ksh (1)


       ksh - Public domain Korn shell


       ksh [±abCefhikmnprsuvxX] [±o option] [ [ -c command-string [command-
       name] | -s | file ] [argument ...] ]


       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  base-
       name 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:
         ·    the cd command is disabled
         ·    the SHELL, ENV and PATH parameters can't be changed
         ·    command names can't be specified with absolute or relative paths
         ·    the -p option of the command built-in can't be used


       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/pro-
       file 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 men-
       tioned 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 cre-
       ate asynchronous pipelines; && and || are used to  specify  conditional
       execution;  ;;  is used in case statements; (( .. )) are used in arith-
       metic expressions; and lastly, ( .. ) are used to create subshells.

       White-space and meta-characters can be quoted individually using  back-
       slash  (\),  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  men-
       tioned quoting characters (see Quoting below); #, if used at the begin-
       ning of a word, introduces a comment -- everything after the  #  up  to
       the  nearest newline is ignored; $ is used to introduce parameter, com-
       mand and arithmetic substitutions (see Substitution  below);  `  intro-
       duces  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, group-
       ing constructs and function definitions.

       A simple-command consists of some combination of parameter  assignments
       (see  Parameters  below),  input/output  redirections (see Input/Output
       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 sta-
       tus  of a pipeline is that of its last command.  A pipeline may be pre-
       fixed 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  condi-
       tional 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 com-
       plete (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 redi-
       rected, 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 exam-
              { echo foo; echo bar; }
              { echo foo; echo bar<newline>}

       { 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

       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 exe-
              cuted 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 state-
              ment  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  enumer-
              ated  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 state-
              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

       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 defini-
              tion is executed.

       name () command
              Mostly the same as function.  See Functions below.

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

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

       [[ expression ]]
              Similar to the test and [ ... ] commands (described later), with
              the following exceptions:
                ·    Field splitting and file name  generation  are  not  per-
                     formed on arguments.
                ·    The  -a  (and) and -o (or) operators are replaced with &&
                     and ||, respectively.
                ·    Operators (e.g., -f, =, !, etc.) must be unquoted.
                ·    The second operand of != and = expressions  are  patterns
                     (e.g., the comparison in
                                        [[ foobar = f*r ]]
                ·    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, respec-
                ·    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 ]
                                           [[ -n str ]]
                ·    Parameter, command and arithmetic substitutions are  per-
                     formed  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 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 (')

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

       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., sub-
       stitutes 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'
              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 com-
       mand.  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.

       The first step the shell takes in executing a simple-command is to per-
       form substitutions on the words of the command.  There are three  kinds
       of  substitution: parameter, command and arithmetic.  Parameter substi-
       tutions, 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

       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 spec-
       ified command, which is run in a subshell.   For  $(command)  substitu-
       tions,  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 match-
       ing parenthesis, regardless of quoting.  This will hopefully  be  fixed

       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  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  let-
       ters 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 indicies 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  ele-
       ment)  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

       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 exam-
       ple, `FOO=bar' sets  the  parameter  FOO  to  bar;  multiple  parameter
       assignments  can be given on a single command line and they can be fol-
       lowed 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 parame-
       ters as well as the getopts, read and set -A commands.  Lastly, parame-
       ters can be assigned values using assignment  operators  inside  arith-
       metic  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
              if  name  is set and not null, it is substituted, otherwise word
              is substituted.

              if name is set and not  null,  word  is  substituted,  otherwise
              nothing is substituted.

              if  name is set and not null, it is substituted, otherwise it is
              assigned word and the resulting value of name is substituted.

              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  condi-
       tions  only  depend on name being set (as opposed to set and not null).
       If word is needed, parameter, command, arithmetic and  tilde  substitu-
       tion are performed on it; if word is not needed, it is not evaluated.

       The following forms of parameter substitution can also be used:

              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

       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  back-
              ground 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).

       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  sepa-
              rate  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

       @      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  parame-
              ter  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 parame-
              ter 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.

              Set  to  the  number of columns on the terminal or window.  Cur-
              rently 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.

