  Remind  reads  your  reminder  file  and creates a new file by appending
       ".purged" to the original file name.  Note that Remind never edits your original file;  it
       always creates a new .purged file.

       If you invoke Remind against a directory instead of a file, then a .purged file is created
       for each *.rem file in the directory.

       Normally, Remind does not create .purged files for INCLUDed files.  However, if you supply
       a numeric argument after -j, then Remind will create .purged files for the specified level
       of INCLUDE.  For example, if you invoke Remind with the argument -j2, then  .purged  files
       will  be  created  for  the  file  (or directory) specified on the command line, any files
       included by them, and any files included by those files.  However, .purged files will  not
       be created for third-or-higher level INCLUDE files.

       Determining  which  reminders have expired is extremely tricky.  Remind does its best, but
       you should always compare the .purged file to the original file and hand-merge the changes
       back in.

       Remind annotates the .purged file as follows:

       An expired reminder is prefixed with:  #!P: Expired:

       In  situations  where Remind cannot reliably determine that something was expired, you may
       see the following comments inserted before the problematic line:

          #!P: Cannot purge SATISFY-type reminders

          #!P: The next IF evaluated false...
          #!P: REM statements in IF block not checked for purging.

          #!P: The previous IF evaluated true.
          #!P: REM statements in ELSE block not checked for purging

          #!P: The next IFTRIG did not trigger.
          #!P: REM statements in IFTRIG block not checked for purging.

          #!P: Next line has expired, but contains expression...  please verify

          #!P: Next line may have expired, but contains non-constant expression

          #!P! Could not parse next line: Some-Error-Message-Here

       Remind always annotates .purged files with lines beginning with "#!P".  If such lines  are
       encountered in the original file, they are not copied to the .purged file.

SORTING REMINDERS

       The  -g  option  causes Remind to sort reminders by trigger date, time and priority before
       issuing them.  Note that reminders are still calculated in the order  encountered  in  the
       script.   However,  rather  than  being  issued immediately, they are saved in an internal
       buffer.  When Remind has finished processing the script, it issues the saved reminders  in
       sorted order.  The -g option can be followed by up to four characters that must all be "a"
       or "d".  The first character specifies the  sort  order  by  trigger  date  (ascending  or
       descending),  the  second specifies the sort order by trigger time and the third specifies
       the sort order by priority.  If the fourth character is "d",  the  untimed  reminders  are
       sorted  before  timed reminders.  The default is to sort all fields in ascending order and
       to sort untimed reminders after timed reminders.

       In ascending order, reminders are issued with the most imminent first.   Descending  order
       is  the reverse.  Reminders are always sorted by trigger date, and reminders with the same
       trigger date are then sorted by trigger time.  If two reminders have  the  same  date  and
       time,  then  the  priority  is used to break ties.  Reminders with the same date, time and
       priority are issued in the order they were encountered.

       You can define  a  user-defined  function  called  SORTBANNER  that  takes  one  DATE-type
       argument.  In sort mode, the following sequence happens:

       If  Remind  notices  that the next reminder to issue has a different trigger date from the
       previous one (or if it is the first one to be issued), then SORTBANNER is called with  the
       trigger  date  as its argument.  The result is coerced to a string, and passed through the
       substitution filter with the appropriate trigger date.  The result is then displayed.

       Here's an example - consider the following fragment:

            # Switch off the normal banner
            BANNER %
            REM 11 March 1993 ++1 MSG Not so important
            REM 17 March 1993 ++7 MSG Way in the future
            REM 10 March 1993 MSG Important Reminder
            REM 11 March 1993 ++1 MSG Not so important - B
            FSET sortbanner(x) iif(x == today(), \
                 "***** THINGS TO DO TODAY *****", \
                 "----- Things to do %b -----")

       Running this with the -gaa option on 10 March 1993 produces the following output:

            ***** THINGS TO DO TODAY *****

            Important Reminder

            ----- Things to do tomorrow -----

            Not so important

            Not so important - B

            ----- Things to do in 7 days' time -----

            Way in the future

       You can use the args() built-in function to determine whether or not SORTBANNER  has  been
       defined.  (This could be used, for example, to provide a default definition for SORTBANNER
       in a system-wide file included at the end of the user's file.)  Here's an example:

            # Create a default sortbanner function if it hasn't already
            # been defined
            if args("sortbanner") != 1
                 fset sortbanner(x) "--- Things to do %b ---"
            endif

MSGPREFIX() AND MSGSUFFIX()

       You can define two functions in your script  called  msgprefix()  and  msgsuffix().   They
       should each accept one argument, a number from 0 to 9999.

