Provided by: pdksh_5.2.14-26_i386 bug

NAME

       pdksh - Public domain Korn shell

SYNOPSIS

       pdksh [+-abCefhikmnprsuvxX] [+-o option] [ [ -c command-string
       [command-name] | -s | file ] [argument ...] ]

DESCRIPTION

       ksh is a command interpreter that is intended for both interactive  and
       shell  script  use.   Its  command  language is a superset of the sh(1)
       shell language.

   Shell Startup
       The following options can be specified only on the command line:

       -c command-string
              the shell executes the command(s) contained in command-string

       -i     interactive mode -- see below

       -l     login shell -- see below interactive mode -- see below

       -s     the shell reads commands from  standard  input;  all  non-option
              arguments are positional parameters

       -r     restricted mode -- see below

       In  addition  to  the  above, the options described in the set built-in
       command can also be used on the command line.

       If neither the -c nor the -s options  are  specified,  the  first  non-
       option  argument  specifies the name of a file the shell reads commands
       from; if there are no non-option arguments, the  shell  reads  commands
       from  standard input.  The name of the shell (i.e., the contents of the
       $0) parameter is determined as follows: if the -c option  is  used  and
       there is a non-option argument, it is used as the name; if commands are
       being read from a file, the file is used as  the  name;  otherwise  the
       name the shell was called with (i.e., argv[0]) is used.

       A  shell  is  interactive  if the -i option is used or if both standard
       input and standard error are attached to a tty.  An  interactive  shell
       has  job control enabled (if available), ignores the INT, QUIT and TERM
       signals, and prints prompts before  reading  input  (see  PS1  and  PS2
       parameters).   For non-interactive shells, the trackall option is on by
       default (see set command below).

       A shell is restricted if the  -r  option  is  used  or  if  either  the
       basename  of  the name the shell is invoked with or the SHELL parameter
       match the pattern *r*sh (e.g., rsh, rksh, rpdksh, etc.).  The following
       restrictions come into effect after the shell processes any profile and
       $ENV files:
         o    the cd command is disabled
         o    the SHELL, ENV and PATH parameters can't be changed
         o    command names can't be specified with absolute or relative paths
         o    the -p option of the command built-in can't be used
         o    redirections that create files can't be used (i.e., >,  >|,  >>,
              <>)

       A  shell  is privileged if the -p option is used or if the real user-id
       or group-id does not match  the  effective  user-id  or  group-id  (see
       getuid(2),   getgid(2)).    A   privileged   shell   does  not  process
       $HOME/.profile nor the ENV parameter  (see  below),  instead  the  file
       /etc/suid_profile  is processed.  Clearing the privileged option causes
       the shell to set its effective user-id (group-id) to its  real  user-id
       (group-id).

       If  the  basename  of the name the shell is called with (i.e., argv[0])
       starts with - or if the -l option is used, the shell is assumed to be a
       login   shell  and  the  shell  reads  and  executes  the  contents  of
       /etc/profile and $HOME/.profile if they exist and are readable.

       If the ENV parameter is set when the shell starts (or, in the  case  of
       login shells, after any profiles are processed), its value is subjected
       to parameter,  command,  arithmetic  and  tilde  substitution  and  the
       resulting  file (if any) is read and executed.  If ENV parameter is not
       set (and not null) and pdksh was compiled with  the  DEFAULT_ENV  macro
       defined,  the  file  named  in  that macro is included (after the above
       mentioned substitutions have been performed).

       The exit status of the shell is 127 if the command  file  specified  on
       the  command  line  could  not be opened, or non-zero if a fatal syntax
       error occurred during the execution of a script.   In  the  absence  of
       fatal  errors, the exit status is that of the last command executed, or
       zero, if no command is executed.

   Command Syntax
       The shell begins parsing its input by breaking it into  words.   Words,
       which  are  sequences  of  characters, are delimited by unquoted white-
       space characters (space, tab and newline) or meta-characters (<, >,  |,
       ;,  &,  (  and  )).   Aside  from delimiting words, spaces and tabs are
       ignored, while newlines usually delimit commands.  The  meta-characters
       are  used  in building the following tokens: <, <&, <<, >, >&, >>, etc.
       are used to specify redirections (see Input/Output Redirection  below);
       |  is  used to create pipelines; |& is used to create co-processes (see
       Co-Processes below); ; is used to  separate  commands;  &  is  used  to
       create   asynchronous   pipelines;  &&  and  ||  are  used  to  specify
       conditional execution; ;; is used in case statements; (( .. )) are used
       in  arithmetic  expressions;  and  lastly,  (  ..  ) are used to create
       subshells.

       White-space  and  meta-characters  can  be  quoted  individually  using
       backslash  (\),  or  in  groups  using double (") or single (') quotes.
       Note that the following characters are also treated  specially  by  the
       shell  and must be quoted if they are to represent themselves: \, ", ',
       #, $, `, ~, {, }, *, ? and [.  The first three of these are  the  above
       mentioned  quoting  characters  (see  Quoting below); #, if used at the
       beginning of a word, introduces a comment -- everything after the #  up
       to  the  nearest  newline is ignored; $ is used to introduce parameter,
       command  and  arithmetic  substitutions  (see  Substitution  below);  `
       introduces  an old-style command substitution (see Substitution below);
       ~ begins a directory expansion (see Tilde Expansion  below);  {  and  }
       delimit  csh(1)  style  alternations  (see Brace Expansion below); and,
       finally, *, ? and [ are used in file name  generation  (see  File  Name
       Patterns below).

       As  words  and  tokens  are parsed, the shell builds commands, of which
       there are two basic types: simple-commands, typically programs that are
       executed,  and  compound-commands,  such  as  for  and  if  statements,
       grouping constructs and function definitions.

       A simple-command consists of some combination of parameter  assignments
       (see  Parameters  below),  input/output  redirections (see Input/Output
       Redirections below), and command words; the only  restriction  is  that
       parameter  assignments  come  before  any  command  words.  The command
       words, if any, define the command  that  is  to  be  executed  and  its
       arguments.   The command may be a shell built-in command, a function or
       an external command, i.e., a separate executable file that  is  located
       using  the PATH parameter (see Command Execution below).  Note that all
       command constructs have an exit status: for external commands, this  is
       related  to the status returned by wait(2) (if the command could not be
       found, the exit status is 127, if it could not be  executed,  the  exit
       status  is  126); the exit status of other command constructs (built-in
       commands, functions, compound-commands, pipelines, lists, etc.) are all
       well  defined  and are described where the construct is described.  The
       exit status of a command consisting only of  parameter  assignments  is
       that  of  the  last command substitution performed during the parameter
       assignment or zero if there were no command substitutions.

       Commands can be chained together using the | token to  form  pipelines,
       in which the standard output of each command but the last is piped (see
       pipe(2)) to the standard input of  the  following  command.   The  exit
       status  of  a  pipeline is that of its last command.  A pipeline may be
       prefixed by the ! reserved word which causes the  exit  status  of  the
       pipeline to be logically complemented: if the original status was 0 the
       complemented status will be 1, and if the original status  was  not  0,
       then the complemented status will be 0.

       Lists  of commands can be created by separating pipelines by any of the
       following tokens: &&,  ||,  &,  |&  and  ;.   The  first  two  are  for
       conditional  execution:  cmd1  &&  cmd2  executes cmd2 only if the exit
       status of cmd1 is zero; || is the opposite -- cmd2 is executed only  if
       the  exit  status of cmd1 is non-zero.  && and || have equal precedence
       which is higher than that of  &,  |&  and  ;,  which  also  have  equal
       precedence.   The  &  token causes the preceding command to be executed
       asynchronously, that is, the shell starts the  command,  but  does  not
       wait  for  it  to  complete (the shell does keep track of the status of
       asynchronous commands -- see Job Control below).  When an  asynchronous
       command  is  started  when  job  control  is  disabled  (i.e.,  in most
       scripts), the command is started with signals INT and QUIT ignored  and
       with  input  redirected from /dev/null (however, redirections specified
       in the asynchronous command have precedence).  The |& operator starts a
       co-process  which  is  special  kind  of  asynchronous process (see Co-
       Processes below).  Note that a  command  must  follow  the  &&  and  ||
       operators,  while  a  command  need  not  follow &, |& and ;.  The exit
       status of a list is  that  of  the  last  command  executed,  with  the
       exception of asynchronous lists, for which the exit status is 0.

       Compound  commands  are  created  using the following reserved words --
       these words are only recognized if they are unquoted and  if  they  are
       used  as  the  first word of a command (i.e., they can't be preceded by
       parameter assignments or redirections):

                         case   else   function   then    !
                         do     esac   if         time    [[
                         done   fi     in         until   {
                         elif   for    select     while   }
       Note: Some shells (but not this one) execute control structure commands
       in  a  subshell  when  one  or  more  of  their  file  descriptors  are
       redirected, so any environment changes inside them  may  fail.   To  be
       portable,  the  exec  statement should be used instead to redirect file
       descriptors before the control structure.

       In the following compound command descriptions, command lists  (denoted
       as  list)  that  are  followed  by reserved words must end with a semi-
       colon, a newline or  a  (syntactically  correct)  reserved  word.   For
       example,
              { echo foo; echo bar; }
              { echo foo; echo bar<newline>}
              { { echo foo; echo bar; } }
       are all valid, but
              { echo foo; echo bar }
       is not.

       ( list )
              Execute  list  in  a subshell.  There is no implicit way to pass
              environment changes from a subshell back to its parent.

       { list }
              Compound construct; list is executed, but  not  in  a  subshell.
              Note that { and } are reserved words, not meta-characters.

       case word in [ [(] pattern [| pattern] ... ) list ;; ] ... esac
              The  case statement attempts to match word against the specified
              patterns;  the  list  associated  with  the  first  successfully
              matched  pattern  is executed.  Patterns used in case statements
              are the same as those used for file name  patterns  except  that
              the  restrictions  regarding . and / are dropped.  Note that any
              unquoted space before and after a pattern is stripped; any space
              with  a  pattern must be quoted.  Both the word and the patterns
              are subject to parameter, command, and  arithmetic  substitution
              as well as tilde substitution.  For historical reasons, open and
              close braces may be used instead of in and esac (e.g., case $foo
              {  *) echo bar; }).  The exit status of a case statement is that
              of the executed list; if no list is executed, the exit status is
              zero.

       for name [ in word ... term ] do list done
              where  term  is  either  a newline or a ;.  For each word in the
              specified word list, the parameter name is set to the  word  and
              list is executed.  If in is not used to specify a word list, the
              positional parameters ("$1", "$2", etc.) are used instead.   For
              historical reasons, open and close braces may be used instead of
              do and done (e.g., for i; { echo $i; }).  The exit status  of  a
              for  statement is the last exit status of list; if list is never
              executed, the exit status is zero.

       if list then list [elif list then list] ... [else list] fi
              If the exit status of the first list is zero, the second list is
              executed;  otherwise  the  list  following  the elif, if any, is
              executed with similar consequences.  If all the lists  following
              the  if  and  elifs  fail (i.e., exit with non-zero status), the
              list following the else is executed.  The exit status of  an  if
              statement  is  that of non-conditional list that is executed; if
              no non-conditional list is executed, the exit status is zero.

       select name [ in word ... term ] do list done
              where term is either a newline or a  ;.   The  select  statement
              provides  an automatic method of presenting the user with a menu
              and selecting from it.  An  enumerated  list  of  the  specified
              words  is  printed on standard error, followed by a prompt (PS3,
              normally  `#?  ').   A  number  corresponding  to  one  of   the
              enumerated  words  is then read from standard input, name is set
              to the selected word (or  is  unset  if  the  selection  is  not
              valid), REPLY is set to what was read (leading/trailing space is
              stripped), and list is executed.  If a blank line (i.e., zero or
              more  IFS characters) is entered, the menu is re-printed without
              executing list.  When list completes,  the  enumerated  list  is
              printed if REPLY is null, the prompt is printed and so on.  This
              process is continues until an end-of-file is read, an  interrupt
              is  received  or  a break statement is executed inside the loop.
              If in word ... is omitted, the positional  parameters  are  used
              (i.e.,  "$1",  "$2",  etc.).   For  historical reasons, open and
              close braces may be used instead of do and done (e.g., select i;
              { echo $i; }).  The exit status of a select statement is zero if
              a break statement is used to exit the loop, non-zero otherwise.

       until list do list done
              This works like while, except that the  body  is  executed  only
              while the exit status of the first list is non-zero.

       while list do list done
              A  while is a prechecked loop.  Its body is executed as often as
              the exit status of the first list is zero.  The exit status of a
              while  statement is the last exit status of the list in the body
              of the loop; if the body is not executed,  the  exit  status  is
              zero.

       function name { list }
              Defines  the  function  name.   See  Functions below.  Note that
              redirections specified after a function definition are performed
              whenever  the  function  is  executed,  not  when  the  function
              definition is executed.

       name () command
              Mostly the same as function.  See Functions  below.   Whitespace
              (space or tab) after name will be ignored most of the time.

       time [ -p ] [ pipeline ]
              The  time  reserved  word  is described in the Command Execution
              section.

       (( expression ))
              The arithmetic expression expression is evaluated; equivalent to
              let  "expression".   See  Arithmetic  Expressions  and  the  let
              command below.

       [[ expression ]]
              Similar to the test and [ ... ] commands (described later), with
              the following exceptions:
                o    Field   splitting   and  file  name  generation  are  not
                     performed on arguments.
                o    The -a (and) and -o (or) operators are replaced  with  &&
                     and ||, respectively.
                o    Operators (e.g., -f, =, !, etc.) must be unquoted.
                o    The  second  operand of != and = expressions are patterns
                     (e.g., the comparison in
                                        [[ foobar = f*r ]]
                     succeeds).
                o    There are two additional binary operators: < and >  which
                     return  true  if their first string operand is less than,
                     or   greater   than,   their   second   string   operand,
                     respectively.
                o    The  single  argument  form  of  test, which tests if the
                     argument has non-zero length, is  not  valid  -  explicit
                     operators must be always be used, e.g., instead of
                                              [ str ]
                     use
                                           [[ -n str ]]
                o    Parameter,   command  and  arithmetic  substitutions  are
                     performed  as  expressions   are   evaluated   and   lazy
                     expression   evaluation   is  used  for  the  &&  and  ||
                     operators.  This means that in the statement
                                  [[ -r foo && $(< foo) = b*r ]]
                     the $(< foo) is evaluated if and only  if  the  file  foo
                     exists and is readable.

