shell_builtins, case, for, foreach, function, if, repeat,
select, switch, until, while - shell command interpreter
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 rea-
sons such as efficiency or data sharing between command
invocations. They are described on their respective manual
alias csh, ksh
bg csh, ksh, sh
break csh, ksh, sh
case csh, ksh, sh
cd csh, ksh, sh
chdir csh, sh
continue csh, ksh, sh
echo csh, ksh, sh
eval csh, ksh, sh
exec csh, ksh, sh
exit csh, ksh, sh
export ksh, sh
fg csh, ksh, sh
for ksh, sh
getopts ksh, sh
hash ksh, sh
if csh, ksh, sh
jobs csh, ksh, sh
kill csh, ksh, sh
login csh, ksh, sh
logout csh, ksh, sh
newgrp ksh, sh
pwd ksh, sh
read ksh, sh
readonly ksh, sh
return ksh, sh
set csh, ksh, sh
shift csh, ksh, sh
stop csh, ksh, sh
suspend csh, ksh, sh
switch | csh
test | ksh, sh
time | csh
times | ksh, sh
trap | ksh, sh
type | ksh, sh
typeset | ksh
ulimit | ksh, sh
umask | csh, ksh, sh
unalias | csh, ksh
unhash | csh
unlimit | csh
unset | csh, ksh, sh
unsetenv | csh
until | ksh, sh
wait | csh, ksh, sh
whence | ksh
while | csh, ksh, sh
Bourne Shell, sh, Special Commands
Input/output redirection is now permitted for these com-
mands. File descriptor 1 is the default output location.
When Job Control is enabled, additional Special Commands are
added to the shell's environment.
In addition to these built-in reserved command words, sh
: No effect; the command does nothing. A zero exit code
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 command occurs as any component of a pipeline
except the last, it is executed in a subshell. In addition
to these built-in reserved command words, csh also uses:
: Null command. This command is interpreted, but per-
forms 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 specially 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 assign-
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 variable 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
* : [ arg ... ]
The command only expands parameters.
* .file [ arg ... ]
Read the complete file then execute the commands. The
commands are executed in the current shell environ-
ment. 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.
Otherwise, the positional parameters are unchanged.
The exit status is the exit status of the last command
executed. the loop termination test.
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),
Man(1) output converted with