       In normal mode, for MSG- and MSF-type reminders, the following sequence occurs when Remind
       triggers a reminder:

       o      If msgprefix() is defined, it is evaluated with the priority of the reminder as its
              argument.   The  result  is  printed.   It  is  not passed through the substitution
              filter.

       o      The body of the reminder is printed.

       o      If msgsuffix() is defined, it is evaluated with the priority of the reminder as its
              argument.   The  result  is  printed.   It  is  not passed through the substitution
              filter.

       Here's an example:  The following definition causes priority-0 reminders to be preceded by
       "URGENT", and priority-6000 reminders to be preceded by "(not important)".

            fset msgprefix(x) iif(x==0, "URGENT: ", \
                 x==6000, "(not important) ", "")

       In  Calendar  Mode  (with  the -c, -s or -p options), an analogous pair of functions named
       calprefix() and calsuffix() can be defined.  They work with all reminders that produce  an
       entry  in  the  calendar  (i.e.,  CAL- and possibly RUN-type reminders as well as MSG-type
       reminders.)

       NOTES

       Normally, the body of a reminder is followed by a carriage return.  Thus, the  results  of
       msgsuffix()  will  appear  on  the next line.  If you don't want this, end the body of the
       reminder with a percentage sign, "%".  If you want a space between your reminders,  simply
       include a carriage return (char(13)) as part of the msgsuffix() return value.

       If Remind has problems evaluating msgprefix(), msgsuffix() or sortbanner(), you will see a
       lot of error messages.  For an example of this, define the following:

            fset msgprefix(x) x/0

COMPILE-TIME SUPPORT FOR OTHER LANGUAGES

       Your version of Remind may have been compiled to support a language  other  than  English.
       This  support  may  or may not be complete - for example, all error and usage messages may
       still be in English.  However, at a minimum, non-English versions of  Remind  will  output
       names  of  months and weekdays in the selected language.  Also, the substitution mechanism
       will substitute constructs suitable for the selected language rather than for English.

       Note that a non-English version of Remind will accept only English names of  weekdays  and
       months in a reminder script.

RUN-TIME SUPPORT FOR OTHER LANGUAGES

       Remind  has  run-time  support  for  other languages, and it is expected that compile-time
       support will be deprecated in favour of run-time support.

       A number of system variables let you translate various phrases to other languages.   These
       system variables are:

       $Monday, $Tuesday, $Wednesday, $Thursday, $Friday, $Saturday, $Sunday
              Set each of these system variables to a string representing the corresponding day's
              name in your language.  Strings must be valid UTF-8 strings.

       $January, $February, $March, $April, $May, $June, $July,  $August,  $September,  $October,
       $November, $December
              Set  each  of  these  system  variables  to a string representing the corresponding
              month's name in your language.  Strings must be valid UTF-8 strings.

       $Ago, $Am, $And, $At, $Hour, $Is, $Minute, $Now, $On, $Pm, $Was
              Set each of these system variables to the translation of the corresponding  English
              word  into your language.  Note that $Am and $Pm should be the translations of "AM"
              and "PM" (morning and afternoon time indicators) respectively.

       $Hplu, $Mplu
              Set these to the suffix to add to the word for "hour" and  "minute"  to  make  them
              plural.  In English, both would be set to "s".

       $Fromnow
              Set this to the translation of the English phrase "from now"

       Note that if you set any of the language-related system variables, they should be set in a
       section of your script that always is evaluated.  If you set them inside an IF  statement,
       for example, results are unpredictable.

       Note  also  that  the Rem2PS back-end does not support the full range of UTF-8 characters.
       The TkRemind, rem2html and rem2pdf back-ends all do support the full UTF-8 range.