   Quoting
       Quoting  is used to prevent the shell from treating characters or words
       specially.  There are three methods of quoting:  First,  \  quotes  the
       following  character,  unless it is at the end of a line, in which case
       both the \ and the newline are stripped.  Second, a  single  quote  (')
       quotes  everything  up  to the next single quote (this may span lines).
       Third, a double quote (") quotes all characters, except $, ` and \,  up
       to  the  next unquoted double quote.  $ and ` inside double quotes have
       their  usual  meaning   (i.e.,   parameter,   command   or   arithmetic
       substitution)  except  no field splitting is carried out on the results
       of double-quoted substitutions.  If a \ inside a  double-quoted  string
       is followed by \, $, ` or ", it is replaced by the second character; if
       it is followed by a newline, both the \ and the newline  are  stripped;
       otherwise, both the \ and the character following are unchanged.

       Note:  see  POSIX  Mode below for a special rule regarding sequences of
       the form "...`...\"...`..".

   Aliases
       There are two types of aliases:  normal  command  aliases  and  tracked
       aliases.   Command aliases are normally used as a short hand for a long
       or often used  command.   The  shell  expands  command  aliases  (i.e.,
       substitutes  the alias name for its value) when it reads the first word
       of a command.  An expanded alias is  re-processed  to  check  for  more
       aliases.  If a command alias ends in a space or tab, the following word
       is also checked for alias expansion.  The alias expansion process stops
       when  a word that is not an alias is found, when a quoted word is found
       or when an alias word that is currently being expanded is found.

       The following command aliases are defined automatically by the shell:
              autoload='typeset -fu'
              functions='typeset -f'
              hash='alias -t'
              history='fc -l'
              integer='typeset -i'
              local='typeset'
              login='exec login'
              newgrp='exec newgrp'
              nohup='nohup '
              r='fc -e -'
              stop='kill -STOP'
              suspend='kill -STOP $$'
              type='whence -v'

       Tracked aliases allow the shell to remember where it found a particular
       command.   The  first  time  the shell does a path search for a command
       that is marked as a tracked alias,  it  saves  the  full  path  of  the
       command.   The  next time the command is executed, the shell checks the
       saved path to see that it is still valid, and if so,  avoids  repeating
       the path search.  Tracked aliases can be listed and created using alias
       -t.  Note that changing the PATH parameter clears the saved  paths  for
       all  tracked  aliases.   If  the  trackall  option is set (i.e., set -o
       trackall or set -h), the shell tracks all commands.  This option is set
       automatically for non-interactive shells.  For interactive shells, only
       the following commands are automatically tracked: cat, cc,  chmod,  cp,
       date, ed, emacs, grep, ls, mail, make, mv, pr, rm, sed, sh, vi and who.

   Substitution
       The  first  step  the  shell  takes in executing a simple-command is to
       perform substitutions on the words of the  command.   There  are  three
       kinds  of  substitution:  parameter, command and arithmetic.  Parameter
       substitutions, which are described in detail in the next section,  take
       the   form  $name  or  ${...};  command  substitutions  take  the  form
       $(command) or `command`; and arithmetic  substitutions  take  the  form
       $((expression)).

       If  a substitution appears outside of double quotes, the results of the
       substitution are generally subject to word or field splitting according
       to the current value of the IFS parameter.  The IFS parameter specifies
       a list of characters which are used to break a string up  into  several
       words;  any  characters from the set space, tab and newline that appear
       in the IFS characters are called IFS white space.  Sequences of one  or
       more  IFS  white space characters, in combination with zero or one non-
       IFS white space characters delimit a field.  As a special case, leading
       and  trailing IFS white space is stripped (i.e., no leading or trailing
       empty field is created by it); leading or trailing non-IFS white  space
       does  create an empty field.  Example: if IFS is set to `<space>:', the
       sequence of  characters  `<space>A<space>:<space><space>B::D'  contains
       four  fields:  `A', `B', `' and `D'.  Note that if the IFS parameter is
       set to the null string, no field splitting is done; if the parameter is
       unset, the default value of space, tab and newline is used.

       The  results  of  substitution  are,  unless  otherwise specified, also
       subject to brace expansion and file name expansion  (see  the  relevant
       sections below).

       A  command  substitution  is  replaced  by  the output generated by the
       specified  command,  which  is  run  in  a  subshell.   For  $(command)
       substitutions,  normal  quoting  rules are used when command is parsed,
       however, for the `command` form, a \ followed by any of $, `  or  \  is
       stripped  (a  \  followed  by  any other character is unchanged).  As a
       special case in command substitutions, a command of the form < file  is
       interpreted  to  mean substitute the contents of file ($(< foo) has the
       same effect as $(cat foo), but  it  is  carried  out  more  efficiently
       because no process is started).
       NOTE:  $(command)  expressions  are  currently  parsed  by  finding the
       matching parenthesis, regardless of quoting.  This  will  hopefully  be
       fixed soon.

       Arithmetic  substitutions  are  replaced  by the value of the specified
       expression.  For example, the command echo $((2+3*4)) prints  14.   See
       Arithmetic Expressions for a description of an expression.

   Parameters
       Parameters  are  shell variables; they can be assigned values and their
       values can be accessed using a  parameter  substitution.   A  parameter
       name is either one of the special single punctuation or digit character
       parameters described below, or  a  letter  followed  by  zero  or  more
       letters  or  digits  (`_'  counts  as a letter).  The later form can be
       treated as arrays by appending an array index of the form: [expr] where
       expr  is an arithmetic expression.  Array indices are currently limited
       to the range 0 through 1023, inclusive.  Parameter  substitutions  take
       the  form  $name,  ${name}  or ${name[expr]}, where name is a parameter
       name.  If substitution  is  performed  on  a  parameter  (or  an  array
       parameter element) that is not set, a null string is substituted unless
       the nounset option (set -o nounset or set -u) is set, in which case  an
       error occurs.

       Parameters  can  be  assigned  values  in a number of ways.  First, the
       shell implicitly sets some parameters like #, PWD, etc.;  this  is  the
       only  way  the  special  single  character parameters are set.  Second,
       parameters are  imported  from  the  shell's  environment  at  startup.
       Third,  parameters  can  be  assigned  values  on the command line, for
       example, `FOO=bar' sets the parameter FOO to  bar;  multiple  parameter
       assignments  can  be  given  on  a  single command line and they can be
       followed by a simple-command, in which  case  the  assignments  are  in
       effect  only for the duration of the command (such assignments are also
       exported, see below for implications of  this).   Note  that  both  the
       parameter  name and the = must be unquoted for the shell to recognize a
       parameter assignment.  The fourth way of setting a  parameter  is  with
       the  export,  readonly  and typeset commands; see their descriptions in
       the Command  Execution  section.   Fifth,  for  and  select  loops  set
       parameters  as  well as the getopts, read and set -A commands.  Lastly,
       parameters can be assigned values  using  assignment  operators  inside
       arithmetic  expressions (see Arithmetic Expressions below) or using the
       ${name=value} form of parameter substitution (see below).

       Parameters with the export attribute (set using the export  or  typeset
       -x  commands,  or by parameter assignments followed by simple commands)
       are put in the environment (see environ(7))  of  commands  run  by  the
       shell as name=value pairs.  The order in which parameters appear in the
       environment of a command is unspecified.  When the shell starts up,  it
       extracts   parameters   and  their  values  from  its  environment  and
       automatically sets the export attribute for those parameters.

       Modifiers can be applied to the ${name} form of parameter substitution:

       ${name:-word}
              if name is set and not null, it is substituted,  otherwise  word
              is substituted.

       ${name:+word}
              if  name  is  set  and  not null, word is substituted, otherwise
              nothing is substituted.

       ${name:=word}
              if name is set and not null, it is substituted, otherwise it  is
              assigned word and the resulting value of name is substituted.

       ${name:?word}
              if  name  is set and not null, it is substituted, otherwise word
              is printed on standard error (preceded by name:)  and  an  error
              occurs (normally causing termination of a shell script, function
              or .-script).  If word is omitted the string `parameter null  or
              not set' is used instead.

       In  the  above  modifiers,  the  :  can  be  omitted, in which case the
       conditions only depend on name being set (as opposed  to  set  and  not
       null).   If  word  is  needed, parameter, command, arithmetic and tilde
       substitution are performed on it; if word is  not  needed,  it  is  not
       evaluated.

       The following forms of parameter substitution can also be used:

       ${#name}
              The  number  of  positional parameters if name is *, @ or is not
              specified, or the length of the string value of parameter name.

       ${#name[*]}, ${#name[@]}
              The number of elements in the array name.

       ${name#pattern}, ${name##pattern}
              If pattern matches the beginning of the value of parameter name,
              the  matched text is deleted from the result of substitution.  A
              single # results in the shortest match, two #'s results  in  the
              longest match.

       ${name%pattern}, ${name%%pattern}
              Like  ${..#..}  substitution, but it deletes from the end of the
              value.

       The following special parameters are implicitly set by  the  shell  and
       cannot be set directly using assignments:

       !      Process  id  of  the  last  background  process  started.  If no
              background processes have been started,  the  parameter  is  not
              set.

       #      The number of positional parameters (i.e., $1, $2, etc.).

       $      The process ID of the shell, or the PID of the original shell if
              it is a subshell.

       -      The concatenation of the current single letter options (see  set
              command below for list of options).

       ?      The  exit  status of the last non-asynchronous command executed.
              If the last command was killed by a signal, $?  is  set  to  128
              plus the signal number.

       0      The  name  the  shell  was  invoked with (i.e., argv[0]), or the
              command-name if it was  invoked  with  the  -c  option  and  the
              command-name  was  supplied,  or  the  file  argument, if it was
              supplied.  If the posix option is not set, $0 is the name of the
              current function or script.

       1 ... 9
              The  first  nine positional parameters that were supplied to the
              shell, function or .-script.  Further positional parameters  may
              be accessed using ${number}.

       *      All  positional  parameters  (except  parameter  0), i.e., $1 $2
              $3....   If  used  outside  of  double  quotes,  parameters  are
              separate  words (which are subjected to word splitting); if used
              within double quotes, parameters  are  separated  by  the  first
              character  of  the  IFS parameter (or the empty string if IFS is
              null).

       @      Same as $*, unless it is used inside  double  quotes,  in  which
              case  a separate word is generated for each positional parameter
              - if there are no positional parameters, no  word  is  generated
              ("$@" can be used to access arguments, verbatim, without loosing
              null arguments or splitting arguments with spaces).

       The following parameters are set and/or used by the shell:

       _ (underscore)
              When  an  external  command  is  executed  by  the  shell,  this
              parameter  is  set  in the environment of the new process to the
              path  of  the  executed  command.   In  interactive  use,   this
              parameter  is  also  set in the parent shell to the last word of
              the previous command.  When  MAILPATH  messages  are  evaluated,
              this  parameter  contains the name of the file that changed (see
              MAILPATH parameter below).

       CDPATH Search path for the cd built-in command.  Works the same way  as
              PATH  for those directories not beginning with / in cd commands.
              Note that if CDPATH is set and does not contain . nor  an  empty
              path, the current directory is not searched.

       COLUMNS
              Set  to  the  number  of  columns  on  the  terminal  or window.
              Currently set to the cols value as reported by stty(1)  if  that
              value  is  non-zero.   This parameter is used by the interactive
              line editing modes, and by select, set -o and kill  -l  commands
              to format information in columns.

       EDITMODE
              If  set,  this  parameter controls the command line editing mode
              for interactive shells.  If  the  last  component  of  the  path
              specified  in  this  parameter  contains the string vi, emacs or
              gmacs, the vi, emacs or gmacs (Gosling emacs)  editing  mode  is
              enabled, respectively.

       EDITOR If  the VISUAL parameter is not set, this parameter controls the
              command line editing mode for interactive shells.  See  EDITMODE
              parameter above for how this works.

       ENV    If this parameter is found to be set after any profile files are
              executed, the expanded value is used as a shell  start-up  file.
              It typically contains function and alias definitions.

       ERRNO  Integer  value  of  the  shell's errno variable -- indicates the
              reason the last system call failed.

              Not implemented yet.

       EXECSHELL
              If set, this parameter is assumed to contain the shell  that  is
              to  be  used to execute commands that execve(2) fails to execute
              and which do not start with a `#! shell' sequence.

       FCEDIT The editor used by the fc command (see below).

       FPATH  Like PATH, but used when an undefined function  is  executed  to
              locate the file defining the function.  It is also searched when
              a command can't be found using PATH.  See  Functions  below  for
              more information.

       HISTFILE
              The  name  of the file used to store history.  When assigned to,
              history is  loaded  from  the  specified  file.   Also,  several
              invocations  of the shell running on the same machine will share
              history if their HISTFILE parameters all point at the same file.
              NOTE: if HISTFILE isn't set, no history file is used.   This  is
              different   from   the   original   Korn   shell,   which   uses
              $HOME/.sh_history; in future,  pdksh  may  also  use  a  default
              history file.

       HISTSIZE
              The number of commands normally stored for history, default 128.

       HOME   The   default  directory  for  the  cd  command  and  the  value
              substituted for an unqualified ~ (see Tilde Expansion below).

       IFS    Internal field separator, used during substitution  and  by  the
              read  command, to split values into distinct arguments; normally
              set to space, tab  and  newline.   See  Substitution  above  for
              details.
              Note:  this  parameter is not imported from the environment when
              the shell is started.

       KSH_VERSION
              The version of shell  and  the  date  the  version  was  created
              (readonly).  See also the version commands in Emacs Editing Mode
              and Vi Editing Mode sections, below.

       LINENO The line  number  of  the  function  or  shell  script  that  is
              currently being executed.

       LINES  Set to the number of lines on the terminal or window.

              Not implemented yet.

       MAIL   If  set, the user will be informed of the arrival of mail in the
              named file.  This parameter is ignored if the MAILPATH parameter
              is set.

       MAILCHECK
              How  often,  in  seconds,  the  shell will check for mail in the
              file(s) specified by MAIL or MAILPATH.  If 0, the  shell  checks
              before each prompt.  The default is 600 (10 minutes).

