trusty (1) less.1.gz

Provided by: less_458-2_amd64 bug

NAME

       less - opposite of more

SYNOPSIS

       less -?
       less --help
       less -V
       less --version
       less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
            [-b space] [-h lines] [-j line] [-k keyfile]
            [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
            [-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
            [-# shift] [+[+]cmd] [--] [filename]...
       (See the OPTIONS section for alternate option syntax with long option names.)

DESCRIPTION

       Less  is  a  program  similar to more (1), but it has many more features.  Less does not have to read the
       entire input file before starting, so with large input files it starts up faster than text  editors  like
       vi (1).  Less uses termcap (or terminfo on some systems), so it can run on a variety of terminals.  There
       is even limited support for hardcopy terminals.  (On a hardcopy terminal, lines which should  be  printed
       at the top of the screen are prefixed with a caret.)

       Commands  are  based  on both more and vi.  Commands may be preceded by a decimal number, called N in the
       descriptions below.  The number is used by some commands, as indicated.

COMMANDS

       In the following descriptions, ^X means control-X.  ESC stands for the  ESCAPE  key;  for  example  ESC-v
       means the two character sequence "ESCAPE", then "v".

       h or H Help:  display  a  summary of these commands.  If you forget all the other commands, remember this
              one.

       SPACE or ^V or f or ^F
              Scroll forward N lines, default one window (see option -z below).  If N is more  than  the  screen
              size,  only  the  final  screenful  is  displayed.   Warning:  some  systems  use  ^V as a special
              literalization character.

       z      Like SPACE, but if N is specified, it becomes the new window size.

       ESC-SPACE
              Like SPACE, but scrolls a full screenful, even if it reaches end-of-file in the process.

       ENTER or RETURN or ^N or e or ^E or j or ^J
              Scroll forward N lines, default 1.  The entire N lines are displayed, even if N is more  than  the
              screen size.

       d or ^D
              Scroll  forward  N  lines, default one half of the screen size.  If N is specified, it becomes the
              new default for subsequent d and u commands.

       b or ^B or ESC-v
              Scroll backward N lines, default one window (see option -z below).  If N is more than  the  screen
              size, only the final screenful is displayed.

       w      Like ESC-v, but if N is specified, it becomes the new window size.

       y or ^Y or ^P or k or ^K
              Scroll  backward N lines, default 1.  The entire N lines are displayed, even if N is more than the
              screen size.  Warning: some systems use ^Y as a special job control character.

       u or ^U
              Scroll backward N lines, default one half of the screen size.  If N is specified, it  becomes  the
              new default for subsequent d and u commands.

       ESC-) or RIGHTARROW
              Scroll  horizontally  right N characters, default half the screen width (see the -# option).  If a
              number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands.  While
              the text is scrolled, it acts as though the -S option (chop lines) were in effect.

       ESC-( or LEFTARROW
              Scroll  horizontally  left  N characters, default half the screen width (see the -# option).  If a
              number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands.

       r or ^R or ^L
              Repaint the screen.

       R      Repaint the screen, discarding any buffered input.  Useful if the file is  changing  while  it  is
              being viewed.

       F      Scroll  forward,  and  keep trying to read when the end of file is reached.  Normally this command
              would be used when already at the end of the file.  It is a way to monitor  the  tail  of  a  file
              which is growing while it is being viewed.  (The behavior is similar to the "tail -f" command.)

       ESC-F  Like F, but as soon as a line is found which matches the last search pattern, the terminal bell is
              rung and forward scrolling stops.

       g or < or ESC-<
              Go to line N in the file, default 1 (beginning of file).  (Warning: this  may  be  slow  if  N  is
              large.)

       G or > or ESC->
              Go  to line N in the file, default the end of the file.  (Warning: this may be slow if N is large,
              or if N is not specified and standard input, rather than a file, is being read.)

       p or % Go to a position N percent into the file.  N should be between  0  and  100,  and  may  contain  a
              decimal point.

       P      Go to the line containing byte offset N in the file.

       {      If  a left curly bracket appears in the top line displayed on the screen, the { command will go to
              the matching right curly bracket.  The matching right curly bracket is positioned  on  the  bottom
              line  of the screen.  If there is more than one left curly bracket on the top line, a number N may
              be used to specify the N-th bracket on the line.

       }      If a right curly bracket appears in the bottom line displayed on the screen, the } command will go
              to the matching left curly bracket.  The matching left curly bracket is positioned on the top line
              of the screen.  If there is more than one right curly bracket on the top line, a number N  may  be
              used to specify the N-th bracket on the line.

       (      Like {, but applies to parentheses rather than curly brackets.

       )      Like }, but applies to parentheses rather than curly brackets.

       [      Like {, but applies to square brackets rather than curly brackets.

       ]      Like }, but applies to square brackets rather than curly brackets.

       ESC-^F Followed  by  two characters, acts like {, but uses the two characters as open and close brackets,
              respectively.  For example, "ESC ^F < >" could be used to go forward to the > which matches the  <
              in the top displayed line.

       ESC-^B Followed  by  two characters, acts like }, but uses the two characters as open and close brackets,
              respectively.  For example, "ESC ^B < >" could be used to go backward to the < which matches the >
              in the bottom displayed line.

       m      Followed by any lowercase letter, marks the current position with that letter.

       '      (Single  quote.)   Followed  by any lowercase letter, returns to the position which was previously
              marked with that letter.  Followed by another single quote, returns to the position at  which  the
              last  "large"  movement command was executed.  Followed by a ^ or $, jumps to the beginning or end
              of the file respectively.  Marks are preserved when a new file is examined, so the '  command  can
              be used to switch between input files.

       ^X^X   Same as single quote.

       /pattern
              Search  forward  in  the  file  for  the  N-th line containing the pattern.  N defaults to 1.  The
              pattern is a regular expression, as recognized by the regular expression library supplied by  your
              system.   The  search  starts  at  the  first line displayed (but see the -a and -j options, which
              change this).

              Certain characters are special if entered at the beginning of the pattern; they modify the type of
              search rather than become part of the pattern:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search  multiple files.  That is, if the search reaches the END of the current file without
                     finding a match, the search continues in the next file in the command line list.

              ^F or @
                     Begin the search at the first line of the FIRST file in the command line  list,  regardless
                     of what is currently displayed on the screen or the settings of the -a or -j options.

              ^K     Highlight  any  text which matches the pattern on the current screen, but don't move to the
                     first match (KEEP current position).

              ^R     Don't interpret regular expression metacharacters; that is, do a simple textual comparison.

       ?pattern
              Search backward in the file for the N-th line containing the pattern.  The search  starts  at  the
              line immediately before the top line displayed.

              Certain characters are special as in the / command:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search  multiple  files.   That is, if the search reaches the beginning of the current file
                     without finding a match, the search continues in the previous  file  in  the  command  line
                     list.

              ^F or @
                     Begin  the search at the last line of the last file in the command line list, regardless of
                     what is currently displayed on the screen or the settings of the -a or -j options.

              ^K     As in forward searches.

              ^R     As in forward searches.

       ESC-/pattern
              Same as "/*".

       ESC-?pattern
              Same as "?*".

       n      Repeat previous search, for N-th line containing the last pattern.  If  the  previous  search  was
              modified  by ^N, the search is made for the N-th line NOT containing the pattern.  If the previous
              search was modified by ^E, the search continues in the next (or previous) file if not satisfied in
              the  current  file.   If  the previous search was modified by ^R, the search is done without using
              regular expressions.  There is no effect if the previous search was modified by ^F or ^K.