RUN-TIME MODIFICATION OF THE SUBSTITUTION FILTER

       The system variables mentioned in the previous section are  not  typically  sufficient  to
       properly  translate  Remind's output to another language.  Some languages have complicated
       rules for AM vs PM times and others have complex rules for making  words  plural.   Remind
       therefore  allows  you  to  define  a  number of functions that modify the behavior of the
       substitution filter at run-time.  The functions are:

       subst_ampm(h)
              This function is passed a single integer, namely an hour from 0 to 23.   It  should
              return  a  string  that  indicates  "AM"  or  "PM" or even finer gradations in some
              languages.

       subst_ordinal(d)
              This function is passed a single integer, namely a day of the month from 1  to  31.
              It  should  return  a  string that is suffixed to the day number to turn it into an
              ordinal number.  In English, for example, the function  might  return  "st",  "nd",
              "rd" or "th", depending on d.

       subst_N(alt, date, time)
              This  is  actually  a  family  of  functions,  where N is a letter or number.  This
              function completely overrides the substitution sequence "%N".  The three  arguments
              are   an  integer  alt  which,  if  non-zero,  indicates  that  the  alternate-mode
              substitution sequence "%*N" was encountered; date which is the trigger date of  the
              reminder and time which is the trigger time.

       subst_Nx(alt, date, time)
              Again,  this  is a family of functions.  It is similar to the subst_N family except
              it is only called if date is two or more days away from today().  This is useful if
              you  don't  want to override the "today" or "tomorrow" output for most substitution
              sequences.

       Here's an example of how you might customize your substitution filter.  Suppose  you  want
       to  change  the "%b" sequence to substitute "the day after tomorrow" for an event two days
       from now.  You could do this:

           FSET subst_bx(a,d,t) iif(d==today()+2, "the day after tomorrow", \
                                    "in " + (d-today()) + " days' time")
           REM [today()+3] ++3 MSG Event 1 is %b%
           REM [today()+2] ++3 MSG Event 2 is %b%
           REM [today()+1] ++3 MSG Event 3 is %b%
           REM [today()]   ++3 MSG Event 4 is %b%

       The output of this script is:

           Event 1 is in 3 days' time
           Event 2 is the day after tomorrow
           Event 3 is tomorrow
           Event 4 is today

       Note how Event 2's wording was changed from the normal "in 2 days' time",  and  note  also
       that  the  "tomorrow"  and  "today"  events used the normal substitution---subst_bx is not
       called for trigger days of today or tomorrow.

       As a special case, if a subst_Nx or subst_N function returns the integer  zero,  then  the
       normal  substitution  mechanism  is used.  Therefore, the previous example could have been
       written more simply as:

           FSET subst_bx(a,d,t) iif(d==today()+2, "the day after tomorrow", 0)

       You can define your own substitution  sequences  in  addition  to  the  built-in  ones  as
       follows:   If  you  define a function named subst_name(alt, date, time), then the sequence
       %{name} calls the function with alt set to 0 and date and time to  the  trigger  date  and
       time,  respectively.  The %{name} sequence is replaced with whatever the function returns.
       The sequence %*{name} is similar, but calls the function with alt set to 1.

       If you use a %{name} sequence and the function subst_name is not  defined  or  returns  an
       error, then %{name} is replaced with the empty string.

LANGUAGE PACKS

       Remind ships with a number of language packs, which are simply reminder scripts located in
       [$SysInclude]/lang.  The currently-shipping language packs are:

       da.rem (Danish), de.rem (German), es.rem (Spanish), fr.rem (French),  is.rem  (Icelandic),
       it.rem (Italian), nl.rem (Dutch), no.rem (Norwegian), pl.rem (Polish), pt.rem (Portuguese)
       and ro.rem (Romanian).

       To use a language pack (in this example, de.rem), simply place this at  the  top  of  your
       reminders file:

           INCLUDE [$SysInclude]/lang/de.rem

       If  you want Remind to try to find the language pack appropriate for your locale settings,
       use:

           INCLUDE [$SysInclude]/lang/auto.rem

       You are encouraged to study the language  packs  to  see  how  to  translate  Remind  into
       additional languages.