       MAILPATH
              A  list  of  files  to  be  checked for mail.  The list is colon
              separated, and each file may be followed by a ? and a message to
              be  printed  if  new  mail  has arrived.  Command, parameter and
              arithmetic substitution is performed on the message, and, during
              substitution,  the  parameter  $_ contains the name of the file.
              The default message is you have mail in $_.

       OLDPWD The  previous  working  directory.   Unset   if   cd   has   not
              successfully  changed directories since the shell started, or if
              the shell doesn't know where it is.

       OPTARG When using getopts,  it  contains  the  argument  for  a  parsed
              option, if it requires one.

       OPTIND The  index  of  the  last argument processed when using getopts.
              Assigning  1  to  this  parameter  causes  getopts  to   process
              arguments from the beginning the next time it is invoked.

       PATH   A  colon  separated  list  of directories that are searched when
              looking for commands and .'d files.  An empty  string  resulting
              from  a  leading  or  trailing  colon, or two adjacent colons is
              treated as a `.', the current directory.

       POSIXLY_CORRECT
              If set, this parameter causes the posix option  to  be  enabled.
              See POSIX Mode below.

       PPID   The process ID of the shell's parent (readonly).

       PS1    PS1  is  the  primary prompt for interactive shells.  Parameter,
              command and arithmetic substitutions are  performed,  and  !  is
              replaced with the current command number (see fc command below).
              A literal ! can be put in the prompt by placing !! in PS1.  Note
              that  since  the command line editors try to figure out how long
              the prompt is (so they know  how  far  it  is  to  edge  of  the
              screen), escape codes in the prompt tend to mess things up.  You
              can tell the shell not  to  count  certain  sequences  (such  as
              escape  codes)  by  prefixing  your  prompt  with a non-printing
              character (such as control-A) followed by a carriage return  and
              then   delimiting   the  escape  codes  with  this  non-printing
              character.  If  you  don't  have  any  non-printing  characters,
              you're  out  of luck...  BTW, don't blame me for this hack; it's
              in the original ksh.  Default is `$ ' for non-root  users,  `# '
              for root..

       PS2    Secondary  prompt  string, by default `> ', used when more input
              is needed to complete a command.

       PS3    Prompt used by select statement when reading a  menu  selection.
              Default is `#? '.

       PS4    Used  to  prefix  commands  that  are  printed  during execution
              tracing (see set -x  command  below).   Parameter,  command  and
              arithmetic  substitutions  are  performed  before it is printed.
              Default is `+ '.

       PWD    The current working directory.  Maybe unset  or  null  if  shell
              doesn't know where it is.

       RANDOM A   simple  random  number  generator.   Every  time  RANDOM  is
              referenced, it is assigned the next number in  a  random  number
              series.   The  point  in  the  series  can be set by assigning a
              number to RANDOM (see rand(3)).

       REPLY  Default parameter for the read command if no  names  are  given.
              Also  used  in select loops to store the value that is read from
              standard input.

       SECONDS
              The number of  seconds  since  the  shell  started  or,  if  the
              parameter  has  been  assigned  an  integer value, the number of
              seconds since the assignment plus the value that was assigned.

       TMOUT  If set to  a  positive  integer  in  an  interactive  shell,  it
              specifies  the maximum number of seconds the shell will wait for
              input after printing the primary prompt (PS1).  If the  time  is
              exceeded, the shell exits.

       TMPDIR The  directory  shell  temporary  files are created in.  If this
              parameter is not set, or does not contain the absolute path of a
              writable directory, temporary files are created in /tmp.

       VISUAL If  set,  and  EDITMODE  is  unset,  this parameter controls the
              command line editing mode for interactive shells.  If  the  last
              component  of  the path specified in this parameter contains the
              string vi, emacs or gmacs,  the  vi,  emacs  or  gmacs  (Gosling
              emacs) editing mode is enabled, respectively.

   Tilde Expansion
       Tilde expansion, which is done in parallel with parameter substitution,
       is done on words starting with an unquoted ~.  The characters following
       the  tilde,  up to the first /, if any, are assumed to be a login name.
       If the login name is empty, + or -, the value  of  the  HOME,  PWD,  or
       OLDPWD parameter is substituted, respectively.  Otherwise, the password
       file is searched for the  login  name,  and  the  tilde  expression  is
       substituted  with  the user's home directory.  If the login name is not
       found in the password file or if any quoting or parameter  substitution
       occurs in the login name, no substitution is performed.

       In  parameter  assignments  (those  preceding a simple-command or those
       occurring in the arguments of alias, export,  readonly,  and  typeset),
       tilde  expansion  is done after any unquoted colon (:), and login names
       are also delimited by colons.

       The home directory of previously expanded login names  are  cached  and
       re-used.   The  alias -d command may be used to list, change and add to
       this cache (e.g., `alias -d fac=/usr/local/facilities; cd ~fac/bin').

   Brace Expansion (alternation)
       Brace expressions, which take the form
              prefix{str1,...,strN}suffix
       are expanded to N words, each of which is the concatenation of  prefix,
       stri  and  suffix  (e.g.,  `a{c,b{X,Y},d}e'  expands to four word: ace,
       abXe, abYe, and ade).  As noted in the example, brace  expressions  can
       be  nested  and  the resulting words are not sorted.  Brace expressions
       must contain an unquoted comma (,) for expansion to occur (i.e., {} and
       {foo}  are  not  expanded).   Brace  expansion  is  carried  out  after
       parameter substitution and before file name generation.

   File Name Patterns
       A file name pattern is a word containing one or more unquoted  ?  or  *
       characters or [..] sequences.  Once brace expansion has been performed,
       the shell replaces file name patterns with the sorted names of all  the
       files  that  match  the  pattern  (if  no files match, the word is left
       unchanged).  The pattern elements have the following meaning:

       ?      matches any single character.

       *      matches any sequence of characters.

       [..]   matches any of the characters inside the  brackets.   Ranges  of
              characters can be specified by separating two characters by a -,
              e.g., [a0-9] matches the letter a or any  digit.   In  order  to
              represent itself, a - must either be quoted or the first or last
              character in the character list.  Similarly, a ] must be  quoted
              or  the  first  character  in the list if it is represent itself
              instead of the end of the list.  Also, a  !   appearing  at  the
              start  of  the  list  has  special  meaning  (see  below), so to
              represent itself it must be quoted or appear later in the list.

       [!..]  like [..], except  it  matches  any  character  not  inside  the
              brackets.

       *(pattern| ... |pattern)
              matches  any  string  of  characters  that  matches zero or more
              occurrences of the specified  patterns.   Example:  the  pattern
              *(foo|bar)  matches  the  strings `', `foo', `bar', `foobarfoo',
              etc..

       +(pattern| ... |pattern)
              matches any string  of  characters  that  matches  one  or  more
              occurrences  of  the  specified  patterns.  Example: the pattern
              +(foo|bar) matches the strings `foo', `bar', `foobarfoo', etc..

       ?(pattern| ... |pattern)
              matches the empty string or a string that  matches  one  of  the
              specified   patterns.   Example:  the  pattern  ?(foo|bar)  only
              matches the strings `', `foo' and `bar'.

       @(pattern| ... |pattern)
              matches a string that matches one  of  the  specified  patterns.
              Example:  the  pattern @(foo|bar) only matches the strings `foo'
              and `bar'.

       !(pattern| ... |pattern)
              matches any string that does not  match  one  of  the  specified
              patterns.   Examples: the pattern !(foo|bar) matches all strings
              except `foo' and `bar'; the pattern !(*) matches no strings; the
              pattern !(?)* matches all strings (think about it).

       Note that pdksh currently never matches . and .., but the original ksh,
       Bourne sh and bash do, so this may have to change (too bad).

       Note that none of the above pattern elements match either a period  (.)
       at the start of a file name or a slash (/), even if they are explicitly
       used in a [..] sequence; also, the names . and ..  are  never  matched,
       even by the pattern .*.

       If  the  markdirs  option is set, any directories that result from file
       name generation are marked with a trailing /.

       The  POSIX  character  classes  (i.e.,  [:class-name:]  inside  a  [..]
       expression) are not yet implemented.

   Input/Output Redirection
       When  a  command  is  executed, its standard input, standard output and
       standard error (file descriptors 0, 1 and 2, respectively) are normally
       inherited  from  the  shell.   Three exceptions to this are commands in
       pipelines, for which standard input and/or standard  output  are  those
       set  up by the pipeline, asynchronous commands created when job control
       is disabled, for which standard input  is  initially  set  to  be  from
       /dev/null,  and  commands  for  which any of the following redirections
       have been specified:

       > file standard output is redirected to file.  If file does not  exist,
              it  is  created;  if  it  does  exist, is a regular file and the
              noclobber option is set, an error occurs, otherwise the file  is
              truncated.   Note  that  this  means the command cmd < foo > foo
              will open foo for reading and then truncate it when it opens  it
              for writing, before cmd gets a chance to actually read foo.

       >| file
              same  as  >, except the file is truncated, even if the noclobber
              option is set.

       >> file
              same as >, except the file  an  existing  file  is  appended  to
              instead  of being truncated.  Also, the file is opened in append
              mode, so writes always go to the end of the file (see open(2)).

       < file standard input is redirected from  file,  which  is  opened  for
              reading.

       <> file
              same as <, except the file is opened for reading and writing.

       << marker
              after   reading   the  command  line  containing  this  kind  of
              redirection (called a here document),  the  shell  copies  lines
              from  the  command  source  into  a  temporary file until a line
              matching marker is read.  When the command is executed, standard
              input is redirected from the temporary file.  If marker contains
              no quoted characters, the contents of  the  temporary  file  are
              processed  as if enclosed in double quotes each time the command
              is executed, so parameter, command and arithmetic  substitutions
              are  performed, along with backslash (\) escapes for $, `, \ and
              \newline.  If multiple here  documents  are  used  on  the  same
              command line, they are saved in order.

       <<- marker
              same  as  <<, except leading tabs are stripped from lines in the
              here document.

       <& fd  standard input is duplicated from file descriptor fd.  fd can be
              a  single  digit,  indicating  the  number  of  an existing file
              descriptor,  the  letter  p,  indicating  the  file   descriptor
              associated  with  the  output  of the current co-process, or the
              character -, indicating standard input is to be closed.

       >& fd  same as <&, except the operation is done on standard output.

       In  any  of  the  above  redirections,  the  file  descriptor  that  is
       redirected  (i.e., standard input or standard output) can be explicitly
       given by preceding the redirection with  a  single  digit.   Parameter,
       command  and  arithmetic substitutions, tilde substitutions and (if the
       shell is interactive) file name generation are  all  performed  on  the
       file,  marker and fd arguments of redirections.  Note however, that the
       results of any file name generation are only used if a single  file  is
       matched;  if  multiple  files  match, the word with the unexpanded file
       name generation characters is used.  Note that  in  restricted  shells,
       redirections which can create files cannot be used.

       For  simple-commands,  redirections may appear anywhere in the command,
       for compound-commands (if  statements,  etc.),  any  redirections  must
       appear  at  the  end.   Redirections  are processed after pipelines are
       created and in the order they are given, so
              cat /foo/bar 2>&1 > /dev/null | cat -n
       will print an error with a line number prepended to it.

   Arithmetic Expressions
       Integer arithmetic expressions can be used with the let command, inside
       $((..))  expressions,  inside  array  references (e.g., name[expr]), as
       numeric arguments  to  the  test  command,  and  as  the  value  of  an
       assignment to an integer parameter.

       Expression  may  contain  alpha-numeric  parameter  identifiers,  array
       references,  and  integer  constants  and  may  be  combined  with  the
       following  C  operators  (listed  and  grouped  in  increasing order of
       precedence).

       Unary operators:
              + - ! ~ ++ --

       Binary operators:
              ,
              = *= /= %= += -= <<= >>= &= ^= |=
              ||
              &&
              |
              ^
              &
              == !=
              < <= >= >
              << >>
              + -
              * / %

       Ternary operator:
              ?: (precedence is immediately higher than assignment)

       Grouping operators:
              ( )

       Integer constants may be  specified  with  arbitrary  bases  using  the
       notation  base#number,  where  base is a decimal integer specifying the
       base, and number is a number in the specified base.

       The operators are evaluated as follows:

              unary +
                     result is the argument (included for completeness).

              unary -
                     negation.

              !      logical not; the result is 1 if argument is  zero,  0  if
                     not.

              ~      arithmetic (bit-wise) not.

              ++     increment;  must be applied to a parameter (not a literal
                     or other expression) - the parameter is incremented by 1.
                     When  used  as  a  prefix  operator,  the  result  is the
                     incremented value  of  the  parameter,  when  used  as  a
                     postfix operator, the result is the original value of the
                     parameter.

              --     similar to ++, except the parameter is decremented by 1.

              ,      separates two arithmetic expressions; the left hand  side
                     is  evaluated first, then the right.  The result is value
                     of the expression on the right hand side.

              =      assignment; variable on the left is set to the  value  on
                     the right.

              *= /= %= += -= <<= >>= &= ^= |=
                     assignment  operators;  <var> <op>= <expr> is the same as
                     <var> = <var> <op> ( <expr> ).

              ||     logical or; the result is 1 if either  argument  is  non-
                     zero,  0 if not.  The right argument is evaluated only if
                     the left argument is zero.

              &&     logical and; the result is 1 if both arguments  are  non-
                     zero,  0 if not.  The right argument is evaluated only if
                     the left argument is non-zero.

              |      arithmetic (bit-wise) or.

              ^      arithmetic (bit-wise) exclusive-or.

              &      arithmetic (bit-wise) and.

              ==     equal; the result is 1 if both arguments are equal, 0  if
                     not.

              !=     not equal; the result is 0 if both arguments are equal, 1
                     if not.

              <      less than; the result is 1 if the left argument  is  less
                     than the right, 0 if not.

              <= >= >
                     less  than or equal, greater than or equal, greater than.
                     See <.

              << >>  shift left (right); the result is the left argument  with
                     its  bits shifted left (right) by the amount given in the
                     right argument.

              + - * /
                     addition, subtraction, multiplication, and division.