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

              If set, this parameter is assumed to contain the shell  that  is

              The  name  of the file used to store history.  When assigned to,
              history is loaded from the specified file.  Also, several  invo-
              cations  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 his-
              tory file.

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

       HOME   The  default  directory for the cd command and the value substi-
              tuted 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
              Note:  this  parameter is not imported from the environment when
              the shell is started.

              The version of shell and the date the version was created (read-
              only).   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  cur-
              rently 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.

              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).

              A list of files to be checked for mail.  The list is colon sepa-
              rated, and each file may be followed by a ? and a message to  be
              printed  if new mail has arrived.  Command, parameter and arith-
              metic substitution is performed on the message, and, during sub-
              stitution,  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  success-
              fully  changed  directories  since  the shell started, or if the
              shell doesn't know where it is.

              from  a  leading  or  trailing  colon, or two adjacent colons is
              treated as a `.', the current directory.

              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 char-
              acter (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  trac-
              ing  (see  set -x command below).  Parameter, command and arith-
              metic 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  refer-
              enced, it is assigned the next number in a random number series.
              The point in the series can be set by assigning a number to RAN-
              DOM (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.

              The number of seconds since the shell started or, if the parame-
              ter 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 speci-
              fies 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.

   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 OLD-
       PWD parameter is substituted, respectively.   Otherwise,  the  password
       file  is  searched for the login name, and the tilde expression is sub-
       stituted 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
       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  parame-
       ter 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  repre-
              sent itself it must be quoted or appear later in the list.

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

       *(pattern| ... |pattern)

       ?(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 pat-
              terns.   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 [..] expres-
       sion) 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)).

              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 pro-
              cessed 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 com-
              mand 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 associ-
              ated 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 redi-
       rected (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 cre-
       ated 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 assign-
       ment to an integer parameter.

       Expression may contain alpha-numeric parameter identifiers, array  ref-
       erences, 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 nota-
       tion  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 -

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

              ~      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 incre-
                     mented value of the parameter, when  used  as  a  postfix
                     operator, the result is the original value of the parame-

              ++     similar to ++, except the paramter 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.

              <= >= >
                     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

       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:
         ·    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>&-).
         ·    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-processs
              output when the most recently  started  co-process  (instead  of
              when all sharing co-processes) exits.
         ·    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 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
       alias for typeset -fu) may be used to create undefined functions;  when
       an  undefined  function is executed, the shell searches the path speci-
       fied in the FPATH parameter for a file with the same name as the  func-
       tion,  which,  if  found  is read and executed.  If after executing the
       file, the named function is found to be defined, the function  is  exe-
       cuted,  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  exe-

       Since  functions are executed in the current shell environment, parame-
       ter 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  spe-
       cial 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

       Functions  defined  with  the  function  reserved  word   are   treated
       differently  in  the  following ways from functions defined with the ()
         ·    the $0 parameter is set to the name  of  the  function  (Bourne-
              style functions leave $0 untouched).
         ·    parameter  assignments preceeding function calls are not kept in
              the shell environment  (executing  Bourne-style  functions  will
              keep assignments).
         ·    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).  In the future, the following differences
              will also be added:
         ·    A separate trap/signal environment will be used during the  exe-
              cution  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.
         ·    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 deter-
       mined by the state of the posix option (set -o posix) -- if it  is  on,
              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.
         ·    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.
         ·    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.
         ·    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).
         ·    getopts: in posix mode, options must start with  a  -;  in  non-
              posix mode, options can start with either - or +.
         ·    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,  how-
              ever it can be explicitly turned on later.
         ·    set  -: in posix mode, this does not clear the verbose or xtrace
              options; in non-posix mode, it does.
         ·    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 $?' prints 0 in
              posix mode, 1 in non-posix mode.  This construct is used in most
              shell scripts that use the old getopt(1) command.
         ·    argument  expansion of alias, export, readonly, and typeset com-
              mands: in posix mode, normal argument expansion  done;  in  non-
              posix  mode,  field splitting, file globing, brace expansion and
              (normal) tilde expansion are turned off,  and  assignment  tilde
              expansion is turned on.
         ·    signal specification: in posix mode, signals can be specified as
              digits only if signal numbers match POSIX values  (i.e.,  HUP=1,
              INT=2,  QUIT=3,  ABRT=6,  KILL=9, ALRM=14, and TERM=15); in non-
              posix mode, signals can be always digits.
         ·    alias expansion: in posix mode, alias expansion is only  carried
              out  when reading command words; in non-posix mode, alias expan-
              sion is carried out on any word following an alias that ended in
              a space.  For example, the following for loop
              alias a='for ' i='j'
              a i in 1 2; do echo i=$i j=$j; done
       uses parameter i in posix mode, j in non-posix mode.
         ·    test:  in posix mode, the expression "-t" (preceded by some num-
              ber 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
       formed on arguments that look like assignments.  Regular built-in  com-
       mands are different only in that the PATH parameter is not used to find