THE HEBREW CALENDAR

       Remind  has  support for the Hebrew calendar, which is a luni-solar calendar.  This allows
       you to create reminders for Jewish  holidays,  jahrzeits  (anniversaries  of  deaths)  and
       smachot (joyous occasions.)

       THE HEBREW YEAR

       The  Hebrew year has 12 months, alternately 30 and 29 days long.  The months are: Tishrey,
       Heshvan, Kislev, Tevet, Shvat, Adar, Nisan, Iyar, Sivan, Tamuz, Av and Elul.  In  Biblical
       times,  the year started in Nisan, but Rosh Hashana (Jewish New Year) is now celebrated on
       the 1st and 2nd of Tishrey.

       In a cycle of 19 years, there are 7 leap years, being years 3, 6, 8, 11, 14, 17 and 19  of
       the cycle.  In a leap year, an extra month of 30 days is added before Adar.  The two Adars
       are called Adar A and Adar B.

       For certain religious reasons, the year cannot start on a Sunday, Wednesday or Friday.  To
       adjust  for this, a day is taken off Kislev or added to Heshvan.  Thus, a regular year can
       have from 353 to 355 days, and a leap year from 383 to 385.

       When Kislev or Heshvan is short, it is called chaser, or lacking.  When it is long, it  is
       called shalem, or full.

       The  Jewish date changes at sunset.  However, Remind will change the date at midnight, not
       sunset.  So in the period between sunset and midnight, Remind will be a day  earlier  than
       the true Jewish date.  This should not be much of a problem in practice.

       The computations for the Jewish calendar were based on the program "hdate" written by Amos
       Shapir of the Hebrew University of Jerusalem, Israel.   He  also  supplied  the  preceding
       explanation of the calendar.

       HEBREW DATE FUNCTIONS

       hebday(d_date)
              Returns  the  day  of  the  Hebrew  month corresponding to the date parameter.  For
              example, 12 April 1993 corresponds to 21 Nisan  5753.   Thus,  hebday('1993/04/12')
              returns 21.

       hebmon(d_date)
              Returns  the  name  of  the  Hebrew  month  corresponding  to  date.   For example,
              hebmon('1993/04/12') returns "Nisan".

       hebyear(d_date)
              Returns the Hebrew year corresponding to date.  For example,  hebyear('1993/04/12')
              returns 5753.

       hebdate(i_day, s_hebmon [,id_yrstart [,i_jahr [,i_aflag]]])
              The hebdate() function is the most complex of the Hebrew support functions.  It can
              take from 2 to 5 arguments.  It returns a DATE corresponding to the Hebrew date.

              The day parameter can range from 1 to 30, and  specifies  the  day  of  the  Hebrew
              month.   The  hebmon  parameter is a string that must name one of the Hebrew months
              specified above.  Note that the month must be spelled out  in  full,  and  use  the
              English  transliteration shown previously.  You can also specify "Adar A" and "Adar
              B."  Month names are not case-sensitive.

              The yrstart parameter can either be a DATE or an INT.  If it is a  DATE,  then  the
              hebdate() scans for the first Hebrew date on or after that date.  For example:

                        hebdate(15, "Nisan", '1990/01/01')

              returns  1990/03/30, because that is the first occurrence of 15 Nisan on or after 1
              January 1990.

              If yrstart is an INT, it is interpreted as a Hebrew year.  Thus:

                        hebdate(22, "Kislev", 5756)

              returns 1995/12/15, because that date corresponds to 22 Kislev,  5756.   Note  that
              none  of  the  Hebrew  date  functions will work with dates outside Remind's normal
              range for dates.

              If yrstart is not supplied, it defaults to today().

              The jahr modifies the behaviour of hebdate() as follows:

              If jahr is 0 (the default), then hebdate() keeps scanning until  it  finds  a  date
              that exactly satisfies the other parameters.  For example:

                        hebdate(30, "Adar A", 1993/01/01)

              returns  1995/03/02,  corresponding  to  30  Adar A, 5755, because that is the next
              occurrence of 30 Adar A after 1 January, 1993.  This behaviour is  appropriate  for
              Purim Katan, which only appears in leap years.