              %      remainder; the result is the remainder of the division of
                     the  left  argument by the right.  The sign of the result
                     is unspecified if either argument is negative.

              <arg1> ? <arg2> : <arg3>
                     if <arg1> is non-zero, the result  is  <arg2>,  otherwise
                     <arg3>.

   Co-Processes
       A  co-process,  which is a pipeline created with the |& operator, is an
       asynchronous process that the shell can both write to (using print  -p)
       and  read from (using read -p).  The input and output of the co-process
       can also be manipulated using >&p and <&p  redirections,  respectively.
       Once  a co-process has been started, another can't be started until the
       co-process exits, or until the co-process  input  has  been  redirected
       using  an exec n>&p redirection.  If a co-process's input is redirected
       in this way, the next co-process to be started will  share  the  output
       with  the first co-process, unless the output of the initial co-process
       has been redirected using an exec n<&p redirection.

       Some notes concerning co-processes:
         o    the only way to close the co-process input  (so  the  co-process
              reads  an  end-of-file)  is  to redirect the input to a numbered
              file descriptor and then close that file descriptor (e.g.,  exec
              3>&p;exec 3>&-).
         o    in  order  for  co-processes to share a common output, the shell
              must keep the write portion of the output pipe open.  This means
              that  end  of  file  will not be detected until all co-processes
              sharing the co-process output have exited (when they  all  exit,
              the  shell closes its copy of the pipe).  This can be avoided by
              redirecting the output to a numbered file  descriptor  (as  this
              also  causes  the  shell  to  close  its  copy).  Note that this
              behaviour is slightly different from  the  original  Korn  shell
              which  closes  its copy of the write portion of the co-process's
              output when the most recently  started  co-process  (instead  of
              when all sharing co-processes) exits.
         o    print -p will ignore SIGPIPE signals during writes if the signal
              is not being trapped or ignored; the same is not true if the co-
              process input has been duplicated to another file descriptor and
              print -un is used.

   Functions
       Functions are defined using either Korn shell function name  syntax  or
       the  Bourne/POSIX  shell  name()  syntax  (see below for the difference
       between the two forms).  Functions are like .-scripts in that they  are
       executed  in  the current environment, however, unlike .-scripts, shell
       arguments (i.e., positional parameters, $1,  etc.)  are  never  visible
       inside  them.  When the shell is determining the location of a command,
       functions are searched after  special  built-in  commands,  and  before
       regular and non-regular built-ins, and before the PATH is searched.

       An  existing  function  may be deleted using unset -f function-name.  A
       list of functions can be obtained using typeset  +f  and  the  function
       definitions  can  be  listed  using  typeset -f.  autoload (which is an
       alias for typeset -fu) may be used to create undefined functions;  when
       an  undefined  function  is  executed,  the  shell  searches  the  path
       specified in the FPATH parameter for a file with the same name  as  the
       function, which, if found is read and executed.  If after executing the
       file, the named function is  found  to  be  defined,  the  function  is
       executed,  otherwise, the normal command search is continued (i.e., the
       shell searches the regular built-in command table and PATH).  Note that
       if  a command is not found using PATH, an attempt is made to autoload a
       function using FPATH (this is an undocumented feature of  the  original
       Korn shell).

       Functions  can  have two attributes, trace and export, which can be set
       with typeset -ft and typeset -fx, respectively.  When a traced function
       is  executed,  the shell's xtrace option is turned on for the functions
       duration, otherwise the  xtrace  option  is  turned  off.   The  export
       attribute  of  functions  is  currently not used.  In the original Korn
       shell, exported  functions  are  visible  to  shell  scripts  that  are
       executed.

       Since   functions  are  executed  in  the  current  shell  environment,
       parameter assignments made  inside  functions  are  visible  after  the
       function  completes.   If  this  is not the desired effect, the typeset
       command can be used inside a function  to  create  a  local  parameter.
       Note  that  special  parameters  (e.g., $$, $!) can't be scoped in this
       way.

       The exit status of a function is that of the last command  executed  in
       the  function.   A function can be made to finish immediately using the
       return command; this may also be used to explicitly  specify  the  exit
       status.

       Functions   defined   with  the  function  reserved  word  are  treated
       differently in the following ways from functions defined  with  the  ()
       notation:
         o    the  $0  parameter  is  set to the name of the function (Bourne-
              style functions leave $0 untouched).
         o    parameter assignments preceding function calls are not  kept  in
              the  shell  environment  (executing  Bourne-style functions will
              keep assignments).
         o    OPTIND is saved/reset and restored on entry and  exit  from  the
              function so getopts can be used properly both inside and outside
              the function (Bourne-style functions leave OPTIND untouched,  so
              using  getopts  inside  a function interferes with using getopts
              outside the function).
              Bourne-style function definitions  take  precedence  over  alias
              dereferences  and remove alias definitions upon encounter, while
              aliases take  precedence  over  Korn-style  functions.   In  the
              future, the following differences will also be added:
         o    A  separate  trap/signal  environment  will  be  used during the
              execution of functions.  This will mean that traps set inside  a
              function  will not affect the shell's traps and signals that are
              not ignored in the shell (but may be trapped)  will  have  their
              default effect in a function.
         o    The  EXIT trap, if set in a function, will be executed after the
              function returns.

   POSIX Mode
       The shell is intended to be POSIX compliant, however,  in  some  cases,
       POSIX behaviour is contrary either to the original Korn shell behaviour
       or to user convenience.  How  the  shell  behaves  in  these  cases  is
       determined  by the state of the posix option (set -o posix) -- if it is
       on, the POSIX behaviour is followed, otherwise it is  not.   The  posix
       option is set automatically when the shell starts up if the environment
       contains  the  POSIXLY_CORRECT  parameter.   (The  shell  can  also  be
       compiled  so  that  it  is  in  POSIX  mode by default, however this is
       usually not desirable).

       The following is a list of things that are affected by the state of the
       posix option:
         o    \"  inside  double  quoted  `..` command substitutions: in posix
              mode, the \" is interpreted when the command is interpreted;  in
              non-posix  mode,  the  backslash  is stripped before the command
              substitution is interpreted.  For example, echo "`echo  \"hi\"`"
              produces `"hi"' in posix mode, `hi' in non-posix mode.  To avoid
              problems, use the $(...)  form of command substitution.
         o    kill -l output: in posix mode, signal names  are  listed  one  a
              single  line;  in  non-posix  mode,  signal  numbers,  names and
              descriptions are printed in columns.  In future,  a  new  option
              (-v perhaps) will be added to distinguish the two behaviours.
         o    echo  options.   In  POSIX  mode,  -e  and -E are not treated as
              options, but printed like other arguments;  in  non-POSIX  mode,
              these options control the interpretation of backslash sequences.
         o    fg exit status: in posix mode, the exit status is 0 if no errors
              occur; in non-posix mode, the exit status is that  of  the  last
              foregrounded job.
         o    eval  exit  status:  if eval gets to see an empty command (e.g.,
              eval "`false`"), its exit status in posix mode will  be  0.   In
              non-posix  mode,  it will be the exit status of the last command
              substitution that was done in the processing of the arguments to
              eval (or 0 if there were no command substitutions).
         o    getopts:  in  posix  mode,  options must start with a -; in non-
              posix mode, options can start with either - or +.
         o    brace expansion (also known  as  alternation):  in  posix  mode,
              brace  expansion is disabled; in non-posix mode, brace expansion
              enabled.  Note that set -o posix (or setting the POSIXLY_CORRECT
              parameter)  automatically  turns  the  braceexpand  option  off,
              however it can be explicitly turned on later.
         o    set -: in posix mode, this does not clear the verbose or  xtrace
              options; in non-posix mode, it does.
         o    set  exit  status: in posix mode, the exit status of set is 0 if
              there are no errors; in non-posix mode, the exit status is  that
              of  any  command  substitutions  performed in generating the set
              command.  For example, `set -- `false`; echo  $?'  prints  0  in
              posix mode, 1 in non-posix mode.  This construct is used in most
              shell scripts that use the old getopt(1) command.
              (DEBIAN NOTE: This is no longer  true  on  Debian  systems.  For
              compatibility with ksh93, set command always returns exit status
              set to 0, regardless of posix or non-posix mode.)
         o    argument expansion  of  alias,  export,  readonly,  and  typeset
              commands: in posix mode, normal argument expansion done; in non-
              posix mode, field splitting, file globing, brace  expansion  and
              (normal)  tilde  expansion  are turned off, and assignment tilde
              expansion is turned on.
         o    signal specification: in posix mode, signals can be specified as
              digits  only  if signal numbers match POSIX values (i.e., HUP=1,
              INT=2, QUIT=3, ABRT=6, KILL=9, ALRM=14, and  TERM=15);  in  non-
              posix mode, signals can be always digits.
         o    alias  expansion: in posix mode, alias expansion is only carried
              out  when  reading  command  words;  in  non-posix  mode,  alias
              expansion  is  carried  out  on any word following an alias that
              ended in a space.  For example, the following for loop
              alias a='for ' i='j'
              a i in 1 2; do echo i=$i j=$j; done
       uses parameter i in posix mode, j in non-posix mode.
         o    test: in posix mode,  the  expression  "-t"  (preceded  by  some
              number  of  "!"  arguments)  is  always true as it is a non-zero
              length string; in non-posix mode, it tests if file descriptor  1
              is  a  tty (i.e., the fd argument to the -t test may be left out
              and defaults to 1).

   Command Execution
       After evaluation of command line arguments, redirections and  parameter
       assignments,  the  type of command is determined: a special built-in, a
       function, a regular built-in or the name of a  file  to  execute  found
       using  the  PATH  parameter.   The  checks are made in the above order.
       Special built-in commands differ from other commands in that  the  PATH
       parameter is not used to find them, an error during their execution can
       cause a non-interactive shell to exit and  parameter  assignments  that
       are  specified before the command are kept after the command completes.
       Just to confuse things, if the posix option  is  turned  off  (see  set
       command  below) some special commands are very special in that no field
       splitting,  file  globing,  brace  expansion  nor  tilde  expansion  is
       performed  on  arguments  that look like assignments.  Regular built-in
       commands are different only in that the PATH parameter is not  used  to
       find them.

       The  original  ksh  and  POSIX  differ  somewhat  in which commands are
       considered special or regular:

       POSIX special commands

              .          continue   exit       return     trap
              :          eval       export     set        unset
              break      exec       readonly   shift

       Additional ksh special commands

              builtin    times      typeset

       Very special commands (non-posix mode)

              alias      readonly   set        typeset

       POSIX regular commands

              alias      command    fg         kill       umask
              bg         false      getopts    read       unalias
              cd         fc         jobs       true       wait

       Additional ksh regular commands

              [          let        pwd        ulimit
              echo       print      test       whence

       In the future, the additional ksh special and regular commands  may  be
       treated differently from the POSIX special and regular commands.

       Once  the  type  of  the  command has been determined, any command line
       parameter assignments are performed and exported for  the  duration  of
       the command.

       The following describes the special and regular built-in commands:

       . file [arg1 ...]
              Execute  the  commands  in file in the current environment.  The
              file is searched for in the directories of PATH.   If  arguments
              are  given, the positional parameters may be used to access them
              while file is being executed.  If no arguments  are  given,  the
              positional  parameters  are those of the environment the command
              is used in.

       : [ ... ]
              The null command.  Exit status is set to zero.

       alias [ -d | +-t [-r] ] [+-px] [+-] [name1[=value1] ...]
              Without arguments,  alias  lists  all  aliases.   For  any  name
              without  a value, the existing alias is listed.  Any name with a
              value defines an alias (see Aliases above).

              When listing aliases, one of  two  formats  is  used:  normally,
              aliases  are  listed  as  name=value,  where value is quoted; if
              options were preceded with + or a lone + is given on the command
              line,  only  name  is printed.  In addition, if the -p option is
              used, each alias is prefixed with the string "alias ".

              The -x option sets (+x clears) the export attribute of an alias,
              or,  if  no  names  are given, lists the aliases with the export
              attribute (exporting an alias has no affect).

              The  -t  option  indicates  that  tracked  aliases  are  to   be
              listed/set (values specified on the command line are ignored for
              tracked aliases).  The -r  option  indicates  that  all  tracked
              aliases are to be reset.

              The  -d  causes  directory  aliases,  which  are  used  in tilde
              expansion, to be listed or set (see Tilde Expansion above).

       bg [job ...]
              Resume the specified stopped job(s) in the  background.   If  no
              jobs  are  specified,  %+  is  assumed.   This  command  is only
              available on systems which support job control.  See Job Control
              below for more information.

       bind [-m] [key[=editing-command] ...]
              Set   or   view   the   current   emacs   command   editing  key
              bindings/macros.  See Emacs Editing Mode below  for  a  complete
              description.

       break [level]
              break  exits the levelth inner most for, select, until, or while
              loop.  level defaults to 1.

       builtin command [arg1 ...]
              Execute the built-in command command.

       cd [-LP] [dir]
              Set the working directory to dir.  If the  parameter  CDPATH  is
              set,  it lists directories to search in for dir.  An empty entry
              in the CDPATH entry means the current directory.  If a non-empty
              directory  from  CDPATH  is  used,  the  resulting  full path is
              printed to  standard  output.   If  dir  is  missing,  the  home
              directory  $HOME  is  used.   If  dir is -, the previous working
              directory is used (see OLDPWD parameter).  If -L option (logical
              path)  is used or if the physical option (see set command below)
              isn't set, references to .. in dir are relative to the path used
              get  to  the directory.  If -P option (physical path) is used or
              if the physical option is set, .. is relative to the  filesystem
              directory  tree.   The  PWD and OLDPWD parameters are updated to
              reflect the current and old wording directory, respectively.

       cd [-LP] old new
              The string new is substituted for old in the current  directory,
              and the shell attempts to change to the new directory.

       command [-pvV] cmd [arg1 ...]
              If  neither  the  -v  nor  -V options are given, cmd is executed
              exactly as if the command  had  not  been  specified,  with  two
              exceptions:  first,  cmd cannot be a shell function, and second,
              special  built-in  commands  lose   their   specialness   (i.e.,
              redirection  and  utility errors do not cause the shell to exit,
              and command assignments are not permanent).  If the -p option is
              given,  a  default  search  path  is used instead of the current
              value of PATH (the actual value of the default  path  is  system
              dependent: on POSIXish systems, it is the value returned by
                                      getconf CS_PATH
              ).