       N      Repeat previous search, but in the reverse direction.

       ESC-n  Repeat previous search, but crossing file boundaries.  The effect is as  if  the  previous  search
              were modified by *.

       ESC-N  Repeat previous search, but in the reverse direction and crossing file boundaries.

       ESC-u  Undo  search  highlighting.  Turn off highlighting of strings matching the current search pattern.
              If highlighting is already off because of a previous ESC-u command,  turn  highlighting  back  on.
              Any  search  command  will  also turn highlighting back on.  (Highlighting can also be disabled by
              toggling the -G option; in that case search commands do not turn highlighting back on.)

       &pattern
              Display only lines which match the  pattern;  lines  which  do  not  match  the  pattern  are  not
              displayed.   If  pattern  is empty (if you type & immediately followed by ENTER), any filtering is
              turned off, and all lines are displayed.  While filtering is in effect, an ampersand is  displayed
              at the beginning of the prompt, as a reminder that some lines in the file may be hidden.

              Certain characters are special as in the / command:

              ^N or !
                     Display only lines which do NOT match the pattern.

              ^R     Don't interpret regular expression metacharacters; that is, do a simple textual comparison.

       :e [filename]
              Examine  a  new  file.  If the filename is missing, the "current" file (see the :n and :p commands
              below) from the list of files in the command line is re-examined.   A  percent  sign  (%)  in  the
              filename is replaced by the name of the current file.  A pound sign (#) is replaced by the name of
              the previously examined file.  However, two consecutive percent signs are simply replaced  with  a
              single  percent  sign.   This  allows  you to enter a filename that contains a percent sign in the
              name.  Similarly, two consecutive pound signs are replaced with a single pound sign.  The filename
              is  inserted  into  the  command line list of files so that it can be seen by subsequent :n and :p
              commands.  If the filename consists of several files, they are all inserted into the list of files
              and  the  first one is examined.  If the filename contains one or more spaces, the entire filename
              should be enclosed in double quotes (also see the -" option).

       ^X^V or E
              Same as :e.  Warning: some systems use ^V as a special literalization character.  On such systems,
              you may not be able to use ^V.

       :n     Examine  the  next  file  (from  the  list  of files given in the command line).  If a number N is
              specified, the N-th next file is examined.

       :p     Examine the previous file in the command line list.  If a number N is specified, the N-th previous
              file is examined.

       :x     Examine the first file in the command line list.  If a number N is specified, the N-th file in the
              list is examined.

       :d     Remove the current file from the list of files.

       t      Go to the next tag, if there were more than one matches for the current tag.  See  the  -t  option
              for more details about tags.

       T      Go to the previous tag, if there were more than one matches for the current tag.

       = or ^G or :f
              Prints  some  information  about the file being viewed, including its name and the line number and
              byte offset of the bottom line being displayed.  If possible, it also prints  the  length  of  the
              file, the number of lines in the file and the percent of the file above the last displayed line.

       -      Followed  by  one  of  the  command  line option letters (see OPTIONS below), this will change the
              setting of that option and print a message describing the new setting.  If  a  ^P  (CONTROL-P)  is
              entered  immediately  after  the  dash,  the  setting  of  the option is changed but no message is
              printed.  If the option letter has a numeric value (such as -b or -h), or a string value (such  as
              -P  or  -t),  a  new  value may be entered after the option letter.  If no new value is entered, a
              message describing the current setting is printed and nothing is changed.

       --     Like the - command, but takes a long option name (see OPTIONS below) rather than a  single  option
              letter.   You must press ENTER or RETURN after typing the option name.  A ^P immediately after the
              second dash suppresses printing of a message describing the new setting, as in the - command.

       -+     Followed by one of the command line option letters this will  reset  the  option  to  its  default
              setting and print a message describing the new setting.  (The "-+X" command does the same thing as
              "-+X" on the command line.)  This does not work for string-valued options.

       --+    Like the -+ command, but takes a long option name rather than a single option letter.

       -!     Followed by one of the command line option letters, this will reset the option to  the  "opposite"
              of  its  default  setting  and print a message describing the new setting.  This does not work for
              numeric or string-valued options.

       --!    Like the -! command, but takes a long option name rather than a single option letter.

       _      (Underscore.)  Followed by one of the command line option  letters,  this  will  print  a  message
              describing the current setting of that option.  The setting of the option is not changed.

       __     (Double  underscore.)  Like the _ (underscore) command, but takes a long option name rather than a
              single option letter.  You must press ENTER or RETURN after typing the option name.

       +cmd   Causes the specified cmd to be executed each time a new file is examined.  For example, +G  causes
              less to initially display each file starting at the end rather than the beginning.

       V      Prints the version number of less being run.

       q or Q or :q or :Q or ZZ
              Exits less.

       The following four commands may or may not be valid, depending on your particular installation.

       v      Invokes an editor to edit the current file being viewed.  The editor is taken from the environment
              variable VISUAL if defined, or EDITOR if VISUAL is not defined, or defaults  to  "vi"  if  neither
              VISUAL  nor  EDITOR  is defined.  See also the discussion of LESSEDIT under the section on PROMPTS
              below.

       ! shell-command
              Invokes a shell to run the shell-command given.  A percent sign (%) in the command is replaced  by
              the name of the current file.  A pound sign (#) is replaced by the name of the previously examined
              file.  "!!" repeats the last shell command.  "!" with no shell command simply invokes a shell.  On
              Unix systems, the shell is taken from the environment variable SHELL, or defaults to "sh".  On MS-
              DOS and OS/2 systems, the shell is the normal command processor.

       | <m> shell-command
              <m> represents any mark letter.  Pipes a section of the input file to  the  given  shell  command.
              The  section  of  the  file  to  be  piped is between the first line on the current screen and the
              position marked by the letter.  <m> may also be ^ or $  to  indicate  beginning  or  end  of  file
              respectively.  If <m> is . or newline, the current screen is piped.

       s filename
              Save the input to a file.  This only works if the input is a pipe, not an ordinary file.

OPTIONS

       Command line options are described below.  Most options may be changed while less is running, via the "-"
       command.

       Most options may be given in one of two forms: either a dash followed by a single letter, or  two  dashes
       followed  by  a  long  option name.  A long option name may be abbreviated as long as the abbreviation is
       unambiguous.  For example, --quit-at-eof may be abbreviated --quit, but not --qui, since both  --quit-at-
       eof  and  --quiet  begin  with --qui.  Some long option names are in uppercase, such as --QUIT-AT-EOF, as
       distinct from --quit-at-eof.  Such option names need  only  have  their  first  letter  capitalized;  the
       remainder of the name may be in either case.  For example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.

       Options are also taken from the environment variable "LESS".  For example, to avoid typing "less -options
       ..." each time less is invoked, you might tell csh:

       setenv LESS "-options"

       or if you use sh:

       LESS="-options"; export LESS

       On MS-DOS, you don't need the quotes, but you should replace any percent signs in the options  string  by
       double percent signs.

       The  environment  variable  is  parsed before the command line, so command line options override the LESS
       environment variable.  If an option appears in the LESS variable, it can be reset to its default value on
       the command line by beginning the command line option with "-+".