              If jahr is 1, then the date is modified as follows:

              o      30 Heshvan is converted to 1 Kislev in years when Heshvan is chaser

              o      30 Kislev is converted to 1 Tevet in years when Kislev is chaser

              o      30 Adar A is converted to 1 Nisan in non-leapyears

              o      Other  dates  in  Adar  A are moved to the corresponding day in Adar in non-
                     leapyears

              This behaviour is appropriate for smachot (joyous occasions) and for some jahrzeits
              - see "JAHRZEITS."

              if jahr is 2, then the date is modified as follows:

              o      30  Kislev  and  30  Heshvan  are  converted  to  29  Kislev and 29 Heshvan,
                     respectively, if the month is chaser

              o      30 Adar A is converted to 30 Shvat in non-leapyears

              o      Other dates in Adar A are moved to the corresponding day  in  Adar  in  non-
                     leapyears

              if jahr is not 0, 1, or 2, it is interpreted as a Hebrew year, and the behaviour is
              calculated as described in the next section, "JAHRZEITS."

              The aflag parameter modifies the behaviour of the function for dates in Adar during
              leap years.  The aflag is only used if yrstart is a DATE type.

              The aflag only affects date calculations if hebmon is specified as "Adar".  In leap
              years, the following algorithm is followed:

              o      If aflag is 0, then the date is triggered in Adar B.  This is the default.

              o      If aflag is 1,  then  the  date  is  triggered  in  Adar  A.   This  may  be
                     appropriate for jahrzeits in the Ashkenazi tradition; consult a rabbi.

              o      If  aflag  is  2,  then the date is triggered in both Adar A and Adar B of a
                     leap year.  Some Ashkenazim perform jahrzeit in both Adar A and Adar B.

       JAHRZEITS

       A jahrzeit is a yearly commemoration of someone's death.  It normally takes place  on  the
       anniversary  of  the  death, but may be delayed if burial is delayed - consult a rabbi for
       more information.

       In addition, because  some  months  change  length,  it  is  not  obvious  which  day  the
       anniversary of a death is.  The following rules are used:

       o      If  the  death  occurred  on 30 Heshvan, and Heshvan in the year after the death is
              chaser, then the jahrzeit is observed on  29  Heshvan  in  years  when  Heshvan  is
              chaser.  Otherwise, the jahrzeit is observed on 1 Kislev when Heshvan is chaser.

       o      If  the  death  occurred  on  30  Kislev, and Kislev in the year after the death is
              chaser, then the jahrzeit is observed on 29 Kislev in years when Kislev is  chaser.
              Otherwise, the jahrzeit is observed on 1 Tevet when Kislev is chaser.

       o      If the death occurred on 1-29 Adar A, it is observed on 1-29 Adar in non-leapyears.

       o      If the death occurred on 30 Adar A, it is observed on 30 Shvat in a non-leapyear.

       Specifying  a  Hebrew  year  for  the  jahr  parameter  causes the correct behaviour to be
       selected for a death in that year.  You may also have to specify aflag, depending on  your
       tradition.

       The  jahrzeit  information  was  supplied  by  Frank Yellin, who quoted "The Comprehensive
       Hebrew Calendar" by Arthur Spier, and "Calendrical Calculations" by  E.  M.  Reingold  and
       Nachum Dershowitz.

OUT-OF-BAND REMINDERS

       The SPECIAL keyword is used to transmit "out-of-band" information to Remind backends, such
       as tkremind or Rem2PS.  They are used only when piping data from a remind -p line.   (Note
       that the COLOR special is an exception; it downgrades to the equivalent of MSG in Remind's
       normal mode of operation.)

       The various SPECIALs recognized are particular for each backend; however, there  are  four
       SPECIALs  that  all  backends  should attempt to support.  They are currently supported by
       Rem2PS, tkremind and rem2html.