              If the -v option is given, instead of executing cmd, information
              about what would be executed is given (and the same is done  for
              arg1  ...):  for  special  and  regular  built-in  commands  and
              functions, their  names  are  simply  printed,  for  aliases,  a
              command  that defines them is printed, and for commands found by
              searching the PATH parameter, the full path of  the  command  is
              printed.   If  no  command  is  be found, (i.e., the path search
              fails), nothing is printed and command  exits  with  a  non-zero
              status.   The -V option is like the -v option, except it is more
              verbose.

       continue [levels]
              continue jumps to the beginning of the levelth inner  most  for,
              select, until, or while loop.  level defaults to 1.

       echo [-neE] [arg ...]
              Prints  its  arguments  (separated  by  spaces)  followed  by  a
              newline, to standard out.  The newline is suppressed if  any  of
              the  arguments  contain  the  backslash  sequence \c.  See print
              command below for a list of other backslash sequences  that  are
              recognized.

              The  options  are  provided  for  compatibility  with  BSD shell
              scripts:  -n  suppresses  the  trailing  newline,   -e   enables
              backslash interpretation (a no-op, since this is normally done),
              and -E which suppresses backslash interpretation.  If the  posix
              option  is set, only the first argument is treated as an option,
              and only if it is exactly -n.

       eval command ...
              The arguments are concatenated (with  spaces  between  them)  to
              form a single string which the shell then parses and executes in
              the current environment.

       exec [command [arg ...]]
              The command is executed without  forking,  replacing  the  shell
              process.

              If  no  arguments are given, any IO redirection is permanent and
              the shell is not replaced.  Any file descriptors greater than  2
              which are opened or dup(2)-ed in this way are not made available
              to other executed commands (i.e., commands that are not built-in
              to the shell).  Note that the Bourne shell differs here: it does
              pass these file descriptors on.
              (DEBIAN NOTE: when the shell is called as /bin/sh, it does  pass
              these file descriptors on, like the Bourne shell.)

       exit [status]
              The  shell  exits  with the specified exit status.  If status is
              not specified, the exit status is the current  value  of  the  ?
              parameter.

       export [-p] [parameter[=value]] ...
              Sets  the  export  attribute  of the named parameters.  Exported
              parameters are passed in the environment to  executed  commands.
              If values are specified, the named parameters also assigned.

              If no parameters are specified, the names of all parameters with
              the export attribute are printed one per  line,  unless  the  -p
              option  is  used,  in  which  case  export commands defining all
              exported parameters, including their values, are printed.

       false  A command that exits with a non-zero status.

       fc [-e editor | -l [-n]] [-r] [first [last]]
              first and last select commands from the history.   Commands  can
              be  selected  by history number, or a string specifying the most
              recent command starting with that string.  The -l  option  lists
              the  command  on  stdout,  and  -n  inhibits the default command
              numbers.  The -r option reverses the order of the list.  Without
              -l,  the  selected  commands  are edited by the editor specified
              with the -e option,  or  if  no  -e  is  specified,  the  editor
              specified by the FCEDIT parameter (if this parameter is not set,
              /bin/ed is used), and then executed by the shell.

       fc [-e - | -s] [-g] [old=new] [prefix]
              Re-execute  the  selected  command  (the  previous  command   by
              default)  after performing the optional substitution of old with
              new.  If -g is specified, all occurrences of  old  are  replaced
              with  new.  This command is usually accessed with the predefined
              alias r='fc -e -'.

       fg [job ...]
              Resume the specified job(s) in the foreground.  If no  jobs  are
              specified,  %+  is  assumed.   This command is only available on
              systems which support job control.  See Job  Control  below  for
              more information.

       getopts optstring name [arg ...]
              getopts  is  used  by  shell  procedures  to parse the specified
              arguments (or positional parameters, if no arguments are  given)
              and  to  check for legal options.  optstring contains the option
              letters that getopts is to recognize.  If a letter  is  followed
              by a colon, the option is expected to have an argument.  Options
              that do not take arguments may be grouped in a single  argument.
              If  an  option takes an argument and the option character is not
              the last character of the argument it is found in, the remainder
              of the argument is taken to be the option's argument, otherwise,
              the next argument is the option's argument.

              Each time getopts is invoked, it places the next option  in  the
              shell  parameter  name  and the index of the next argument to be
              processed in the shell parameter  OPTIND.   If  the  option  was
              introduced  with a +, the option placed in name is prefixed with
              a +.  When an option requires an argument, getopts places it  in
              the shell parameter OPTARG.  When an illegal option or a missing
              option argument is encountered a question mark  or  a  colon  is
              placed   in  name  (indicating  an  illegal  option  or  missing
              argument,  respectively)  and  OPTARG  is  set  to  the   option
              character  that  caused  the  problem.  An error message is also
              printed to standard error if optstring does  not  begin  with  a
              colon.

              When the end of the options is encountered, getopts exits with a
              non-zero exit status.  Options  end  at  the  first  (non-option
              argument)  argument  that  does not start with a -, or when a --
              argument is encountered.

              Option parsing can be reset by setting OPTIND to 1 (this is done
              automatically  whenever  the  shell  or  a  shell  procedure  is
              invoked).

              Warning: Changing the value of the shell parameter OPTIND  to  a
              value  other  than  1,  or  parsing  different sets of arguments
              without resetting OPTIND may lead to unexpected results.

       hash [-r] [name ...]
              Without arguments, any hashed executable command  pathnames  are
              listed.   The -r option causes all hashed commands to be removed
              from the hash table.  Each name is searched as  if  it  where  a
              command  name and added to the hash table if it is an executable
              command.

       jobs [-lpn] [job ...]
              Display information about the specified jobs;  if  no  jobs  are
              specified,  all  jobs  are  displayed.   The  -n  option  causes
              information to be displayed only  for  jobs  that  have  changed
              state  since  the  last notification.  If the -l option is used,
              the process-id of each process in a job is also listed.  The  -p
              option  causes only the process group of each job to be printed.
              See Job Control below for the format of job  and  the  displayed
              job.

       kill [-s signame | -signum | -signame ] { job | pid | -pgrp } ...
              Send the specified signal to the specified jobs, process ids, or
              process groups.  If no signal is specified, the signal  TERM  is
              sent.   If  a  job is specified, the signal is sent to the job's
              process group.  See Job Control below for the format of job.

       kill -l [exit-status ...]
              Print the name of the signal that killed a process which  exited
              with   the   specified   exit-statuses.   If  no  arguments  are
              specified, a list of all the signals, their numbers and a  short
              description of them are printed.

       let [expression ...]
              Each  expression is evaluated, see Arithmetic Expressions above.
              If all expressions are successfully evaluated, the  exit  status
              is  0  (1)  if the last expression evaluated to non-zero (zero).
              If an error occurs  during  the  parsing  or  evaluation  of  an
              expression,   the   exit   status  is  greater  than  1.   Since
              expressions may need to be quoted, (( expr )) is syntactic sugar
              for let "expr".

       print [-nprsun | -R [-en]] [argument ...]
              Print  prints its arguments on the standard output, separated by
              spaces, and terminated with a newline.  The -n option suppresses
              the  newline.   By  default,  certain  C escapes are translated.
              These include \b, \f, \n, \r, \t, \v, and \0### (# is  an  octal
              digit, of which there may be 0 to 3).  \c is equivalent to using
              the -n option.  \ expansion may be inhibited with the -r option.
              The  -s  option  prints  to the history file instead of standard
              output, the -u option prints to file descriptor n (n defaults to
              1  if  omitted), and the -p option prints to the co-process (see
              Co-Processes above).

              The -R option is used to emulate, to some degree, the  BSD  echo
              command, which does not process \ sequences unless the -e option
              is given.  As above,  the  -n  option  suppresses  the  trailing
              newline.

       pwd [-LP]
              Print the present working directory.  If -L option is used or if
              the physical option (see  set  command  below)  isn't  set,  the
              logical  path  is  printed  (i.e.,  the  path  used to cd to the
              current directory).  If -P option (physical path) is used or  if
              the  physical  option  is  set,  the  path  determined  from the
              filesystem (by following ..  directories to the root  directory)
              is printed.

       read [-prsun] [parameter ...]
              Reads  a  line  of  input from standard input, separate the line
              into fields using the IFS parameter  (see  Substitution  above),
              and assign each field to the specified parameters.  If there are
              more parameters than fields, the extra  parameters  are  set  to
              null,   or   alternatively,   if  there  are  more  fields  than
              parameters, the last parameter is assigned the remaining  fields
              (inclusive  of  any  separating  spaces).   If no parameters are
              specified, the REPLY parameter is used.  If the input line  ends
              in a backslash and the -r option was not used, the backslash and
              newline are stripped and more input is read.   If  no  input  is
              read, read exits with a non-zero status.

              The  first  parameter  may  have  a  question  mark and a string
              appended to it, in which case the string is  used  as  a  prompt
              (printed  to  standard  error  before  any input is read) if the
              input is a tty (e.g., read nfoo?'number of foos: ').

              The -un and  -p  options  cause  input  to  be  read  from  file
              descriptor  n  or the current co-process (see Co-Processes above
              for comments on this), respectively.  If the -s option is  used,
              input is saved to the history file.

       readonly [-p] [parameter[=value]] ...
              Sets  the readonly attribute of the named parameters.  If values
              are given,  parameters  are  set  to  them  before  setting  the
              attribute.   Once  a  parameter  is  made readonly, it cannot be
              unset and its value cannot be changed.

              If no parameters are specified, the names of all parameters with
              the  readonly  attribute are printed one per line, unless the -p
              option is used, in which case  readonly  commands  defining  all
              readonly parameters, including their values, are printed.

       return [status]
              Returns  from  a  function or . script, with exit status status.
              If no status is given, the exit  status  of  the  last  executed
              command  is used.  If used outside of a function or . script, it
              has the same effect  as  exit.   Note  that  pdksh  treats  both
              profile  and  $ENV  files  as . scripts, while the original Korn
              shell only treats profiles as . scripts.

       set [+-abCefhkmnpsuvxX] [+-o [option]] [+-A name] [--] [arg ...]
              The set command can be used  to  set  (-)  or  clear  (+)  shell
              options,   set  the  positional  parameters,  or  set  an  array
              parameter.  Options can be changed using the +-o option  syntax,
              where  option  is  the  long  name  of  an  option, or using the
              +-letter syntax, where letter is the option's single letter name
              (not  all  options  have  a  single letter name).  The following
              table lists both option letters (if they exist) and  long  names
              along with a description of what the option does.

               -A                               Sets the elements of the array
                                                parameter name to arg ...;  If
                                                -A is used, the array is reset
                                                (i.e., emptied) first;  if  +A
                                                is  used, the first N elements
                                                are set (where N is the number
                                                of  args),  the  rest are left
                                                untouched.
               -a         allexport             all new parameters are created
                                                with the export attribute
               -b         notify                Print     job     notification
                                                messages       asynchronously,
                                                instead  of  just  before  the
                                                prompt.   Only  used  if   job
                                                control is enabled (-m).
               -C         noclobber             Prevent   >  redirection  from
                                                overwriting existing files (>|
                                                must   be  used  to  force  an
                                                overwrite).
               -e         errexit               Exit (after executing the  ERR
                                                trap)  as  soon  as  an  error
                                                occurs  or  a  command   fails
                                                (i.e.,  exits  with a non-zero
                                                status).  This does not  apply
                                                to  commands whose exit status
                                                is  explicitly  tested  by   a
                                                shell  construct  such  as if,
                                                until,   while,   &&   or   ||
                                                statements.
               -f         noglob                Do   not   expand   file  name
                                                patterns.
               -h         trackall              Create tracked aliases for all
                                                executed commands (see Aliases
                                                above).   On  by  default  for
                                                non-interactive shells.
               -i         interactive           Enable interactive mode - this
                                                can only be set/unset when the
                                                shell is invoked.
               -k         keyword               Parameter    assignments   are
                                                recognized   anywhere   in   a
                                                command.
               -l         login                 The  shell  is a login shell -
                                                this  can  only  be  set/unset
                                                when the shell is invoked (see
                                                Shell Startup above).
               -m         monitor               Enable  job  control  (default
                                                for interactive shells).

               -n         noexec                Do  not execute any commands -
                                                useful for checking the syntax
                                                of    scripts    (ignored   if
                                                interactive).
               -p         privileged            Set automatically if, when the
                                                shell  starts, the read uid or
                                                gid   does   not   match   the
                                                effective    uid    or    gid,
                                                respectively.     See    Shell
                                                Startup     above     for    a
                                                description   of   what   this
                                                means.
               -r         restricted            Enable restricted mode -- this
                                                option can only be  used  when
                                                the  shell  is  invoked.   See
                                                Shell  Startup  above  for   a
                                                description   of   what   this
                                                means.
               -s         stdin                 If  used  when  the  shell  is
                                                invoked,   commands  are  read
                                                from  standard   input.    Set
                                                automatically  if the shell is
                                                invoked with no arguments.

                                                When -s is  used  in  the  set
                                                command,    it    causes   the
                                                specified  arguments   to   be
                                                sorted  before  assigning them
                                                to the  positional  parameters
                                                (or  to  array  name, if -A is
                                                used).
               -u         nounset               Referencing   of   an    unset
                                                parameter  is  treated  as  an
                                                error, unless one of the -,  +
                                                or = modifiers is used.
               -v         verbose               Write  shell input to standard
                                                error as it is read.
               -x         xtrace                Print commands  and  parameter
                                                assignments   when   they  are
                                                executed,  preceded   by   the
                                                value of PS4.
               -X         markdirs              Mark    directories   with   a
                                                trailing /  during  file  name
                                                generation.
                          bgnice                Background  jobs  are run with
                                                lower priority.
                          braceexpand           Enable brace  expansion  (aka,
                                                alternation).
                          emacs                 Enable  BRL emacs-like command
                                                line   editing    (interactive
                                                shells    only);   see   Emacs
                                                Editing Mode.
                          gmacs                 Enable   gmacs-like   (Gosling
                                                emacs)  command  line  editing
                                                (interactive   shells   only);
                                                currently  identical  to emacs
                                                editing except that  transpose
                                                (^T)       acts       slightly
                                                differently.
                          ignoreeof             The shell  will  not  (easily)
                                                exit  on  when  end-of-file is
                                                read, exit must be  used.   To
                                                avoid   infinite   loops,  the
                                                shell will exit if eof is read
                                                13 times in a row.
                          nohup                 Do  not kill running jobs with
                                                a  HUP  signal  when  a  login
                                                shell  exists.   Currently set
                                                by  default,  but  this   will
                                                change  in  the  future  to be
                                                compatible with  the  original
                                                Korn shell (which doesn't have
                                                this option, but does send the
                                                HUP signal).