       Some  options  like -k or -D require a string to follow the option letter.  The string for that option is
       considered to end when a dollar sign ($) is found.  For example, you can set two  -D  options  on  MS-DOS
       like this:

       LESS="Dn9.1$Ds4.1"

       If  the  --use-backslash  option  appears  earlier in the options, then a dollar sign or backslash may be
       included literally in an option string by preceding it with a backslash.  If the  --use-backslash  option
       is  not  in  effect,  then backslashes are not treated specially, and there is no way to include a dollar
       sign in the option string.

       -? or --help
              This option displays a summary of the commands accepted by less  (the  same  as  the  h  command).
              (Depending  on  how  your  shell  interprets  the  question mark, it may be necessary to quote the
              question mark, thus: "-\?".)

       -a or --search-skip-screen
              By default, forward searches start at the top of the displayed screen and backwards searches start
              at  the  bottom  of  the  displayed  screen  (except  for  repeated searches invoked by the n or N
              commands, which start after or before the "target" line respectively; see the -j option  for  more
              about  the  target line).  The -a option causes forward searches to instead start at the bottom of
              the screen and backward searches to start at the top  of  the  screen,  thus  skipping  all  lines
              displayed on the screen.

       -A or --SEARCH-SKIP-SCREEN
              Causes  all forward searches (not just non-repeated searches) to start just after the target line,
              and all backward searches to start just before the target line.  Thus, forward searches will  skip
              part of the displayed screen (from the first line up to and including the target line).  Similarly
              backwards searches will skip the displayed screen from the last  line  up  to  and  including  the
              target line.  This was the default behavior in less versions prior to 441.

       -bn or --buffers=n
              Specifies  the  amount  of  buffer  space less will use for each file, in units of kilobytes (1024
              bytes).  By default 64K of buffer space is used for each file (unless the file is a pipe; see  the
              -B  option).   The -b option specifies instead that n kilobytes of buffer space should be used for
              each file.  If n is -1, buffer space is unlimited; that is, the  entire  file  can  be  read  into
              memory.

       -B or --auto-buffers
              By  default,  when  data is read from a pipe, buffers are allocated automatically as needed.  If a
              large amount of data is read from the pipe, this  can  cause  a  large  amount  of  memory  to  be
              allocated.   The  -B  option disables this automatic allocation of buffers for pipes, so that only
              64K (or the amount of space specified by the -b option) is used for the pipe.  Warning: use of  -B
              can  result  in  erroneous  display, since only the most recently viewed part of the piped data is
              kept in memory; any earlier data is lost.

       -c or --clear-screen
              Causes full screen repaints to be painted from  the  top  line  down.   By  default,  full  screen
              repaints are done by scrolling from the bottom of the screen.

       -C or --CLEAR-SCREEN
              Same as -c, for compatibility with older versions of less.

       -d or --dumb
              The  -d  option  suppresses the error message normally displayed if the terminal is dumb; that is,
              lacks some important capability, such as the ability to clear the screen or scroll backward.   The
              -d option does not otherwise change the behavior of less on a dumb terminal.

       -Dxcolor or --color=xcolor
              [MS-DOS  only]  Sets  the  color of the text displayed.  x is a single character which selects the
              type of text whose color is being set: n=normal, s=standout, d=bold, u=underlined, k=blink.  color
              is a pair of numbers separated by a period.  The first number selects the foreground color and the
              second selects the background color of the text.  A single number N is the same as N.M, where M is
              the normal background color.

       -e or --quit-at-eof
              Causes  less  to  automatically exit the second time it reaches end-of-file.  By default, the only
              way to exit less is via the "q" command.

       -E or --QUIT-AT-EOF
              Causes less to automatically exit the first time it reaches end-of-file.

       -f or --force
              Forces non-regular files to be opened.  (A non-regular file is a directory  or  a  device  special
              file.)   Also  suppresses the warning message when a binary file is opened.  By default, less will
              refuse to open non-regular files.  Note that some operating systems will not allow directories  to
              be read, even if -f is set.

       -F or --quit-if-one-screen
              Causes less to automatically exit if the entire file can be displayed on the first screen.

       -g or --hilite-search
              Normally,  less  will  highlight  ALL  strings which match the last search command.  The -g option
              changes this behavior to highlight only the particular string which was found by the  last  search
              command.  This can cause less to run somewhat faster than the default.

       -G or --HILITE-SEARCH
              The -G option suppresses all highlighting of strings found by search commands.

       -hn or --max-back-scroll=n
              Specifies  a  maximum  number  of lines to scroll backward.  If it is necessary to scroll backward
              more than n lines, the screen is repainted in a forward direction instead.  (If the terminal  does
              not have the ability to scroll backward, -h0 is implied.)

       -i or --ignore-case
              Causes  searches  to ignore case; that is, uppercase and lowercase are considered identical.  This
              option is ignored if any uppercase letters appear in the search pattern;  in  other  words,  if  a
              pattern contains uppercase letters, then that search does not ignore case.

       -I or --IGNORE-CASE
              Like -i, but searches ignore case even if the pattern contains uppercase letters.

       -jn or --jump-target=n
              Specifies  a  line  on the screen where the "target" line is to be positioned.  The target line is
              the line specified by any command to search for a pattern, jump to a line number, jump to  a  file
              percentage  or  jump  to a tag.  The screen line may be specified by a number: the top line on the
              screen is 1, the next is 2, and so on.  The number may be negative to specify a line  relative  to
              the bottom of the screen: the bottom line on the screen is -1, the second to the bottom is -2, and
              so on.  Alternately, the screen line may be specified as a fraction of the height of  the  screen,
              starting with a decimal point: .5 is in the middle of the screen, .3 is three tenths down from the
              first line, and so on.  If the line is  specified  as  a  fraction,  the  actual  line  number  is
              recalculated  if  the terminal window is resized, so that the target line remains at the specified
              fraction of the screen height.  If any form of the -j option is used, forward  searches  begin  at
              the line immediately after the target line, and backward searches begin at the target line, unless
              changed by -a or -A.  For example, if "-j4" is used, the target line is the  fourth  line  on  the
              screen, so forward searches begin at the fifth line on the screen.

       -J or --status-column
              Displays  a  status column at the left edge of the screen.  The status column shows the lines that
              matched the current search.  The status column is also used if the -w or -W option is in effect.

       -kfilename or --lesskey-file=filename
              Causes less to open and interpret the named file as a lesskey (1) file.  Multiple -k  options  may
              be  specified.  If the LESSKEY or LESSKEY_SYSTEM environment variable is set, or if a lesskey file
              is found in a standard place (see KEY BINDINGS), it is also used as a lesskey file.

       -K or --quit-on-intr
              Causes less to exit immediately (with status 2) when an interrupt character (usually ^C) is typed.
              Normally,  an  interrupt  character  causes  less  to  stop whatever it is doing and return to its
              command prompt.  Note that use of this option makes it impossible to return to the command  prompt
              from the "F" command.

       -L or --no-lessopen
              Ignore  the LESSOPEN environment variable (see the INPUT PREPROCESSOR section below).  This option
              can be set from within less, but it will apply only to files opened subsequently, not to the  file
              which is currently open.

       -m or --long-prompt
              Causes  less  to  prompt  verbosely (like more), with the percent into the file.  By default, less
              prompts with a colon.

       -M or --LONG-PROMPT
              Causes less to prompt even more verbosely than more.