       The SHADE special replaces the psshade() function.  Use it like this:

            REM Sat Sun SPECIAL SHADE 128
            REM Mon SPECIAL SHADE 255 0 0

       The SHADE keyword is followed by either one or three numbers,  from  0  to  255.   If  one
       number is supplied, it is interpreted as a grey-scale value from black (0) to white (255).
       If three numbers are supplied, they are interpreted as RGB components from minimum (0)  to
       maximum  (255).   The example above shades weekends a fairly dark grey and makes Mondays a
       fully-saturated red.  (These shadings appear in calendars produced by Rem2PS, tkremind and
       rem2html.)

       The MOON special replaces the psmoon() function.  Use it like this:

            REM [moondate(0)] SPECIAL MOON 0
            REM [moondate(1)] SPECIAL MOON 1
            REM [moondate(2)] SPECIAL MOON 2
            REM [moondate(3)] SPECIAL MOON 3

       These draw little moons on the various calendars.  The complete syntax of the MOON special
       is as follows:

            ... SPECIAL MOON phase moonsize fontsize msg

       Phase is a number from 0 to 3, with 0 representing a new moon, 1 the first  quarter,  2  a
       full moon and 3 the last quarter.

       moonsize  is the diameter in PostScript units of the moon to draw.  If omitted or supplied
       as -1, the backend chooses an appropriate size.

       fontsize is the font size in PostScript units of the msg

       Msg is additional text that is placed near the moon glyph.

       Note that only the Rem2PS backend supports moonsize and fontsize; the other  backends  use
       fixed sizes.

       The COLOR special lets you place colored reminders in the calendar.  Use it like this:

            REM ... SPECIAL COLOR 255 0 0 This is a bright red reminder
            REM ... SPECIAL COLOR 0 128 0 This is a dark green reminder

       You can spell COLOR either the American way ("COLOR") or the British way ("COLOUR").  This
       manual will use the American way.

       Immediately following COLOR should  be  three  decimal  numbers  ranging  from  0  to  255
       specifying  red,  green  and  blue intensities, respectively.  The rest of the line is the
       text to put in the calendar.

       The COLOR special is "doubly special", because in its normal operating mode, remind treats
       a  COLOR  special  just  like a MSG-type reminder.  Also, if you invoke Remind with -@[n],
       then it approximates SPECIAL COLOR reminders on your terminal.

       See also the documentation of the $DefaultColor system variable  in  the  section  "SYSTEM
       VARIABLES".

       The  WEEK special lets you place annotations such as the week number in the calendar.  For
       example, this would number each Monday with the ISO 8601 week number.  The week number  is
       shown  like this: "(Wn)" in this example, but you can put whatever text you like after the
       WEEK keyword.

            REM Monday SPECIAL WEEK (W[weekno()])

MISCELLANEOUS

       COMMAND AND KEYWORD ABBREVIATIONS

       The following tokens can be abbreviated:

       o      REM can be omitted - it is implied if no other valid command is present.

       o      CLEAR-OMIT-CONTEXT --> CLEAR

       o      PUSH-OMIT-CONTEXT --> PUSH

       o      POP-OMIT-CONTEXT --> POP

       o      DUMPVARS --> DUMP

       o      BANNER --> BAN

       o      INCLUDE --> INC

       o      MAYBE-UNCOMPUTABLE --> MAYBE

       o      SCANFROM --> SCAN

       NIFTY EXAMPLES

       This section is a sampling of what you can do with Remind.

            REM 5 Feb 1991 AT 14:00 +45 *30 \
            RUN mail -s "Meeting at %2" $LOGNAME </dev/null &

       On 5 February, 1991, this reminder will mail you reminders of a 2:00pm  meeting  at  1:15,
       1:45  and  2:00.  The subject of the mail message will be "Meeting at 2:00pm" and the body
       of the message will be blank.

            REM AT 17:00 RUN echo "5:00pm - GO HOME!" | xless -g +0+0 &

       This reminder will pop up an xless window at 5:00pm every  day.   The  xless  window  will
       contain the line "5:00pm - GO HOME!"