                          nolog                 No  effect  -  in the original
                                                Korn  shell,   this   prevents
                                                function    definitions   from
                                                being stored  in  the  history
                                                file.
                          physical              Causes the cd and pwd commands
                                                to use `physical'  (i.e.,  the
                                                filesystem's)  ..  directories
                                                instead      of      `logical'
                                                directories  (i.e.,  the shell
                                                handles .., which  allows  the
                                                user   to   be   oblivious  of
                                                symlink links to directories).
                                                Clear  by  default.  Note that
                                                setting this option  does  not
                                                effect  the  current  value of
                                                the PWD parameter; only the cd
                                                command  changes PWD.  See the
                                                cd and pwd commands above  for
                                                more details.
                          posix                 Enable  posix mode.  See POSIX
                                                Mode above.
                          sh                    This option is set  only  when
                                                ksh  was  called as a standard
                                                /bin/sh  shell.   (Note:  This
                                                option is a Debian and OpenBSD
                                                addition).
                          vi                    Enable  vi-like  command  line
                                                editing   (interactive  shells
                                                only).
                          viraw                 No effect -  in  the  original
                                                Korn  shell,  unless viraw was
                                                set, the vi command line  mode
                                                would  let  the  tty driver do
                                                the work until  ESC  (^[)  was
                                                entered.   pdksh  is always in
                                                viraw mode.
                          vi-esccomplete        In vi command line editing, do
                                                command / file name completion
                                                when escape (^[) is entered in
                                                command mode.
                          vi-show8              Prefix   characters  with  the
                                                eighth bit set with `M-'.   If
                                                this   option   is   not  set,
                                                characters   in   the    range
                                                128-160  are  printed  as  is,
                                                which may cause problems.
                          vi-tabcomplete        In vi command line editing, do
                                                command / file name completion
                                                when tab (^I)  is  entered  in
                                                insert mode.

              These  options  can  also  be used upon invocation of the shell.
              The current set of options (with single  letter  names)  can  be
              found  in the parameter -.  set -o with no option name will list
              all the options and whether each is on or off; set +o will print
              the long names of all options that are currently on.

              Remaining  arguments,  if any, are positional parameters and are
              assigned, in order, to the positional parameters  (i.e.,  1,  2,
              etc.).   If options are ended with -- and there are no remaining
              arguments, all positional parameters are cleared.  If no options
              or  arguments  are  given,  then  the  values  of  all names are
              printed.  For unknown historical reasons, a  lone  -  option  is
              treated specially: it clears both the -x and -v options.

       shift [number]
              The positional parameters number+1, number+2 etc. are renamed to
              1, 2, etc.  number defaults to 1.

       test expression

       [ expression ]
              test evaluates the expression and returns zero status  if  true,
              and  1 status if false and greater than 1 if there was an error.
              It is normally used as the condition command  of  if  and  while
              statements.  The following basic expressions are available:

               str                  str   has  non-zero  length.
                                    Note  that  there   is   the
                                    potential  for  problems  if
                                    str  turns  out  to  be   an
                                    operator  (e.g., -r) - it is
                                    generally better  to  use  a
                                    test like
                                                  [  X"str" != X
                                                  ]
                                           instead       (double
                                           quotes  are  used  in
                                           case   str   contains
                                           spaces     or    file
                                           globing characters).
               -r file              file exists and is readable.
               -w file              file exists and is writable.
               -x file              file    exists    and     is
                                    executable.
               -a file              file exists.
               -e file              file exists.
               -f file              file is a regular file.
               -d file              file is a directory.
               -c file              file  is a character special
                                    device.
               -b file              file  is  a  block   special
                                    device.
               -p file              file is a named pipe.
               -u file              file's  mode  has setuid bit
                                    set.
               -g file              file's mode has  setgid  bit
                                    set.
               -k file              file's  mode  has sticky bit
                                    set.
               -s file              file is not empty.
               -O file              file's owner is the  shell's
                                    effective user-ID.
               -G file              file's  group is the shell's
                                    effective group-ID.
               -h file              file is a symbolic link.
               -H file              file is a context  dependent
                                    directory  (only  useful  on
                                    HP-UX).
               -L file              file is a symbolic link.
               -S file              file is a socket.
               -o option            shell option is set (see set
                                    command  above  for  list of
                                    options).  As a non-standard
                                    extension,   if  the  option
                                    starts with a !, the test is
                                    negated;   the  test  always
                                    fails  if   option   doesn't
                                    exist (thus
                                                  [ -o foo -o -o
                                                  !foo ]
                                           returns true  if  and
                                           only  if  option  foo
                                           exists).
               file -nt file        first  file  is  newer  than
                                    second  file  or  first file
                                    exists and the  second  file
                                    does not.
               file -ot file        first  file  is  older  than
                                    second file or  second  file
                                    exists  and  the  first file
                                    does not.
               file -ef file        first file is the same  file
                                    as second file.

               -t [fd]              file  descriptor  is  a  tty
                                    device.  If the posix option
                                    (set  -o  posix,  see  POSIX
                                    Mode above) is not  set,  fd
                                    may  be  left  out, in which
                                    case it is  taken  to  be  1
                                    (the  behaviour  differs due
                                    to the special  POSIX  rules
                                    described below).
               string               string is not empty.
               -z string            string is empty.
               -n string            string is not empty.
               string = string      strings are equal.
               string == string     strings are equal.
               string != string     strings are not equal.
               number -eq number    numbers compare equal.
               number -ne number    numbers compare not equal.
               number -ge number    numbers compare greater than
                                    or equal.
               number -gt number    numbers   compare    greater
                                    than.
               number -le number    numbers compare less than or
                                    equal.
               number -lt number    numbers compare less than.

              The above basic  expressions,  in  which  unary  operators  have
              precedence  over  binary  operators,  may  be  combined with the
              following operators (listed in increasing order of precedence):

               expr -o expr    logical or
               expr -a expr    logical and
               ! expr          logical not
               ( expr )        grouping

              On operating systems not supporting /dev/fd/n devices  (where  n
              is  a  file descriptor number), the test command will attempt to
              fake it for all tests that  operate  on  files  (except  the  -e
              test).   I.e.,  [  -w  /dev/fd/2 ] tests if file descriptor 2 is
              writable.

              Note that some special rules are applied (courtesy of POSIX)  if
              the number of arguments to test or [ ... ] is less than five: if
              leading ! arguments can be stripped such that only one  argument
              remains  then  a string length test is performed (again, even if
              the argument is a unary operator); if leading ! arguments can be
              stripped  such  that  three  arguments  remain  and  the  second
              argument is a binary operator,  then  the  binary  operation  is
              performed (even if first argument is a unary operator, including
              an unstripped !).

              Note: A common mistake is to use if [ $foo = bar ]  which  fails
              if  parameter  foo  is  null or unset, if it has embedded spaces
              (i.e., IFS characters), or if it is a unary operator like  !  or
              -n.  Use tests like if [ "X$foo" = Xbar ] instead.

       time [-p] [ pipeline ]
              If  a  pipeline is given, the times used to execute the pipeline
              are reported.  If no pipeline is given, then the user and system
              time  used  by the shell itself, and all the commands it has run
              since it was started, are reported.  The times reported are  the
              real time (elapsed time from start to finish), the user cpu time
              (time spent running in user mode) and the system cpu time  (time
              spent  running  in kernel mode).  Times are reported to standard
              error; the format of the output is:
                  0.00s real     0.00s user     0.00s system
              unless the -p option is given (only possible if  pipeline  is  a
              simple command), in which case the output is slightly longer:
                  real   0.00
                  user   0.00
                  sys    0.00
              (the  number of digits after the decimal may vary from system to
              system).  Note that simple redirections of standard error do not
              effect the output of the time command:
                                   time sleep 1 2> afile
                                 { time sleep 1; } 2> afile
              times for the first command do not go to afile, but those of the
              second command do.

       times  Print the accumulated user and system times used  by  the  shell
              and by processes which have exited that the shell started.

       trap [handler signal ...]
              Sets  trap  handler  that  is  to  be  executed  when any of the
              specified signals  are  received.   Handler  is  either  a  null
              string,  indicating  the signals are to be ignored, a minus (-),
              indicating that the default  action  is  to  be  taken  for  the
              signals  (see  signal(2)), or a string containing shell commands
              to be evaluated and executed at  the  first  opportunity  (i.e.,
              when  the current command completes, or before printing the next
              PS1 prompt) after receipt of one of the signals.  Signal is  the
              name  of  a  signal  (e.g.,  PIPE  or ALRM) or the number of the
              signal (see kill -l  command  above).   There  are  two  special
              signals:  EXIT  (also  known  as  0), which is executed when the
              shell is about to exit, and ERR which is executed after an error
              occurs (an error is something that would cause the shell to exit
              if the -e or errexit option were set -- see set command  above).
              EXIT  handlers  are  executed  in  the  environment  of the last
              executed command.  Note that  for  non-interactive  shells,  the
              trap  handler  cannot  be  changed for signals that were ignored
              when the shell started.

              With no arguments, trap lists, as a series of trap commands, the
              current  state  of  the traps that have been set since the shell
              started.  Note that the output of trap can not be usefully piped
              to  another  process  (an  artifact  of  the fact that traps are
              cleared when subprocesses are created).

              The original Korn shell's DEBUG trap and the handling of ERR and
              EXIT traps in functions are not yet implemented.

       true   A command that exits with a zero value.

       typeset  [[+-Ulprtux]  [-L[n]]  [-R[n]]  [-Z[n]]  [-i[n]]  | -f [-tux]]
       [name[=value] ...]
              Display or set parameter attributes.  With  no  name  arguments,
              parameter  attributes are displayed: if no options arg used, the
              current attributes of all  parameters  are  printed  as  typeset
              commands; if an option is given (or - with no option letter) all
              parameters and their values with the  specified  attributes  are
              printed;  if options are introduced with +, parameter values are
              not printed.

              If name  arguments  are  given,  the  attributes  of  the  named
              parameters  are  set  (-) or cleared (+).  Values for parameters
              may optionally be  specified.   If  typeset  is  used  inside  a
              function,   any  newly  created  parameters  are  local  to  the
              function.

              When  -f  is  used,  typeset  operates  on  the  attributes   of
              functions.  As with parameters, if no names are given, functions
              are listed with their values (i.e., definitions) unless  options
              are introduced with +, in which case only the function names are
              reported.

               -Ln               Left justify attribute: n specifies the field
                                 width.   If  n  is not specified, the current
                                 width of a parameter (or  the  width  of  its
                                 first assigned value) is used.  Leading white
                                 space (and zeros, if used with the -Z option)
                                 is stripped.  If necessary, values are either
                                 truncated or space padded to  fit  the  field
                                 width.

               -Rn               Right  justify  attribute:  n  specifies  the
                                 field width.  If  n  is  not  specified,  the
                                 current width of a parameter (or the width of
                                 its first assigned value) is used.   Trailing
                                 white  space  are  stripped.   If  necessary,
                                 values  are  either   stripped   of   leading
                                 characters  or  space padded to make them fit
                                 the field width.
               -Zn               Zero fill attribute: if not combined with -L,
                                 this  is  the same as -R, except zero padding
                                 is used instead of space padding.
               -in               integer attribute: n specifies  the  base  to
                                 use  when  displaying  the  integer  (if  not
                                 specified,  the  base  given  in  the   first
                                 assignment  is  used).   Parameters with this
                                 attribute may be assigned  values  containing
                                 arithmetic expressions.
               -U                unsigned   integer  attribute:  integers  are
                                 printed as unsigned values (only useful  when
                                 combined with the -i option).  This option is
                                 not in the original Korn shell.
               -f                Function mode: display or set  functions  and
                                 their attributes, instead of parameters.
               -l                Lower   case   attribute:   all   upper  case
                                 characters in values are converted  to  lower
                                 case.   (In  the  original  Korn  shell, this
                                 parameter meant `long integer' when used with
                                 the -i option).
               -p                Print  complete  typeset commands that can be
                                 used to re-create the attributes (but not the
                                 values)  of  parameters.  This is the default
                                 action    (option    exists     for     ksh93
                                 compatibility).
               -r                Readonly  attribute: parameters with the this
                                 attribute may not be assigned  to  or  unset.
                                 Once  this  attribute  is  set, it can not be
                                 turned off.
               -t                Tag attribute: has no meaning to  the  shell;
                                 provided for application use.

                                 For  functions,  -t  is  the trace attribute.
                                 When functions with the trace  attribute  are
                                 executed,  the  xtrace  (-x)  shell option is
                                 temporarily turned on.
               -u                Upper  case   attribute:   all   lower   case
                                 characters  in  values are converted to upper
                                 case.  (In  the  original  Korn  shell,  this
                                 parameter  meant `unsigned integer' when used
                                 with the -i option, which  meant  upper  case
                                 letters would never be used for bases greater
                                 than 10.  See the -U option).

                                 For functions, -u is the undefined attribute.
                                 See  Functions  above for the implications of
                                 this.
               -x                Export attribute: parameters  (or  functions)
                                 are placed in the environment of any executed
                                 commands.    Exported   functions   are   not
                                 implemented yet.

       ulimit [-acdfHlmnpsStvwL] [value]
              Display or set process limits.  If no options are used, the file
              size limit (-f) is assumed.  value, if specified, may be  either
              be  an  arithmetic expression or the word unlimited.  The limits
              affect the shell and any processes created by the shell after  a
              limit  is  imposed.  Note that some systems may not allow limits
              to be increased once they are set.  Also note that the types  of
              limits  available  are system dependent - some systems have only
              the -f limit.