       -n or --line-numbers
              Suppresses line numbers.  The default (to use line numbers) may cause less to run more  slowly  in
              some  cases, especially with a very large input file.  Suppressing line numbers with the -n option
              will avoid this problem.  Using line numbers means: the line  number  will  be  displayed  in  the
              verbose  prompt  and  in the = command, and the v command will pass the current line number to the
              editor (see also the discussion of LESSEDIT in PROMPTS below).

       -N or --LINE-NUMBERS
              Causes a line number to be displayed at the beginning of each line in the display.

       -ofilename or --log-file=filename
              Causes less to copy its input to the named file as it is being viewed.  This applies only when the
              input  file  is  a  pipe,  not  an  ordinary  file.  If the file already exists, less will ask for
              confirmation before overwriting it.

       -Ofilename or --LOG-FILE=filename
              The -O option is like -o, but it will overwrite an existing file without asking for confirmation.

              If no log file has been specified, the -o and -O options can be used from within less to specify a
              log file.  Without a file name, they will simply report the name of the log file.  The "s" command
              is equivalent to specifying -o from within less.

       -ppattern or --pattern=pattern
              The -p option on the command line is equivalent to specifying +/pattern; that is, it tells less to
              start at the first occurrence of pattern in the file.

       -Pprompt or --prompt=prompt
              Provides  a  way  to  tailor  the  three  prompt styles to your own preference.  This option would
              normally be put in the LESS environment variable, rather  than  being  typed  in  with  each  less
              command.   Such an option must either be the last option in the LESS variable, or be terminated by
              a dollar sign.  -Ps followed by a string changes the default (short) prompt to that  string.   -Pm
              changes the medium (-m) prompt.  -PM changes the long (-M) prompt.  -Ph changes the prompt for the
              help screen.  -P= changes the message printed by the = command.  -Pw changes the  message  printed
              while  waiting  for  data (in the F command).  All prompt strings consist of a sequence of letters
              and special escape sequences.  See the section on PROMPTS for more details.

       -q or --quiet or --silent
              Causes moderately "quiet" operation: the terminal bell is not rung if an attempt is made to scroll
              past  the  end  of  the  file  or before the beginning of the file.  If the terminal has a "visual
              bell", it is used instead.  The bell will be rung on certain  other  errors,  such  as  typing  an
              invalid character.  The default is to ring the terminal bell in all such cases.

       -Q or --QUIET or --SILENT
              Causes totally "quiet" operation: the terminal bell is never rung.

       -r or --raw-control-chars
              Causes  "raw"  control  characters  to be displayed.  The default is to display control characters
              using the caret notation; for example, a control-A (octal 001) is  displayed  as  "^A".   Warning:
              when  the  -r option is used, less cannot keep track of the actual appearance of the screen (since
              this depends on how the screen responds to each type of control character).  Thus, various display
              problems may result, such as long lines being split in the wrong place.

       -R or --RAW-CONTROL-CHARS
              Like  -r,  but only ANSI "color" escape sequences are output in "raw" form.  Unlike -r, the screen
              appearance is maintained correctly in most cases.  ANSI "color" escape sequences are sequences  of
              the form:

                   ESC [ ... m

              where the "..." is zero or more color specification characters For the purpose of keeping track of
              screen appearance, ANSI color escape sequences are assumed to not move the cursor.  You  can  make
              less  think  that  characters  other  than  "m" can end ANSI color escape sequences by setting the
              environment variable LESSANSIENDCHARS to the list of characters  which  can  end  a  color  escape
              sequence.   And  you  can  make less think that characters other than the standard ones may appear
              between the ESC and the m by setting the environment variable  LESSANSIMIDCHARS  to  the  list  of
              characters which can appear.

       -s or --squeeze-blank-lines
              Causes  consecutive  blank  lines  to  be  squeezed into a single blank line.  This is useful when
              viewing nroff output.

       -S or --chop-long-lines
              Causes lines longer than the screen width to be chopped (truncated) rather than wrapped.  That is,
              the  portion of a long line that does not fit in the screen width is not shown.  The default is to
              wrap long lines; that is, display the remainder on the next line.

       -ttag or --tag=tag
              The -t option, followed immediately by a TAG, will edit the file containing that tag.  For this to
              work, tag information must be available; for example, there may be a file in the current directory
              called "tags", which was previously  built  by  ctags  (1)  or  an  equivalent  command.   If  the
              environment  variable  LESSGLOBALTAGS  is  set, it is taken to be the name of a command compatible
              with   global   (1),   and   that   command   is    executed    to    find    the    tag.     (See
              http://www.gnu.org/software/global/global.html).   The -t option may also be specified from within
              less (using the - command) as a way of examining a new file.  The command ":t"  is  equivalent  to
              specifying -t from within less.

       -Ttagsfile or --tag-file=tagsfile
              Specifies a tags file to be used instead of "tags".

       -u or --underline-special
              Causes  backspaces  and  carriage returns to be treated as printable characters; that is, they are
              sent to the terminal when they appear in the input.

       -U or --UNDERLINE-SPECIAL
              Causes backspaces, tabs and carriage returns to be treated as control characters;  that  is,  they
              are handled as specified by the -r option.

              By  default,  if  neither  -u  nor  -U is given, backspaces which appear adjacent to an underscore
              character are treated specially: the underlined text is displayed using  the  terminal's  hardware
              underlining  capability.   Also,  backspaces  which  appear  between  two identical characters are
              treated specially:  the  overstruck  text  is  printed  using  the  terminal's  hardware  boldface
              capability.   Other  backspaces are deleted, along with the preceding character.  Carriage returns
              immediately followed by a newline are deleted.  Other carriage returns are handled as specified by
              the -r option.  Text which is overstruck or underlined can be searched for if neither -u nor -U is
              in effect.

       -V or --version
              Displays the version number of less.

       -w or --hilite-unread
              Temporarily highlights the first "new" line after a forward movement of a full  page.   The  first
              "new"  line  is  the  line  immediately following the line previously at the bottom of the screen.
              Also highlights the target line after a g or p command.  The highlight  is  removed  at  the  next
              command which causes movement.  The entire line is highlighted, unless the -J option is in effect,
              in which case only the status column is highlighted.

       -W or --HILITE-UNREAD
              Like -w, but temporarily highlights the first new line after any forward movement  command  larger
              than one line.

       -xn,... or --tabs=n,...
              Sets  tab  stops.   If  only one n is specified, tab stops are set at multiples of n.  If multiple
              values separated by commas are specified, tab stops are set at those positions, and then  continue
              with  the same spacing as the last two.  For example, -x9,17 will set tabs at positions 9, 17, 25,
              33, etc.  The default for n is 8.

       -X or --no-init
              Disables sending the termcap initialization and deinitialization strings to the terminal.  This is
              sometimes  desirable  if the deinitialization string does something unnecessary, like clearing the
              screen.

       -yn or --max-forw-scroll=n
              Specifies a maximum number of lines to scroll forward.  If it is necessary to scroll forward  more
              than  n  lines,  the screen is repainted instead.  The -c or -C option may be used to repaint from
              the top of the screen if desired.  By default, any forward movement causes scrolling.