            REM AT 23:59 RUN (sleep 120; remind -a [filename()]) &

       This  reminder  will run at one minute to midnight.  It will cause a new Remind process to
       start at one minute past midnight.  This allows you to have a continuous reminder  service
       so  you can work through the night and still get timed reminders for early in the morning.
       Note that this trick is no longer necessary, providing you run Remind in daemon mode.

            remind -c12 /dev/null Jan 1993

       This invocation of Remind will cause it to print a calendar for  1993,  with  all  entries
       left blank.

            REM CAL [trigdate()-date(year(trigdate()), 1, 1)+1]

       This  example puts an entry in each box of a calendar showing the number (1-365 or 366) of
       the day of the year.

            REM Tue 2 Nov SATISFY (year(trigdate())%4) == 0
            IF trigvalid()
                 REM [trigdate()] ++5 MSG \
                 U.S. Presidential Election!!
            ENDIF

       This example warns you 5 days ahead of each American presidential election.  The first REM
       command  calculates  the  first  Tuesday  after  the  first  Monday in November.  (This is
       equivalent to the first Tuesday on or after 2 November.)  The SATISFY clause ensures  that
       the  trigger  date is issued only in election years, which are multiples of 4.  The second
       REM command actually issues the reminder.

       DETAILS ABOUT TRIGGER COMPUTATION

       Here is a conceptual description  of  how  triggers  are  calculated.   Note  that  Remind
       actually  uses  a  much  more  efficient procedure, but the results are the same as if the
       conceptual procedure had been followed.

       Remind starts from the current date (that is, the value of  today())  and  scans  forward,
       examining  each day one at a time until it finds a date that satisfies the trigger, or can
       prove that no such dates (on or later than today()) exist.

       If Remind  is  executing  a  SATISFY-type  reminder,  it  evaluates  the  expression  with
       trigdate()  set  to the date found above.  If the expression evaluates to zero or the null
       string, Remind continues the scanning procedure described above,  starting  with  the  day
       after the trigger found above.

       The  SCANFROM  clause  (having  a  syntax similar to UNTIL) can modify the search strategy
       used.  In this case, Remind begins the scanning procedure at scan_date, which is the  date
       specified in the SCANFROM clause.  For example:

            REM Mon 1 SCANFROM 17 Jan 1992 MSG Foo

       The  example  above  will  always have a trigger date of Monday, 3 February 1992.  That is
       because Remind starts scanning from 17 January 1992, and stops scanning as soon as it hits
       a date that satisfies "Mon 1."

       The  main  use  of  SCANFROM is in situations where you want to calculate the positions of
       floating holidays.  Consider the Labour Day example shown much earlier.  Labour Day is the
       first  Monday  in  September.  It can move over a range of 7 days.  Consider the following
       sequence:

            REM Mon 1 Sept SCANFROM [today()-7] ADDOMIT MSG Labour Day
            REM Mon AFTER MSG Hello

       The SCANFROM clause makes sure that Remind begins scanning from 7 days before the  current
       date.   This  ensures  that  Labour Day for the current year will continue to be triggered
       until 7 days after it has occurred.  This allows you to safely use the  AFTER  keyword  as
       shown.

       As  a special case, you can simply use a negative number after SCANFROM; a negative number
       -N is interpreted as N days before today.   Thus,  the  previous  example  could  also  be
       written like this:

            REM Mon 1 Sept SCANFROM -7 ADDOMIT MSG Labour Day
            REM Mon AFTER MSG Hello

       In general, use SCANFROM as shown for safe movable OMITs.  The amount you should scan back
       by (7 days in the example above) depends on the number  of  possible  consecutive  OMITted
       days  that may occur, and on the range of the movable holiday.  Generally, a value of 7 is
       safe.

       The FROM clause operates almost like the counterpoint to UNTIL.  It prevents the  reminder
       from triggering before the FROM date.  For example, the following reminder:

            REM Mon Thu FROM 23 Jul 2007 UNTIL 2 Aug 2007 MSG Test

       will trigger on Mondays and Thursdays between 23 July 2007 and 2 August 2007 inclusive.