              -a     Displays all limits; unless -H is used, soft  limits  are
                     displayed.

              -H     Set  the hard limit only (default is to set both hard and
                     soft limits).

              -S     Set the soft limit only (default is to set both hard  and
                     soft limits).

              -c     Impose  a  size  limit  of  n  blocks on the size of core
                     dumps.

              -d     Impose a size limit of n kbytes on the size of  the  data
                     area.

              -f     Impose  a  size limit of n blocks on files written by the
                     shell and its child processes (files of any size  may  be
                     read).

              -l     Impose  a  limit  of  n  kbytes  on  the amount of locked
                     (wired) physical memory.

              -m     Impose a limit of n kbytes  on  the  amount  of  physical
                     memory used.

              -n     Impose  a limit of n file descriptors that can be open at
                     once.

              -p     Impose a limit of n processes that can be run by the user
                     at any one time.

              -s     Impose  a size limit of n kbytes on the size of the stack
                     area.

              -t     Impose a time limit of n cpu seconds to be used  by  each
                     process.

              -v     Impose  a  limit  of  n  kbytes  on the amount of virtual
                     memory  used;  on  some  systems  this  is  the   maximum
                     allowable virtual address (in bytes, not kbytes).

              -w     Impose  a  limit  of n kbytes on the amount of swap space
                     used.

              -L     Impose a limit of n locks that can be held on files.

              As far as ulimit is concerned, a block is 512 bytes.

       umask [-S] [mask]
              Display or set the file permission creation mask, or umask  (see
              umask(2)).   If the -S option is used, the mask displayed or set
              is symbolic, otherwise it is an octal number.

              Symbolic masks are like those used by chmod(1):
                     [ugoa]{{=+-}{rwx}*}+[,...]
              in which the first group of characters  is  the  who  part,  the
              second  group  is  the  op  part, and the last group is the perm
              part.  The who part specifies which part of the umask is  to  be
              modified.  The letters mean:

                     u      the user permissions

                     g      the group permissions

                     o      the other permissions (non-user, non-group)

                     a      all permissions (user, group and other)

              The  op  part  indicates  how  the  who  permissions  are  to be
              modified:

                     =      set

                     +      added to

                     -      removed from

              The perm part specifies which permissions are to be  set,  added
              or removed:

                     r      read permission

                     w      write permission

                     x      execute permission

              When symbolic masks are used, they describe what permissions may
              be made available (as opposed to octal masks in which a set  bit
              means  the  corresponding  bit  is  to  be  cleared).   Example:
              `ug=rwx,o=' sets  the  mask  so  files  will  not  be  readable,
              writable  or  executable by `others', and is equivalent (on most
              systems) to the octal mask `07'.

       unalias [-adt] [name1 ...]
              The aliases for the given names are removed.  If the  -a  option
              is  used,  all aliases are removed.  If the -t or -d options are
              used, the indicated operations are carried  out  on  tracked  or
              directory aliases, respectively.

       unset [-fv] parameter ...
              Unset  the named parameters (-v, the default) or functions (-f).
              The exit status is  non-zero  if  any  of  the  parameters  were
              already unset, zero otherwise.

       wait [job]
              Wait  for  the  specified  job(s) to finish.  The exit status of
              wait is that of the last specified  job:  if  the  last  job  is
              killed  by  a signal, the exit status is 128 + the number of the
              signal (see kill -l exit-status above); if  the  last  specified
              job  can't  be  found  (because it never existed, or had already
              finished), the exit status of wait  is  127.   See  Job  Control
              below  for  the format of job.  Wait will return if a signal for
              which a trap has been set is received, or if a HUP, INT or  QUIT
              signal is received.

              If  no  jobs are specified, wait waits for all currently running
              jobs (if any) to finish and exits with a zero  status.   If  job
              monitoring  is enabled, the completion status of jobs is printed
              (this is not the case when jobs are explicitly specified).

       whence [-pv] [name ...]
              For each name, the type of command  is  listed  (reserved  word,
              built-in, alias, function, tracked alias or executable).  If the
              -p option is used, a path search done even if name is a reserved
              word,  alias,  etc.  Without the -v option, whence is similar to
              command -v except that whence will find reserved words and won't
              print  aliases  as alias commands; with the -v option, whence is
              the same as command -V.  Note that for  whence,  the  -p  option
              does  not  affect  the search path used, as it does for command.
              If the type of one or more of the names could not be determined,
              the exit status is non-zero.

   Job Control
       Job  control refers to the shell's ability to monitor and control jobs,
       which are processes or groups of  processes  created  for  commands  or
       pipelines.   At  a  minimum, the shell keeps track of the status of the
       background  (i.e.,  asynchronous)  jobs  that  currently  exist;   this
       information can be displayed using the jobs command.  If job control is
       fully enabled  (using  set  -m  or  set  -o  monitor),  as  it  is  for
       interactive  shells,  the  processes  of  a job are placed in their own
       process group, foreground jobs can be stopped  by  typing  the  suspend
       character  from  the  terminal  (normally ^Z), jobs can be restarted in
       either the foreground or background, using  the  fg  and  bg  commands,
       respectively, and the state of the terminal is saved or restored when a
       foreground job is stopped or restarted, respectively.

       Note that only  commands  that  create  processes  (e.g.,  asynchronous
       commands,  subshell  commands, and non-built-in, non-function commands)
       can be stopped; commands like read cannot be.

       When a job is created, it is assigned a  job-number.   For  interactive
       shells, this number is printed inside [..], followed by the process-ids
       of the processes in the job when an asynchronous command is run.  A job
       may  be  referred  to in bg, fg, jobs, kill and wait commands either by
       the process id of the last process in the command pipeline  (as  stored
       in the $! parameter) or by prefixing the job-number with a percent sign
       (%).  Other percent sequences can also be used to refer to jobs:

        %+                       The most recently stopped job, or,  if  there
                                 are no stopped jobs, the oldest running job.
        %%, %                    Same as %+.
        %-                       The  job  that  would  be  the %+ job, if the
                                 later did not exist.
        %n                       The job with job-number n.
        %?string                 The job  containing  the  string  string  (an
                                 error occurs if multiple jobs are matched).
        %string                  The job starting with string string (an error
                                 occurs if multiple jobs are matched).

       When a job changes state (e.g., a background job finishes or foreground
       job is stopped), the shell prints the following status information:
              [number] flag status command
       where

        number
              is the job-number of the job.

        flag  is + or - if the job is the %+ or %- job, respectively, or space
              if it is neither.

        status
              indicates the current state of the job and can be

              Running
                     the job has neither stopped or exited (note that  running
                     does  not  necessarily  mean  consuming  CPU  time -- the
                     process could be blocked waiting for some event).

              Done [(number)]
                     the job exited. number is the exit  status  of  the  job,
                     which is omitted if the status is zero.

              Stopped [(signal)]
                     the job was stopped by the indicated signal (if no signal
                     is given, the job was stopped by SIGTSTP).

              signal-description [(core dumped)]
                     the job was  killed  by  a  signal  (e.g.,  Memory fault,
                     Hangup,  etc.  --  use  kill  -l  for  a  list  of signal
                     descriptions).  The (core dumped) message  indicates  the
                     process created a core file.

        command
              is  the command that created the process.  If there are multiple
              processes in the job, then each process will have a line showing
              its command and possibly its status, if it is different from the
              status of the previous process.

       When an attempt is made to exit the shell while there are jobs  in  the
       stopped state, the shell warns the user that there are stopped jobs and
       does not exit.  If another attempt is  immediately  made  to  exit  the
       shell,  the  stopped  jobs  are  sent a HUP signal and the shell exits.
       Similarly, if the nohup option is not set and there  are  running  jobs
       when an attempt is made to exit a login shell, the shell warns the user
       and does not exit.  If another attempt is immediately made to exit  the
       shell, the running jobs are sent a HUP signal and the shell exits.

   Interactive Input Line Editing
       The  shell  supports three modes of reading command lines from a tty in
       an interactive session.  Which is used  is  controlled  by  the  emacs,
       gmacs and vi set options (at most one of these can be set at once).  If
       none of these options is enabled, the shell simply  reads  lines  using
       the  normal tty driver.  If the emacs or gmacs option is set, the shell
       allows emacs like editing of the command; similarly, if the  vi  option
       is  set,  the shell allows vi like editing of the command.  These modes
       are described in detail in the following sections.

       In these editing modes, if a line is longer that the screen width  (see
       COLUMNS  parameter),  a  >,  +  or < character is displayed in the last
       column indicating that there are  more  characters  after,  before  and
       after,  or  before  the  current  position,  respectively.  The line is
       scrolled horizontally as necessary.

   Emacs Editing Mode
       When the emacs  option  is  set,  interactive  input  line  editing  is
       enabled.   Warning: This mode is slightly different from the emacs mode
       in the original Korn shell and the 8th bit is stripped in  emacs  mode.
       In  this  mode various editing commands (typically bound to one or more
       control characters) cause immediate actions without waiting for a  new-
       line.   Several  editing  commands  are  bound  to  particular  control
       characters when the shell is invoked; these  bindings  can  be  changed
       using the following commands:

       bind   The current bindings are listed.

       bind string=[editing-command]
              The  specified  editing  command  is  bound to the given string,
              which should consist  of  a  control  character  (which  may  be
              written  using caret notation ^X), optionally preceded by one of
              the two prefix characters.  Future  input  of  the  string  will
              cause  the editing command to be immediately invoked.  Note that
              although only two prefix characters (usually  ESC  and  ^X)  are
              supported, some multi-character sequences can be supported.  The
              following binds the arrow keys on an  ANSI  terminal,  or  xterm
              (these  are  in  the  default  bindings).  Of course some escape
              sequences won't work out quite this nicely:

              bind '^[['=prefix-2
              bind '^XA'=up-history
              bind '^XB'=down-history
              bind '^XC'=forward-char
              bind '^XD'=backward-char

       bind -l
              Lists the names of the functions to which keys may be bound.

       bind -m string=[substitute]
              The  specified  input  string  will  afterwards  be  immediately
              replaced  by  the  given  substitute  string,  which may contain
              editing commands.

       The  following  is  a  list  of  editing  commands   available.    Each
       description  starts  with  the name of the command, a n, if the command
       can be prefixed with a count, and any keys the command is bound  to  by
       default  (written  using  caret  notation, e.g., ASCII ESC character is
       written as ^[).  A count prefix for a  command  is  entered  using  the
       sequence  ^[n,  where  n  is  a  sequence  of  1 or more digits; unless
       otherwise specified, if a count is omitted, it  defaults  to  1.   Note
       that  editing  command  names  are  used  only  with  the bind command.
       Furthermore, many editing commands are useful only on terminals with  a
       visible   cursor.    The  default  bindings  were  chosen  to  resemble
       corresponding EMACS key bindings.   The  users  tty  characters  (e.g.,
       ERASE)  are  bound  to  reasonable substitutes and override the default
       bindings.

       abort ^G
              Useful as a response to a request for a  search-history  pattern
              in order to abort the search.

       auto-insert n
              Simply  causes  the  character to appear as literal input.  Most
              ordinary characters are bound to this.

       backward-char  n ^B
              Moves the cursor backward n characters.

       backward-word  n ^[B
              Moves the cursor backward to the  beginning  of  a  word;  words
              consist of alphanumerics, underscore (_) and dollar ($).

       beginning-of-history ^[<
              Moves to the beginning of the history.

       beginning-of-line ^A
              Moves the cursor to the beginning of the edited input line.

       capitalize-word n ^[c, ^[C
              Uppercase  the  first character in the next n words, leaving the
              cursor past the end of the last word.  If the current line  does
              not  begin  with  a  comment  character,  one  is  added  at the
              beginning of the line and the line is entered (as if return  had
              been  pressed),  otherwise  the  existing comment characters are
              removed and the cursor is placed at the beginning of the line.

       complete ^[^[
              Automatically completes as much as is unique of the command name
              or the file name containing the cursor.  If the entire remaining
              command or file name is unique a  space  is  printed  after  its
              completion,  unless  it  is  a directory name in which case / is
              appended.  If there is no command or file name with the  current
              partial  word as its prefix, a bell character is output (usually
              causing a audio beep).

       complete-command ^X^[
              Automatically completes as much as is unique of the command name
              having  the  partial  word up to the cursor as its prefix, as in
              the complete command described above.

       complete-file ^[^X
              Automatically completes as much as is unique of  the  file  name
              having  the  partial  word up to the cursor as its prefix, as in
              the complete command described above.

       complete-list ^[=
              List the possible completions for the current word.

       delete-char-backward n ERASE, ^?, ^H
              Deletes n characters before the cursor.

       delete-char-forward n
              Deletes n characters after the cursor.

       delete-word-backward n ^[ERASE, ^[^?, ^[^H, ^[h
              Deletes n words before the cursor.

       delete-word-forward n ^[d
              Deletes characters after the cursor up to the end of n words.

       down-history n ^N
              Scrolls the history buffer forward n lines (later).  Each  input
              line  originally starts just after the last entry in the history
              buffer, so down-history  is  not  useful  until  either  search-
              history or up-history has been performed.

       downcase-word n ^[L, ^[l
              Lowercases the next n words.

       end-of-history ^[>
              Moves to the end of the history.

       end-of-line ^E
              Moves the cursor to the end of the input line.

       eot ^_ Acts  as  an end-of-file; this is useful because edit-mode input
              disables normal terminal input canonicalization.

       eot-or-delete n ^D
              Acts as eot if alone on a line; otherwise acts  as  delete-char-
              forward.

       error  Error (ring the bell).

       exchange-point-and-mark ^X^X
              Places  the cursor where the mark is, and sets the mark to where
              the cursor was.

       expand-file ^[*
              Appends a * to the current word and replaces the word  with  the
              result  of  performing  file  globbing on the word.  If no files
              match the pattern, the bell is rung.

       forward-char n ^F
              Moves the cursor forward n characters.

       forward-word n ^[f
              Moves the cursor forward to the end of the nth word.

       goto-history n ^[g
              Goes to history number n.

       kill-line KILL
              Deletes the entire input line.

       kill-region ^W
              Deletes the input between the cursor and the mark.

       kill-to-eol n ^K
              Deletes the input from the cursor to the end of the line if n is
              not  specified,  otherwise deletes characters between the cursor
              and column n.