       -[z]n or --window=n
              Changes the default scrolling window size to n lines.  The default is one screenful.  The z and  w
              commands  can  also  be  used to change the window size.  The "z" may be omitted for compatibility
              with some versions of more.  If the number n is negative, it  indicates  n  lines  less  than  the
              current screen size.  For example, if the screen is 24 lines, -z-4 sets the scrolling window to 20
              lines.  If the screen is resized to 40 lines, the scrolling window  automatically  changes  to  36
              lines.

       -"cc or --quotes=cc
              Changes  the  filename  quoting character.  This may be necessary if you are trying to name a file
              which contains both spaces and quote characters.  Followed by a single character, this changes the
              quote character to that character.  Filenames containing a space should then be surrounded by that
              character rather than by double quotes.  Followed by two characters, changes the open quote to the
              first character, and the close quote to the second character.  Filenames containing a space should
              then be preceded by the open quote character and followed by the close quote character.  Note that
              even  after  the quote characters are changed, this option remains -" (a dash followed by a double
              quote).

       -~ or --tilde
              Normally lines after end of file are displayed as a single tilde (~).  This  option  causes  lines
              after end of file to be displayed as blank lines.

       -# or --shift
              Specifies  the  default number of positions to scroll horizontally in the RIGHTARROW and LEFTARROW
              commands.  If the number specified is zero, it sets the default number of positions to one half of
              the  screen  width.   Alternately,  the  number may be specified as a fraction of the width of the
              screen, starting with a decimal point: .5 is half of the screen width, .3 is three tenths  of  the
              screen  width,  and  so on.  If the number is specified as a fraction, the actual number of scroll
              positions is recalculated if the terminal window is resized, so that the actual scroll remains  at
              the specified fraction of the screen width.

       --follow-name
              Normally,  if  the  input  file  is renamed while an F command is executing, less will continue to
              display the contents of the original file despite its name change.  If --follow-name is specified,
              during  an  F  command  less  will periodically attempt to reopen the file by name.  If the reopen
              succeeds and the file is a different file from the original (which means that a new file has  been
              created  with the same name as the original (now renamed) file), less will display the contents of
              that new file.

       --no-keypad
              Disables sending the keypad initialization and deinitialization strings to the terminal.  This  is
              sometimes useful if the keypad strings make the numeric keypad behave in an undesirable manner.

       --use-backslash
              This  option  changes  the  interpretations  of  options  which follow this one.  After the --use-
              backslash option, any backslash in an option string is removed  and  the  following  character  is
              taken literally.  This allows a dollar sign to be included in option strings.

       --     A  command  line argument of "--" marks the end of option arguments.  Any arguments following this
              are interpreted as filenames.  This can be useful when viewing a file whose name begins with a "-"
              or "+".

       +      If  a  command  line  option begins with +, the remainder of that option is taken to be an initial
              command to less.  For example, +G tells less to start at the end  of  the  file  rather  than  the
              beginning, and +/xyz tells it to start at the first occurrence of "xyz" in the file.  As a special
              case, +<number> acts like +<number>g; that is, it starts the display at the specified line  number
              (however,  see the caveat under the "g" command above).  If the option starts with ++, the initial
              command applies to every file being viewed, not just the  first  one.   The  +  command  described
              previously may also be used to set (or change) an initial command for every file.

LINE EDITING

       When  entering  command  line at the bottom of the screen (for example, a filename for the :e command, or
       the pattern for a search command), certain keys can  be  used  to  manipulate  the  command  line.   Most
       commands have an alternate form in [ brackets ] which can be used if a key does not exist on a particular
       keyboard.  (Note that the forms beginning with ESC do not work in some MS-DOS and Windows systems because
       ESC  is  the  line  erase character.)  Any of these special keys may be entered literally by preceding it
       with the "literal" character, either ^V or ^A.  A backslash itself  may  also  be  entered  literally  by
       entering two backslashes.

       LEFTARROW [ ESC-h ]
              Move the cursor one space to the left.

       RIGHTARROW [ ESC-l ]
              Move the cursor one space to the right.

       ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
              (That is, CONTROL and LEFTARROW simultaneously.)  Move the cursor one word to the left.

       ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
              (That is, CONTROL and RIGHTARROW simultaneously.)  Move the cursor one word to the right.

       HOME [ ESC-0 ]
              Move the cursor to the beginning of the line.

       END [ ESC-$ ]
              Move the cursor to the end of the line.

       BACKSPACE
              Delete  the  character  to  the  left  of the cursor, or cancel the command if the command line is
              empty.

       DELETE or [ ESC-x ]
              Delete the character under the cursor.

       ^BACKSPACE [ ESC-BACKSPACE ]
              (That is, CONTROL and BACKSPACE simultaneously.)  Delete the word to the left of the cursor.

       ^DELETE [ ESC-X or ESC-DELETE ]
              (That is, CONTROL and DELETE simultaneously.)  Delete the word under the cursor.

       UPARROW [ ESC-k ]
              Retrieve the previous command line.  If you first enter some text and then press UPARROW, it  will
              retrieve the previous command which begins with that text.

       DOWNARROW [ ESC-j ]
              Retrieve  the  next  command line.  If you first enter some text and then press DOWNARROW, it will
              retrieve the next command which begins with that text.

       TAB    Complete the partial filename to the left of the cursor.  If it matches more  than  one  filename,
              the  first  match  is  entered  into  the  command  line.  Repeated TABs will cycle thru the other
              matching filenames.  If the completed filename is a directory, a "/" is appended to the  filename.
              (On  MS-DOS  systems,  a  "\" is appended.)  The environment variable LESSSEPARATOR can be used to
              specify a different character to append to a directory name.

       BACKTAB [ ESC-TAB ]
              Like, TAB, but cycles in the reverse direction thru the matching filenames.

       ^L     Complete the partial filename to the left of the cursor.  If it matches more  than  one  filename,
              all matches are entered into the command line (if they fit).

       ^U (Unix and OS/2) or ESC (MS-DOS)
              Delete  the  entire command line, or cancel the command if the command line is empty.  If you have
              changed your line-kill character in Unix to something  other  than  ^U,  that  character  is  used
              instead of ^U.

       ^G     Delete the entire command line and return to the main prompt.

KEY BINDINGS

       You  may  define  your own less commands by using the program lesskey (1) to create a lesskey file.  This
       file specifies a set of command keys and an action associated with each key.  You may also use lesskey to
       change  the  line-editing  keys (see LINE EDITING), and to set environment variables.  If the environment
       variable LESSKEY is set, less uses that as the name of the lesskey file.   Otherwise,  less  looks  in  a
       standard place for the lesskey file: On Unix systems, less looks for a lesskey file called "$HOME/.less".
       On MS-DOS and Windows systems, less looks for a lesskey file called "$HOME/_less", and if it is not found
       there,  then  looks  for a lesskey file called "_less" in any directory specified in the PATH environment
       variable.  On OS/2 systems, less looks for a lesskey file called  "$HOME/less.ini",  and  if  it  is  not
       found, then looks for a lesskey file called "less.ini" in any directory specified in the INIT environment
       variable, and if it not found there, then looks for a lesskey file called  "less.ini"  in  any  directory
       specified in the PATH environment variable.  See the lesskey manual page for more details.