       FROM is really just syntactic sugar; you could implement the reminder above as follows:

            REM Mon Thu SCANFROM [max(today(), '2007-07-23')] \
                   UNTIL 2 Aug 2007 MSG Test

       but  that's  a  lot harder to read.  Internally, Remind treats FROM exactly as illustrated
       using SCANFROM.  For that reason, you cannot use both FROM and SCANFROM.

       Note that if  you  use  one  REM  command  to  calculate  a  trigger  date,  perform  date
       calculations  (addition  or  subtraction, for example) and then use the modified date in a
       subsequent REM command, the results may not be what you intended.   This  is  because  you
       have  circumvented  the  normal  scanning mechanism.  You should try to write REM commands
       that compute trigger dates that can be used unmodified in subsequent  REM  commands.   The
       file "defs.rem" that comes with the Remind distribution contains examples.

       DETAILS ABOUT TRIGVALID()

       The  trigvalid()  function  returns 1 if Remind could find a trigger date for the previous
       REM or IFTRIG command.  More specifically, it returns 1 if Remind finds a date not  before
       the  starting  date of the scanning that satisfies the trigger.  In addition, there is one
       special case in which trigvalid() returns 1 and trigdate() returns a meaningful result:

       If the REM or IFTRIG command did not contain an UNTIL clause, and  contained  all  of  the
       day, month and year components, then Remind will correctly compute a trigger date, even if
       it happens to be before the start of scanning.  Note that this behaviour is not  true  for
       versions of Remind prior to 03.00.01.

FILES

       The traditional location of your reminders file or directory is:

               $HOME/.reminders

       where $HOME is your home directory.

       Remind  ships  with  some  preinstalled  files for holidays and language packs.  These are
       located in the following directory:

               /usr/share/remind/

       Do not hard-code the above directory in your reminder files.  Instead, use  the  value  of
       the $SysInclude system variable.

AUTHOR

       Dianne  Skoll <dianne@skoll.ca> wrote Remind.  The moon code was copied largely unmodified
       from "moontool" by John Walker.  The sunrise and sunset functions use ideas from  programs
       by  Michael  Schwartz  and  Marc  T.  Kaufman.  The Hebrew calendar support was taken from
       "hdate" by Amos Shapir.  OS/2 support was done  by  Darrel  Hankerson,  Russ  Herman,  and
       Norman  Walsh.  The supported languages and their translators are listed below.  Languages
       marked "complete" support error messages and usage  instructions  in  that  language;  all
       others only support the substitution filter mechanism and month/day names.

       German -- Wolfgang Thronicke

       Dutch -- Willem Kasdorp and Erik-Jan Vens

       Finnish -- Mikko Silvonen (complete)

       French -- Laurent Duperval (complete)

       Norwegian -- Trygve Randen

       Danish -- Mogens Lynnerup

       Polish -- Jerzy Sobczyk (complete)

       Brazilian Portuguese -- Marco Paganini (complete)

       Italian -- Valerio Aimale

       Romanian -- Liviu Daia

       Spanish -- Rafa Couto

       Icelandic -- Björn Davíðsson

BUGS

       If you find a bug in Remind, please report it to: dianne@skoll.ca

       There's no good reason why read-only system variables are not implemented as functions, or
       why functions like version(), etc.  are not implemented as read-only system variables.

       Hebrew dates in Remind change at midnight instead of sunset.

       Remind has some built-in limits (for example, number of global OMITs.)

BIBLIOGRAPHY

       Nachum Dershowitz and Edward M. Reingold,  "Calendrical  Calculations",  Software-Practice
       and Experience, Vol. 20(9), Sept. 1990, pp 899-928.

       L. E. Doggett, Almanac for computers for the year 1978, Nautical Almanac Office, USNO.

       Richard  Siegel  and  Michael  and  Sharon  Strassfeld,  The  First Jewish Catalog, Jewish
       Publication Society of America.

       Jean Meeus, Astronomical Algorithms, Second Edition, Willmann-Bell, Inc.

HOME PAGE

       https://dianne.skoll.ca/projects/remind/

MAILING LIST

       https://dianne.skoll.ca/mailman/listinfo/remind-fans

SEE ALSO

       rem(1), rem2ps(1), rem2pdf(1), tkremind(1), rem2html(1)