       list ^[?
              Prints a sorted, columnated list of command names or file  names
              (if  any)  that  can  complete  the  partial word containing the
              cursor.  Directory names have / appended to them.

       list-command ^X?
              Prints a sorted, columnated list of command names (if any)  that
              can complete the partial word containing the cursor.

       list-file ^X^Y
              Prints a sorted, columnated list of file names (if any) that can
              complete the partial word  containing  the  cursor.   File  type
              indicators are appended as described under list above.

       newline ^J, ^M
              Causes the current input line to be processed by the shell.  The
              current cursor position may be anywhere on the line.

       newline-and-next ^O
              Causes the current input line to be processed by the shell,  and
              the  next  line  from history becomes the current line.  This is
              only useful after an up-history or search-history.

       no-op QUIT
              This does nothing.

       prefix-1 ^[
              Introduces a 2-character command sequence.

       prefix-2 ^X

       prefix-2 ^[[
              Introduces a 2-character command sequence.

       prev-hist-word n ^[., ^[_
              The last (nth) word of the previous command is inserted  at  the
              cursor.

       quote ^^
              The  following  character  is  taken literally rather than as an
              editing command.

       redraw ^L
              Reprints the prompt string and the current input line.

       search-character-backward n ^[^]
              Search backward in the current line for the  nth  occurrence  of
              the next character typed.

       search-character-forward n ^]
              Search forward in the current line for the nth occurrence of the
              next character typed.

       search-history ^R
              Enter incremental search mode.  The  internal  history  list  is
              searched  backwards for commands matching the input.  An initial
              ^ in the search string anchors the search.  The abort  key  will
              leave  search  mode.   Other  commands  will  be  executed after
              leaving  search  mode.    Successive   search-history   commands
              continue  searching  backward to the next previous occurrence of
              the pattern.  The history buffer retains only a finite number of
              lines; the oldest are discarded as necessary.

       set-mark-command ^[<space>
              Set the mark at the cursor position.

       stuff  On  systems  supporting it, pushes the bound character back onto
              the terminal input where it may receive  special  processing  by
              the terminal handler.  This is useful for the BRL ^T mini-systat
              feature, for example.

       stuff-reset
              Acts like stuff, then aborts input the same as an interrupt.

       transpose-chars ^T
              If at the end of line, or if  the  gmacs  option  is  set,  this
              exchanges  the  two previous characters; otherwise, it exchanges
              the previous and current characters and  moves  the  cursor  one
              character to the right.

       up-history n ^P
              Scrolls the history buffer backward n lines (earlier).

       upcase-word n ^[U, ^[u
              Uppercases the next n words.

       version ^V
              Display the version of ksh.  The current edit buffer is restored
              as soon as any key is pressed (the key is then processed, unless
              it is a space).

       yank ^Y
              Inserts  the  most  recently  killed  text string at the current
              cursor position.

       yank-pop ^[y
              Immediately after a yank, replaces the inserted text string with
              the next previous killed text string.

   Vi Editing Mode
       The  vi  command  line editor in ksh has basically the same commands as
       the vi editor (see vi(1)), with the following exceptions:

         o    you start out in insert mode,

         o    there are file name and command completion commands  (=,  \,  *,
              ^X, ^E, ^F and, optionally, <tab>),

         o    the  _  command  is  different  (in  ksh it is the last argument
              command, in vi it goes to the start of the current line),

         o    the / and G commands move in the opposite  direction  as  the  j
              command

         o    and  commands which don't make sense in a single line editor are
              not available (e.g., screen movement commands,  ex  :  commands,
              etc.).

       Note  that  the  ^X stands for control-X; also <esc>, <space> and <tab>
       are used for escape, space and tab, respectively (no kidding).

       Like vi, there are two modes: insert mode and command mode.  In  insert
       mode,  most  characters  are  simply  put  in the buffer at the current
       cursor position as they are typed, however, some characters are treated
       specially.   In  particular,  the  following  characters are taken from
       current tty settings (see stty(1)) and have their usual meaning (normal
       values  are  in  parentheses):  kill (^U), erase (^?), werase (^W), eof
       (^D), intr (^C) and quit (^\).  In addition to the above, the following
       characters are also treated specially in insert mode:

        ^H                       erases previous character
        ^V                       literal next: the next character typed is not
                                 treated specially (can be used to insert  the
                                 characters being described here)
        ^J ^M                    end of line: the current line is read, parsed
                                 and executed by the shell
        <esc>                    puts the editor in command mode (see below)
        ^E                       command and file name enumeration (see below)

        ^F                       command and file name completion (see below).
                                 If  used twice in a row, the list of possible
                                 completions is displayed;  if  used  a  third
                                 time, the completion is undone.
        ^X                       command and file name expansion (see below)
        <tab>                    optional  file  name  and  command completion
                                 (see ^F  above),  enabled  with  set  -o  vi-
                                 tabcomplete

       In   command   mode,  each  character  is  interpreted  as  a  command.
       Characters that don't correspond to commands, are illegal  combinations
       of  commands or are commands that can't be carried out all cause beeps.
       In the following command descriptions, a n indicates the command may be
       prefixed  by  a  number  (e.g.,  10l  moves right 10 characters); if no
       number prefix is used, n is assumed to be 1 unless otherwise specified.
       The  term  `current position' refers to the position between the cursor
       and the character preceding the cursor.  A  `word'  is  a  sequence  of
       letters,  digits and underscore characters or a sequence of non-letter,
       non-digit, non-underscore,  non-white-space  characters  (e.g.,  ab2*&^
       contains  two  words) and a `big-word' is a sequence of non-white-space
       characters.

       Special ksh vi commands
              The following commands are not in, or are  different  from,  the
              normal vi file editor:

              n_     insert a space followed by the nth big-word from the last
                     command in the history at the current position and  enter
                     insert  mode;  if  n  is  not specified, the last word is
                     inserted.

              #      insert the comment character (#)  at  the  start  of  the
                     current line and return the line to the shell (equivalent
                     to I#^J).

              ng     like G, except if n is not specified, it goes to the most
                     recent remembered line.

              nv     edit  line  n using the vi editor; if n is not specified,
                     the current line is edited.  The actual command  executed
                     is `fc -e ${VISUAL:-${EDITOR:-vi}} n'.

              * and ^X
                     command  or file name expansion is applied to the current
                     big-word (with an appended *, if  the  word  contains  no
                     file  globing characters) - the big-word is replaced with
                     the resulting words.  If  the  current  big-word  is  the
                     first  on  the  line  (or  follows  one  of the following
                     characters: ;, |, &, (, )) and does not contain  a  slash
                     (/)  then  command expansion is done, otherwise file name
                     expansion is done.  Command expansion will match the big-
                     word against all aliases, functions and built-in commands
                     as well as any executable files found  by  searching  the
                     directories  in  the PATH parameter.  File name expansion
                     matches the big-word against the  files  in  the  current
                     directory.   After  expansion,  the cursor is placed just
                     past the last word and the editor is in insert mode.

              n\, n^F, n<tab> and n<esc>
                     command/file name completion: replace  the  current  big-
                     word   with  the  longest  unique  match  obtained  after
                     performing command/file name expansion.   <tab>  is  only
                     recognized  if  the  vi-tabcomplete  option is set, while
                     <esc> is only recognized if the vi-esccomplete option  is
                     set  (see  set  -o).  If n is specified, the nth possible
                     completion is selected (as reported by  the  command/file
                     name enumeration command).

              = and ^E
                     command/file  name  enumeration: list all the commands or
                     files that match the current big-word.

              ^V     display the version  of  pdksh;  it  is  displayed  until
                     another key is pressed (this key is ignored).

              @c     macro  expansion: execute the commands found in the alias
                     _c.

       Intra-line movement commands

              nh and n^H
                     move left n characters.

              nl and n<space>
                     move right n characters.

              0      move to column 0.

              ^      move to the first non white-space character.

              n|     move to column n.

              $      move to the last character.

              nb     move back n words.

              nB     move back n big-words.

              ne     move forward to the end the word, n times.

              nE     move forward to the end the big-word, n times.

              nw     move forward n words.

              nW     move forward n big-words.

              %      find match: the editor  looks  forward  for  the  nearest
                     parenthesis,  bracket  or brace and then moves the to the
                     matching parenthesis, bracket or brace.

              nfc    move forward to the nth occurrence of the character c.

              nFc    move backward to the nth occurrence of the character c.

              ntc    move forward to just before the  nth  occurrence  of  the
                     character c.

              nTc    move  backward  to  just before the nth occurrence of the
                     character c.

              n;     repeats the last f, F, t or T command.

              n,     repeats the last f, F, t or T command, but moves  in  the
                     opposite direction.

       Inter-line movement commands

              nj and n+ and n^N
                     move to the nth next line in the history.

              nk and n- and n^P
                     move to the nth previous line in the history.

              nG     move to line n in the history; if n is not specified, the
                     number first remembered line is used.

              ng     like G, except if n is not specified, it goes to the most
                     recent remembered line.

              n/string
                     search  backward  through  the  history  for the nth line
                     containing string; if string starts with ^, the remainder
                     of  the  string  must  appear at the start of the history
                     line for it to match.

              n?string
                     same  as  /,  except  it  searches  forward  through  the
                     history.

              nn     search  for the nth occurrence of the last search string;
                     the direction of the search  is  the  same  as  the  last
                     search.

              nN     search  for the nth occurrence of the last search string;
                     the direction of the search is the opposite of  the  last
                     search.

       Edit commands

              na     append text n times: goes into insert mode just after the
                     current position.   The  append  is  only  replicated  if
                     command mode is re-entered (i.e., <esc> is used).

              nA     same as a, except it appends at the end of the line.

              ni     insert text n times: goes into insert mode at the current
                     position.  The insertion is only  replicated  if  command
                     mode is re-entered (i.e., <esc> is used).

              nI     same  as  i, except the insertion is done just before the
                     first non-blank character.

              ns     substitute  the  next  n  characters  (i.e.,  delete  the
                     characters and go into insert mode).

              S      substitute whole line: all characters from the first non-
                     blank character to the end of line are deleted and insert
                     mode is entered.

              ncmove-cmd
                     change   from   the  current  position  to  the  position
                     resulting from n move-cmds (i.e.,  delete  the  indicated
                     region  and  go  into insert mode); if move-cmd is c, the
                     line starting  from  the  first  non-blank  character  is
                     changed.

              C      change  from  the current position to the end of the line
                     (i.e., delete to the end of the line and go  into  insert
                     mode).

              nx     delete the next n characters.

              nX     delete the previous n characters.

              D      delete to the end of the line.

              ndmove-cmd
                     delete   from   the  current  position  to  the  position
                     resulting  from  n  move-cmds;  move-cmd  is  a  movement
                     command  (see above) or d, in which case the current line
                     is deleted.

              nrc    replace the next n characters with the character c.

              nR     replace:  enter  insert  mode  but   overwrite   existing
                     characters   instead   of   inserting   before   existing
                     characters.  The replacement is repeated n times.

              n~     change the case of the next n characters.

              nymove-cmd
                     yank from the current position to the position  resulting
                     from  n move-cmds into the yank buffer; if move-cmd is y,
                     the whole line is yanked.

              Y      yank from the current position to the end of the line.

              np     paste the contents of the  yank  buffer  just  after  the
                     current position, n times.

              nP     same  as  p,  except  the buffer is pasted at the current
                     position.

       Miscellaneous vi commands

              ^J and ^M
                     the current line is read,  parsed  and  executed  by  the
                     shell.

              ^L and ^R
                     redraw the current line.

              n.     redo the last edit command n times.

              u      undo the last edit command.

              U      undo all changes that have been made to the current line.

              intr and quit
                     the  interrupt  and  quit  terminal  characters cause the
                     current line to  be  deleted  and  a  new  prompt  to  be
                     printed.

FILES

       ~/.profile
       /etc/profile
       /etc/suid_profile

BUGS

       Any  bugs  in  pdksh  should  be  reported  to pdksh@cs.mun.ca.  Please
       include the version of pdksh (echo $KSH_VERSION shows it), the machine,
       operating system and compiler you are using and a description of how to
       repeat the bug (a small shell  script  that  demonstrates  the  bug  is
       best).  The following, if relevant (if you are not sure, include them),
       can also helpful: options you are using (both options.h options and set
       -o  options)  and  a  copy  of your config.h (the file generated by the
       configure  script).   New  versions  of  pdksh  can  be  obtained  from
       ftp://ftp.cs.mun.ca/pub/pdksh/.

       BTW, the most frequently reported bug is
               echo hi | read a; echo $a   # Does not print hi
       I'm aware of this and there is no need to report it.

VERSION

       This page documents version
                            @(#)PD KSH v5.2.14 99/07/13.2
       of the public domain korn shell.

AUTHORS

       This shell is based on the public domain 7th edition Bourne shell clone
       by Charles Forsyth and parts of the BRL shell by  Doug  A.  Gwyn,  Doug
       Kingston,  Ron  Natalie,  Arnold  Robbins, Lou Salkind and others.  The
       first  release  of  pdksh  was  created  by  Eric  Gisin,  and  it  was
       subsequently  maintained  by John R. MacMillan (chance!john@sq.sq.com),
       and Simon J. Gerraty (sjg@zen.void.oz.au).  The current  maintainer  is
       Michael  Rendell  (michael@cs.mun.ca).   The  CONTRIBUTORS  file in the
       source distribution contains a more complete list of people  and  their
       part in the shell's development.

SEE ALSO

       awk(1),  sh(1),  csh(1), ed(1), getconf(1), getopt(1), sed(1), stty(1),
       vi(1),  dup(2),  execve(2),  getgid(2),  getuid(2),  open(2),  pipe(2),
       wait(2), getopt(3), rand(3), signal(3), system(3), environ(7)

       The KornShell Command and Programming Language, Morris Bolsky and David
       Korn, 1989, ISBN 0-13-516972-0.

       UNIX Shell Programming, Stephen G. Kochan, Patrick H. Wood, Hayden.

       IEEE Standard for information Technology -  Portable  Operating  System
       Interface  (POSIX)  - Part 2: Shell and Utilities, IEEE Inc, 1993, ISBN
       1-55937-255-9.

                                August 19, 1996                       PDKSH(1)