       A  system-wide  lesskey  file  may also be set up to provide key bindings.  If a key is defined in both a
       local lesskey file and in the system-wide file, key bindings in the local file take precedence over those
       in  the  system-wide file.  If the environment variable LESSKEY_SYSTEM is set, less uses that as the name
       of the system-wide lesskey file.  Otherwise, less looks in a standard place for the  system-wide  lesskey
       file:  On  Unix  systems,  the system-wide lesskey file is /usr/local/etc/sysless.  (However, if less was
       built with a different sysconf directory than /usr/local/etc, that directory is where the sysless file is
       found.)   On  MS-DOS  and Windows systems, the system-wide lesskey file is c:\_sysless.  On OS/2 systems,
       the system-wide lesskey file is c:\sysless.ini.

INPUT PREPROCESSOR

       You may define an "input preprocessor" for less.  Before less opens a file, it  first  gives  your  input
       preprocessor a chance to modify the way the contents of the file are displayed.  An input preprocessor is
       simply an executable program (or shell script), which writes the contents of  the  file  to  a  different
       file,  called  the replacement file.  The contents of the replacement file are then displayed in place of
       the contents of the original file.  However, it will appear to the  user  as  if  the  original  file  is
       opened; that is, less will display the original filename as the name of the current file.

       An  input preprocessor receives one command line argument, the original filename, as entered by the user.
       It should create the replacement file, and when finished, print the name of the replacement file  to  its
       standard  output.   If  the  input  preprocessor  does  not  output a replacement filename, less uses the
       original file, as normal.  The input preprocessor is not called when viewing standard input.  To  set  up
       an  input  preprocessor,  set  the LESSOPEN environment variable to a command line which will invoke your
       input preprocessor.  This command line should include one occurrence of the string "%s",  which  will  be
       replaced by the filename when the input preprocessor command is invoked.

       When  less  closes  a  file  opened  in  such  a  way,  it  will  call  another program, called the input
       postprocessor, which may perform any desired clean-up action  (such  as  deleting  the  replacement  file
       created by LESSOPEN).  This program receives two command line arguments, the original filename as entered
       by the user, and the name of the replacement file.  To set up an input postprocessor, set  the  LESSCLOSE
       environment  variable  to  a command line which will invoke your input postprocessor.  It may include two
       occurrences of the string "%s"; the first is replaced with the original name of the file and  the  second
       with the name of the replacement file, which was output by LESSOPEN.

       For  example,  on many Unix systems, these two scripts will allow you to keep files in compressed format,
       but still let less view them directly:

       lessopen.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -
                 if [ -s /tmp/less.$$ ]; then
                      echo /tmp/less.$$
                 else
                      rm -f /tmp/less.$$
                 fi
                 ;;
            esac

       lessclose.sh:
            #! /bin/sh
            rm $2

       To use these scripts, put them both where they can be executed  and  set  LESSOPEN="lessopen.sh %s",  and
       LESSCLOSE="lessclose.sh %s %s".   More  complex  LESSOPEN  and LESSCLOSE scripts may be written to accept
       other types of compressed files, and so on.

       It is also possible to set up an input preprocessor to pipe the file data directly to less,  rather  than
       putting  the  data  into  a  replacement file.  This avoids the need to decompress the entire file before
       starting to view it.  An input preprocessor that works this way is called an input pipe.  An input  pipe,
       instead  of  writing the name of a replacement file on its standard output, writes the entire contents of
       the replacement file on its standard output.  If the input pipe does not  write  any  characters  on  its
       standard output, then there is no replacement file and less uses the original file, as normal.  To use an
       input pipe, make the first character in the LESSOPEN environment variable a vertical bar (|)  to  signify
       that the input preprocessor is an input pipe.

       For example, on many Unix systems, this script will work like the previous example scripts:

       lesspipe.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -c $1  2>/dev/null
            *)   exit 1
                 ;;
            esac
            exit $?

       To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh %s".

       Note  that  a  preprocessor cannot output an empty file, since that is interpreted as meaning there is no
       replacement, and the original file is used.  To avoid this, if LESSOPEN starts with  two  vertical  bars,
       the  exit  status of the script becomes meaningful.  If the exit status is zero, the output is considered
       to be replacement text, even if it empty.  If the exit status is nonzero, any output is ignored  and  the
       original  file  is  used.  For compatibility with previous versions of less, if LESSOPEN starts with only
       one vertical bar, the exit status of the preprocessor is ignored.

       When an input pipe is used, a LESSCLOSE postprocessor can be used, but it is usually not necessary  since
       there  is  no  replacement  file  to  clean  up.   In  this case, the replacement file name passed to the
       LESSCLOSE postprocessor is "-".

       For compatibility with previous versions of less, the input preprocessor or pipe is not used if  less  is
       viewing  standard  input.   However,  if  the  first  character  of  LESSOPEN  is  a  dash (-), the input
       preprocessor is used on standard input as well as other files.  In this case, the dash is not  considered
       to  be  part  of  the preprocessor command.  If standard input is being viewed, the input preprocessor is
       passed a file name consisting of a single dash.  Similarly, if the first two characters of  LESSOPEN  are
       vertical  bar  and  dash  (|-)  or two vertical bars and a dash (||-), the input pipe is used on standard
       input as well as other files.  Again, in this case the dash is not considered to be  part  of  the  input
       pipe command.

NATIONAL CHARACTER SETS

       There are three types of characters in the input file:

       normal characters
              can be displayed directly to the screen.

       control characters
              should  not  be  displayed  directly, but are expected to be found in ordinary text files (such as
              backspace and tab).

       binary characters
              should not be displayed directly and are not expected to be found in text files.

       A "character set" is simply a description of which characters are to be considered normal,  control,  and
       binary.  The LESSCHARSET environment variable may be used to select a character set.  Possible values for
       LESSCHARSET are:

       ascii  BS, TAB, NL, CR, and formfeed are control characters, all chars with values between 32 and 126 are
              normal, and all others are binary.

       iso8859
              Selects  an  ISO 8859 character set.  This is the same as ASCII, except characters between 160 and
              255 are treated as normal characters.

       latin1 Same as iso8859.

       latin9 Same as iso8859.

       dos    Selects a character set appropriate for MS-DOS.

       ebcdic Selects an EBCDIC character set.

       IBM-1047
              Selects an EBCDIC character set used by OS/390 Unix Services.  This  is  the  EBCDIC  analogue  of
              latin1.   You get similar results by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
              environment.

       koi8-r Selects a Russian character set.

       next   Selects a character set appropriate for NeXT computers.

       utf-8  Selects the UTF-8 encoding of the ISO 10646 character set.  UTF-8 is special in that  it  supports
              multi-byte  characters  in  the input file.  It is the only character set that supports multi-byte
              characters.

       windows
              Selects a character set appropriate for Microsoft Windows (cp 1251).

       In rare cases, it may be desired to tailor less to use a character set other than the ones  definable  by
       LESSCHARSET.   In  this case, the environment variable LESSCHARDEF can be used to define a character set.
       It should be set to a string where each character in the string represents one character in the character
       set.   The  character "." is used for a normal character, "c" for control, and "b" for binary.  A decimal
       number may be used for repetition.  For example, "bccc4b." would mean character 0 is binary, 1, 2  and  3
       are  control,  4,  5, 6 and 7 are binary, and 8 is normal.  All characters after the last are taken to be
       the same as the last, so characters 9 through 255 would be normal.  (This is an  example,  and  does  not
       necessarily represent any real character set.)

