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shell_builtins(1)                User Commands               shell_builtins(1)



NAME
       shell_builtins,  case,  for,  foreach,  function,  if,  repeat, select,
       switch, until, while - shell command interpreter built-in commands

DESCRIPTION
       The shell command interpreters csh(1), ksh(1), and sh(1)  have  special
       built-in  commands.  The  commands  case,  for,  foreach, function, if,
       repeat, select, switch, until, and while are  commands  in  the  syntax
       recognized by the shells. They are described in the Commands section of
       the manual pages of  the  respective  shells.  The  remaining  commands
       listed in the table below are built into the shells for reasons such as
       efficiency or data  sharing  between  command  invocations.   They  are
       described on their respective manual pages.


       tab(); cw(2.750000i)| cw(2.750000i) lw(2.750000i)| lw(2.750000i).  Com-
       mandShell aliascsh, ksh bgcsh, ksh, sh breakcsh, ksh, sh casecsh,  ksh,
       sh  cdcsh,  ksh,  sh chdircsh, sh continuecsh, ksh, sh dirscsh echocsh,
       ksh, sh evalcsh, ksh, sh execcsh, ksh, sh exitcsh, ksh,  sh  exportksh,
       sh  fcksh  fgcsh, ksh, sh forksh, sh foreachcsh functionksh getoptsksh,
       sh globcsh gotocsh hashksh, sh hashstatcsh historycsh  ifcsh,  ksh,  sh
       jobscsh,  ksh,  sh  killcsh,  ksh, sh letksh limitcsh logincsh, ksh, sh
       logoutcsh, ksh, sh nicecsh newgrpksh, sh nohupcsh  notifycsh  onintrcsh
       popdcsh  printksh  pushdcsh  pwdksh,  sh  readksh,  sh  readonlyksh, sh
       rehashcsh repeatcsh returnksh, sh selectksh setcsh, ksh,  sh  setenvcsh
       shiftcsh,  ksh,  sh  sourcecsh  stopcsh,  ksh,  sh  suspendcsh, ksh, sh
       switchcsh testksh, sh timecsh timesksh,  sh  trapksh,  sh  typeksh,  sh
       typesetksh  ulimitksh,  sh  umaskcsh, ksh, sh unaliascsh, ksh unhashcsh
       unlimitcsh unsetcsh, ksh, sh unsetenvcsh untilksh, sh waitcsh, ksh,  sh
       whenceksh whilecsh, ksh, sh


   Bourne Shell, sh,  Special Commands
       Input/output  redirection  is  now  permitted  for these commands. File
       descriptor 1 is the  default  output  location.  When  Job  Control  is
       enabled,  additional Special Commands are added to the shell's environ-
       ment.

       In addition to these built-in reserved command words, sh also uses:

       :               No effect; the command does nothing. A zero  exit  code
                       is returned.



       .filename       Read and execute commands from filename and return. The
                       search path specified by  PATH  is  used  to  find  the
                       directory containing filename.



   C shell, csh
       Built-in  commands  are executed within the C shell. If a built-in com-
       mand occurs as any component of a pipeline except the last, it is  exe-
       cuted  in  a  subshell.  In addition to these built-in reserved command
       words, csh also uses:

       :               Null command. This command is interpreted, but performs
                       no action.



   Korn Shell, ksh,  Special Commands
       Input/Output  redirection is permitted. Unless otherwise indicated, the
       output is written on file descriptor 1 and the exit status, when  there
       is no syntax error, is zero.

       Commands that are preceded by one or two * (asterisks) are treated spe-
       cially in the following ways:

       1.  Variable assignment lists preceding the command  remain  in  effect
           when the command completes.


       2.  I/O redirections are processed after variable assignments.


       3.  Errors cause a script that contains them to abort.


       4.  Words, following a command preceded by ** that are in the format of
           a variable assignment, are expanded with the same rules as a  vari-
           able  assignment.  This  means that tilde substitution is performed
           after the = sign and word splitting and file  name  generation  are
           not performed.


       In addition to these built-in reserved command words, ksh also uses:

       * : [ arg ... ] The command only expands parameters.



       * .file [ arg ..Read  the  complete file then execute the commands. The
                       commands are executed in the current shell environment.
                       The  search  path specified by PATH is used to find the
                       directory containing file. If  any  arguments  arg  are
                       given,  they  become the positional parameters.  Other-
                       wise, the positional parameters are unchanged. The exit
                       status is the exit status of the last command executed.
                       the loop termination test.



SEE ALSO
       intro(1),  alias(1),  break(1),  cd(1),  chmod(1),   csh(1),   echo(1),
       exec(1),  exit(1), find(1), getoptcvt(1), getopts(1), glob(1), hash(1),
       history(1),  jobs(1),  kill(1),  ksh(1),  let(1),  limit(1),  login(1),
       logout(1),  newgrp(1),  nice(1),  nohup(1),  print(1), pwd(1), read(1),
       readonly(1), set(1), sh(1), shift(1),  suspend(1),  test(1B),  time(1),
       times(1),  trap(1),  typeset(1), umask(1), wait(1), chdir(2), chmod(2),
       creat(2), umask(2), getopt(3C), profile(4), environ(5)




SunOS 5.10                        19 Aug 2003                shell_builtins(1)