       The original ksh and POSIX differ somewhat in which commands  are  con-
       sidered 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 with-
              out a value, the existing alias is  listed.   Any  name  with  a
              value defines an alias (see Aliases above).

              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  expan-
              sion, 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  avail-
              able  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  bind-
              ings/macros.   See  Emacs  Editing  Mode  below  for  a complete

       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.  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

              ing 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 new-
              line, 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  recog-

              The  options  are  provided  for  compatibility  with  BSD shell
              scripts: -n suppresses the trailing newline,  -e  enables  back-
              slash interpretation (a no-op, since this is normally done), and
              -E which suppresses backslash interpretation.

       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

              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.

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

       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  num-
              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 argu-
              ments  (or positional parameters, if no arguments are given) and
              to check for legal options.  optstring contains the option  let-
              ters 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  argu-
              ment,  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

              Warning: Changing the value of the shell parameter OPTIND  to  a
              value other than 1, or parsing different sets of arguments with-
              out 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

       jobs [-lpn] [job ...]
              Display information about the specified jobs;  if  no  jobs  are
              specified,  all jobs are displayed.  The -n option causes infor-
              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  speci-
              fied,  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  expres-
              sions  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 new-

       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 logi-
              cal 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  parame-
              ters,  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

       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 com-
              mand 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  parame-
              ter.   Options  can be changed using the ±o option syntax, where
              option is the long name of an option, or using the ±letter  syn-
              tax,  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
               -a         allexport             all new parameters are created
                                                with the export attribute
               -b         notify                Print  job  notification  mes-
                                                sages  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 over-
               -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,
                                                can only be set/unset when the
                                                shell is invoked.
               -k         keyword               Parameter assignments are rec-
                                                ognized 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  inter-

               -p         privileged            Set automatically if, when the
                                                shell starts, the read uid  or
                                                gid  does not match the effec-
                                                tive uid or gid, respectively.
                                                See  Shell Startup above for a
                                                description   of   what   this
               -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
               -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 speci-
                                                fied 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 param-
                                                eter 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 exe-
                                                cuted,  preceded  by the value
                                                of PS4.
               -X         markdirs              Mark directories with a trail-
                                                ing / during file name genera-
                          bgnice                Background jobs are  run  with
                                                lower priority.
                          braceexpand           Enable  brace  expansion (aka,
                                                editing  except that transpose
                                                (^T)  acts  slightly   differ-
                          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

                          physical              Causes the cd and pwd commands
                                                to  use  `physical' (i.e., the
                                                filesystem's)  ..  directories
                                                instead  of `logical' directo-
                                                ries (i.e.,  the shell handles
                                                ..,  which  allows the user to
                                                be obliveous 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
                          posix                 Enable posix mode.  See  POSIX
                                                Mode above.
                          vi                    Enable  vi-like  command  line
                                                editing  (interactive   shells
                          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

              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 oper-
                                    ator (e.g., -r) - it is gen-
                                    erally  better to use a test
                                                  [ X"str" !=  X
                                           instead       (double
                                           quotes  are  used  in
                                           case   str   contains
                                           spaces or file  glob-
                                           ing characters).
               -r file              file exists and is readable.
               -w file              file exists and is writable.
               -x file              file   exists  and  is  exe-
               -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
               -b file              file   is  a  block  special
               -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
               -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
               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.