       This  table  shows  the  value  of  LESSCHARDEF  which  is  equivalent to each of the possible values for
       LESSCHARSET:

            ascii     8bcccbcc18b95.b
            dos       8bcccbcc12bc5b95.b.
            ebcdic    5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
                      9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
            IBM-1047  4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
                      191.b
            iso8859   8bcccbcc18b95.33b.
            koi8-r    8bcccbcc18b95.b128.
            latin1    8bcccbcc18b95.33b.
            next      8bcccbcc18b95.bb125.bb

       If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings "UTF-8", "UTF8", "utf-8" or  "utf8"
       is found in the LC_ALL, LC_CTYPE or LANG environment variables, then the default character set is utf-8.

       If that string is not found, but your system supports the setlocale interface, less will use setlocale to
       determine the character set.  setlocale is  controlled  by  setting  the  LANG  or  LC_CTYPE  environment
       variables.

       Finally, if the setlocale interface is also not available, the default character set is latin1.

       Control  and  binary  characters  are  displayed  in  standout  (reverse  video).  Each such character is
       displayed in caret notation if possible (e.g.  ^A  for  control-A).   Caret  notation  is  used  only  if
       inverting the 0100 bit results in a normal printable character.  Otherwise, the character is displayed as
       a hex number in angle brackets.  This format  can  be  changed  by  setting  the  LESSBINFMT  environment
       variable.   LESSBINFMT  may  begin  with a "*" and one character to select the display attribute: "*k" is
       blinking, "*d" is bold, "*u" is underlined, "*s" is standout, and "*n" is normal.  If LESSBINFMT does not
       begin with a "*", normal attribute is assumed.  The remainder of LESSBINFMT is a string which may include
       one printf-style escape sequence (a % followed by x, X, o, d,  etc.).   For  example,  if  LESSBINFMT  is
       "*u[%x]",  binary characters are displayed in underlined hexadecimal surrounded by brackets.  The default
       if no LESSBINFMT is specified is  "*s<%02X>".   Warning:  the  result  of  expanding  the  character  via
       LESSBINFMT must be less than 31 characters.

       When  the character set is utf-8, the LESSUTFBINFMT environment variable acts similarly to LESSBINFMT but
       it applies to Unicode code points that were successfully decoded but are unsuitable  for  display  (e.g.,
       unassigned code points).  Its default value is "<U+%04lX>".  Note that LESSUTFBINFMT and LESSBINFMT share
       their display attribute setting ("*x") so specifying one will affect both; LESSUTFBINFMT  is  read  after
       LESSBINFMT  so  its setting, if any, will have priority.  Problematic octets in a UTF-8 file (octets of a
       truncated sequence, octets of a complete but  non-shortest  form  sequence,  illegal  octets,  and  stray
       trailing  octets)  are  displayed individually using LESSBINFMT so as to facilitate diagnostic of how the
       UTF-8 file is ill-formed.

PROMPTS

       The -P option allows you to tailor the prompt to your preference.  The string  given  to  the  -P  option
       replaces  the  specified prompt string.  Certain characters in the string are interpreted specially.  The
       prompt mechanism is rather complicated to provide flexibility, but the ordinary user need not  understand
       the details of constructing personalized prompt strings.

       A percent sign followed by a single character is expanded according to what the following character is:

       %bX    Replaced  by the byte offset into the current input file.  The b is followed by a single character
              (shown as X above) which specifies the line whose byte offset is to be used.  If the character  is
              a "t", the byte offset of the top line in the display is used, an "m" means use the middle line, a
              "b" means use the bottom line, a "B" means use the line just after the  bottom  line,  and  a  "j"
              means use the "target" line, as specified by the -j option.

       %B     Replaced by the size of the current input file.

       %c     Replaced by the column number of the text appearing in the first column of the screen.

       %dX    Replaced by the page number of a line in the input file.  The line to be used is determined by the
              X, as with the %b option.

       %D     Replaced by the number of pages in the input file, or equivalently, the page number  of  the  last
              line in the input file.

       %E     Replaced  by  the  name  of  the  editor  (from  the  VISUAL  environment  variable, or the EDITOR
              environment variable if VISUAL is not defined).  See the discussion of the LESSEDIT feature below.

       %f     Replaced by the name of the current input file.

       %F     Replaced by the last component of the name of the current input file.

       %i     Replaced by the index of the current file in the list of input files.

       %lX    Replaced by the line number of a line in the input file.  The line to be used is determined by the
              X, as with the %b option.

       %L     Replaced by the line number of the last line in the input file.

       %m     Replaced by the total number of input files.

       %pX    Replaced  by  the  percent  into  the current input file, based on byte offsets.  The line used is
              determined by the X as with the %b option.

       %PX    Replaced by the percent into the current input file, based on line  numbers.   The  line  used  is
              determined by the X as with the %b option.

       %s     Same as %B.

       %t     Causes  any  trailing spaces to be removed.  Usually used at the end of the string, but may appear
              anywhere.

       %x     Replaced by the name of the next input file in the list.

       If any item is unknown (for example, the file size if input is  a  pipe),  a  question  mark  is  printed
       instead.

       The format of the prompt string can be changed depending on certain conditions.  A question mark followed
       by a single character acts like an "IF": depending on the following character, a condition is  evaluated.
       If  the  condition  is  true, any characters following the question mark and condition character, up to a
       period, are included in the prompt.  If the condition is false, such  characters  are  not  included.   A
       colon  appearing  between  the  question  mark  and  the  period  can be used to establish an "ELSE": any
       characters between the colon and the period are included in the string if and only if the IF condition is
       false.  Condition characters (which follow a question mark) may be:

       ?a     True if any characters have been included in the prompt so far.

       ?bX    True if the byte offset of the specified line is known.

       ?B     True if the size of current input file is known.

       ?c     True if the text is horizontally shifted (%c is not zero).

       ?dX    True if the page number of the specified line is known.

       ?e     True if at end-of-file.

       ?f     True if there is an input filename (that is, if input is not a pipe).

       ?lX    True if the line number of the specified line is known.

       ?L     True if the line number of the last line in the file is known.

       ?m     True if there is more than one input file.

       ?n     True if this is the first prompt in a new input file.

       ?pX    True  if  the percent into the current input file, based on byte offsets, of the specified line is
              known.

       ?PX    True if the percent into the current input file, based on line numbers, of the specified  line  is
              known.

       ?s     Same as "?B".

       ?x     True if there is a next input file (that is, if the current input file is not the last one).

       Any  characters other than the special ones (question mark, colon, period, percent, and backslash) become
       literally part of the prompt.  Any of the special characters may be included in the prompt  literally  by
       preceding it with a backslash.

       Some examples:

       ?f%f:Standard input.

       This prompt prints the filename, if known; otherwise the string "Standard input".

       ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...

       This  prompt  would print the filename, if known.  The filename is followed by the line number, if known,
       otherwise the percent if known, otherwise the byte offset  if  known.   Otherwise,  a  dash  is  printed.
       Notice how each question mark has a matching period, and how the % after the %pt is included literally by
       escaping it with a backslash.

       ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t

       This prints the filename if this is the first prompt in a file, followed by the "file N of N" message  if
       there  is  more  than  one  input  file.   Then,  if we are at end-of-file, the string "(END)" is printed
       followed by the name of the next file, if there is one.  Finally,  any  trailing  spaces  are  truncated.
       This  is  the  default prompt.  For reference, here are the defaults for the other two prompts (-m and -M
       respectively).  Each is broken into two lines here for readability only.

       ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.:
            ?pB%pB\%:byte %bB?s/%s...%t

       ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. :
            byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t

       And here is the default message produced by the = command:

       ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. .
            byte %bB?s/%s. ?e(END) :?pB%pB\%..%t

       The prompt expansion features are also used for another purpose: if an environment variable  LESSEDIT  is
       defined,  it is used as the command to be executed when the v command is invoked.  The LESSEDIT string is
       expanded in the same way as the prompt strings.  The default value for LESSEDIT is:

            %E ?lm+%lm. %f

       Note that this expands to the editor name, followed by a + and the line  number,  followed  by  the  file
       name.   If  your  editor does not accept the "+linenumber" syntax, or has other differences in invocation
       syntax, the LESSEDIT variable can be changed to modify this default.

SECURITY

       When the environment variable LESSSECURE is set to 1, less runs in a "secure"  mode.   This  means  these
       features are disabled:

              !      the shell command

              |      the pipe command

              :e     the examine command.

              v      the editing command

              s  -o  log files

              -k     use of lesskey files

              -t     use of tags files

                     metacharacters in filenames, such as *

                     filename completion (TAB, ^L)

       Less can also be compiled to be permanently in "secure" mode.

COMPATIBILITY WITH MORE

       If  the environment variable LESS_IS_MORE is set to 1, or if the program is invoked via a file link named
       "more", less behaves (mostly) in conformance with the POSIX "more" command specification.  In this  mode,
       less behaves differently in these ways:

       The -e option works differently.  If the -e option is not set, less behaves as if the -E option were set.
       If the -e option is set, less behaves as if the -e and -F options were set.

       The -m option works differently.  If the -m option is not set, the medium  prompt  is  used,  and  it  is
       prefixed with the string "--More--".  If the -m option is set, the short prompt is used.

       The -n option acts like the -z option.  The normal behavior of the -n option is unavailable in this mode.

       The parameter to the -p option is taken to be a less command rather than a search pattern.

       The LESS environment variable is ignored, and the MORE environment variable is used in its place.

ENVIRONMENT VARIABLES

       Environment  variables  may  be  specified either in the system environment as usual, or in a lesskey (1)
       file.  If environment variables are defined in more than one place, variables defined in a local  lesskey
       file  take  precedence  over  variables  defined  in  the  system environment, which take precedence over
       variables defined in the system-wide lesskey file.

       COLUMNS
              Sets the number of columns on the screen.  Takes precedence over the number of  columns  specified
              by  the TERM variable.  (But if you have a windowing system which supports TIOCGWINSZ or WIOCGETD,
              the window system's idea  of  the  screen  size  takes  precedence  over  the  LINES  and  COLUMNS
              environment variables.)

       EDITOR The name of the editor (used for the v command).

       HOME   Name of the user's home directory (used to find a lesskey file on Unix and OS/2 systems).

       HOMEDRIVE, HOMEPATH
              Concatenation  of  the HOMEDRIVE and HOMEPATH environment variables is the name of the user's home
              directory if the HOME variable is not set (only in the Windows version).

       INIT   Name of the user's init directory (used to find a lesskey file on OS/2 systems).

       LANG   Language for determining the character set.

       LC_CTYPE
              Language for determining the character set.

       LESS   Options which are passed to less automatically.

       LESSANSIENDCHARS
              Characters which may end an ANSI color escape sequence (default "m").

       LESSANSIMIDCHARS
              Characters which may appear between the ESC character and the  end  character  in  an  ANSI  color
              escape sequence (default "0123456789;[?!"'#%()*+ ".

       LESSBINFMT
              Format for displaying non-printable, non-control characters.

       LESSCHARDEF
              Defines a character set.

       LESSCHARSET
              Selects a predefined character set.

       LESSCLOSE
              Command line to invoke the (optional) input-postprocessor.

       LESSECHO
              Name  of  the  lessecho  program  (default  "lessecho").  The lessecho program is needed to expand
              metacharacters, such as * and ?, in filenames on Unix systems.

       LESSEDIT
              Editor prototype string (used for the v command).  See discussion under PROMPTS.

       LESSGLOBALTAGS
              Name of the command used by the -t option to find global tags.  Normally should be set to "global"
              if your system has the global (1) command.  If not set, global tags are not used.

       LESSHISTFILE
              Name  of  the history file used to remember search commands and shell commands between invocations
              of less.   If  set  to  "-"  or  "/dev/null",  a  history  file  is  not  used.   The  default  is
              "$HOME/.lesshst"   on   Unix   systems,   "$HOME/_lesshst"   on   DOS   and  Windows  systems,  or
              "$HOME/lesshst.ini" or "$INIT/lesshst.ini" on OS/2 systems.

       LESSHISTSIZE
              The maximum number of commands to save in the history file.  The default is 100.

       LESSKEY
              Name of the default lesskey(1) file.

       LESSKEY_SYSTEM
              Name of the default system-wide lesskey(1) file.

       LESSMETACHARS
              List of characters which are considered "metacharacters" by the shell.

       LESSMETAESCAPE
              Prefix which less will add before  each  metacharacter  in  a  command  sent  to  the  shell.   If
              LESSMETAESCAPE  is  an  empty string, commands containing metacharacters will not be passed to the
              shell.

       LESSOPEN
              Command line to invoke the (optional) input-preprocessor.

       LESSSECURE
              Runs less in "secure" mode.  See discussion under SECURITY.

       LESSSEPARATOR
              String to be appended to a directory name in filename completion.

       LESSUTFBINFMT
              Format for displaying non-printable Unicode code points.

       LESS_IS_MORE
              Emulate the more (1) command.

       LINES  Sets the number of lines on the screen.  Takes precedence over the number of  lines  specified  by
              the TERM variable.  (But if you have a windowing system which supports TIOCGWINSZ or WIOCGETD, the
              window system's idea of the screen size takes precedence over the LINES  and  COLUMNS  environment
              variables.)

       MORE   Options which are passed to less automatically when running in more compatible mode.

       PATH   User's search path (used to find a lesskey file on MS-DOS and OS/2 systems).

       SHELL  The shell used to execute the ! command, as well as to expand filenames.

       TERM   The type of terminal on which less is being run.

       VISUAL The name of the editor (used for the v command).

SEE ALSO

       lesskey(1)

       Copyright (C) 1984-2012  Mark Nudelman

       less is part of the GNU project and is free software.  You can redistribute it and/or modify it under the
       terms of either (1) the GNU General Public License as published by the Free Software Foundation;  or  (2)
       the   Less  License.   See  the  file  README  in  the  less  distribution  for  more  details  regarding
       redistribution.  You should have received a copy of the GNU General Public License along with the  source
       for  less;  see  the file COPYING.  If not, write to the Free Software Foundation, 59 Temple Place, Suite
       330, Boston, MA  02111-1307, USA.  You should also have received a copy of the Less License; see the file
       LICENSE.

       less  is  distributed  in  the  hope  that  it will be useful, but WITHOUT ANY WARRANTY; without even the
       implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.   See  the  GNU  General  Public
       License for more details.

AUTHOR

       Mark Nudelman
       Send bug reports or comments to <bug-less@gnu.org>
       See http://www.greenwoodsoftware.com/less/bugs.html for the latest list of known bugs in less.
       For more information, see the less homepage at
       http://www.greenwoodsoftware.com/less.

                                            Version 458: 04 Apr 2013                                     LESS(1)