              precedence over binary operators, may be combined with the  fol-
              lowing 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

              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  argu-
              ment  is  a  binary  operator, then the binary operation is per-
              formed (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 ...]
              (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

              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 com-
              mands;  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 parame-
              ters  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 func-
              tions.  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

               -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

               -Rn               Right  justify  attribute:  n  specifies  the
                                 is used instead of space padding.
               -in               integer  attribute:  n  specifies the base to
                                 use when displaying the integer (if not spec-
                                 ified, the base given in the first assignment
                                 is used).  Parameters with this attribute may
                                 be   assigned  values  containing  arithmetic
               -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 charac-
                                 ters  in  values are converted to lower case.
                                 (In the original Korn shell,  this  parameter
                                 meant  `long  integer'  when used with the -i
               -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 compatabil-
               -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 charac-
                                 ters 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
               -x                Export  attribute:  parameters (or functions)
                                 are placed in the environment of any executed
                                 commands.   Exported functions are not imple-
                                 mented yet.

       ulimit [-acdfHlmnpsStvw] [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
              -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

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

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

              -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 mem-
                     ory used.

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

              -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

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

              -v     Impose a limit of n kbytes on the amount of virtual  mem-
                     ory  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

              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):
              in which the first group of characters is the who part, the sec-
              ond 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 modi-
              fied.  The letters mean:

                      u      the user permissions

                      g      the group permissions

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

                      -      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.

       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 com-
       mands, 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

              is the job-number of the job.

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

              indicates the current state of the job and can be

                     the job has neither stopped or exited (note that  running
                     does  not necessarily mean consuming CPU time -- the pro-
                     cess 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).

              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 col-
       umn 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 charac-
       ters 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  writ-
              ten  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

       The following is a list of editing commands available.   Each  descrip-
       tion  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 bind-
       ings.  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 con-
              sist 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  begin-
              ning  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 com-
              pletion, 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

       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-his-
              tory 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-

       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.
              sor.  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

       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 occurance of the
              next character typed.

       search-character-forward n ^]
              Search forward in the current line for the nth occurance 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  leav-
              ing  search  mode.   Successive search-history commands continue
              searching backward to the next previous occurrence of  the  pat-
              feature, for example.

              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 cur-
              sor 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:

         ·    you start out in insert mode,

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

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

         ·    the  /  and  G  commands move in the opposite direction as the j

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

       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  cur-
       sor  position  as  they are typed, however, some characters are treated
       specially.  In particular, the following characters are taken from cur-
       rent  tty  settings  (see stty(1)) and have their usual meaning (normal
                                 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-tab-

       In  command  mode, each character is interpreted as a command.  Charac-
       ters 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 num-
       ber 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 let-
       ters,  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

       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

              #      insert the comment character (#) at the start of the cur-
                     rent line and return the line to the shell (equivalent to

              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 char-
                     acters: ;, |, &, (, )) and does not contain a  slash  (/)
                     then  command  expansion  is  done,  otherwise  file name
                     expansion is done.  Command expansion will match the big-
                     word  with  the  longest unique match obtained after per-
                     forming command/file name expansion.  <tab> is only  rec-
                     ognized  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 com-
                     pletion 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

       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.

              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.

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

                     same as /, except it searches forward  through  the  his-

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

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

       Edit commands

              na     append text n times: goes into insert mode just after the
                     current position.  The append is only replicated if  com-
                     mand 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  char-
                     acters 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.

                     change  from the current position to the position result-
                     ing from n move-cmds (i.e., delete the  indicated  region
                     and  go  into  insert  mode);  if move-cmd is c, the line

              D      delete to the end of the line.

                     delete from the current position to the position  result-
                     ing 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 charac-
                     ters  instead  of  inserting  before existing characters.
                     The replacement is repeated n times.

              n~     change the case of the next n characters.

                     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 cur-
                     rent position, n times.

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

       Miscellaneous vi commands

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

              ^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 cur-
                     rent line to be deleted and a new prompt to be printed.




       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
       I'm aware of this and there is no need to report it.


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


       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  subse-
       quently  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.


       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(5)

       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

                                August 19, 1996                         ksh(1)