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), ksh93(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. In ksh93(1), fc, hash, stop,
suspend, times, and type are aliases by default. In ksh93, the follow‐
ing built-ins are bound to the /bin pathname by default and are invoked
if the pathname search encounters an executable command of that name in
the /bin or /usr/bin directory: cat, chown, getconf, head, mkdir,
rmdir, tee, uniq, and wc.
The remaining commands listed in the following table are built into the
shells for reasons such as efficiency or data sharing between command
invocations. They are described on their respective manual pages.
Command Shell
───────────────────────────────────────────────────────────
++**alias csh, ksh, ksh93
bg csh, ksh, ksh93, sh
+*break csh, ksh, ksh93, sh
builtin ksh93
case csh, ksh, ksh93, sh
cat ksh93
cd csh, ksh, ksh93, sh
chdir csh, sh
chown ksh93
command ksh93
+*continue csh, ksh, ksh93, sh
dirs csh
disown ksh93
echo csh, ksh, ksh93, sh
+*eval csh, ksh, ksh93, sh
+*exec csh, ksh, ksh93, sh
+*exit csh, ksh, ksh93, sh
++**export ksh, ksh93, sh
false ksh, ksh93
fc ksh, ksh93
fg csh, ksh, ksh93, sh
for ksh, ksh93, sh
foreach csh
function ksh, ksh93
getconf ksh93
getopts ksh, ksh93, sh
glob csh
goto csh
hash ksh, ksh93, sh
hashstat csh
head ksh93
hist ksh93
history csh
if csh, ksh, ksh93, sh
jobs csh, ksh, ksh93, sh
kill csh, ksh, ksh93, sh
let ksh, ksh93,
limit csh
login csh, ksh, ksh93, sh
logout csh
mkdir ksh93
nice csh
+*newgrp ksh, ksh93, sh
nohup csh
notify csh
onintr csh
popd csh
print ksh, ksh93
printf ksh93
pushd csh
pwd ksh, ksh93, sh
read ksh, ksh93, sh
++**readonly ksh, ksh93, sh
rehash csh
repeat csh
+*return ksh, ksh93, sh
select ksh, ksh93
+set csh, ksh, ksh93, sh
setenv csh
shift csh, ksh, ksh93, sh
sleep ksh93
source csh
stop csh, ksh, ksh93, sh
suspend csh, ksh, sh
switch csh
tee ksh93
test ksh, ksh93, sh
time csh
*times ksh, ksh93, sh
*+trap ksh, ksh93, sh
true ksh, ksh93
type ksh, ksh93, sh
++**typeset ksh, ksh93
ulimit ksh, ksh93, sh
umask csh, ksh, ksh93, sh
+unalias csh, ksh, ksh93
unhash csh
uniq ksh93
unlimit csh
+unset csh, ksh, ksh93, sh
unsetenv csh
until ksh, ksh93, sh
*wait csh, ksh, ksh93, sh
whence ksh, ksh93
while csh, ksh, ksh93, 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 direc‐
tory 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 variable assignment. This means that tilde sub‐
stitution 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 argu‐
ments arg are specified, 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.
Korn Shell, ksh93, 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.
Except for :, true, false, echo, newgrp, and login, all built-in com‐
mands accept -- to indicate end of options. They also interpret the
option --man as a request to display the manual page onto standard
error and -? as a help request which prints a usage message on standard
error.
Commands that are preceded by one or two + 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 assignments.
3. Errors cause a script that contains them to abort.
4. They are not valid function names.
5. 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 sub‐
stitution is performed after the = sign and field splitting
and file name generation are not performed.
In addition to these built-in reserved command words, ksh93 also uses:
: [ arg ... ] The command only expands parameters.
.name [ arg ... ] If name is a function defined with the func‐
tion name reserved word syntax, the function
is executed in the current environment (as
if it had been defined with the name() syn‐
tax.) Otherwise if name refers to a file,
the file is read in its entirety and the
commands are executed in the current shell
environment. The search path specified by
PATH is used to find the directory contain‐
ing the file. If any arguments arg are spec‐
ified, they become the positional parameters
while processing the . command and the orig‐
inal positional parameters are restored upon
completion. Otherwise the positional parame‐
ters are unchanged. The exit status is the
exit status of the last command executed.
SEE ALSOIntro(1), alias(1), break(1), builtin(1), cd(1), chmod(1), csh(1), dis‐
own(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), ksh93(1),
let(1), limit(1), login(1), logout(1), newgrp(1), nice(1), nohup(1),
print(1), printf(1), pwd(1), read(1), readonly(1), set(1), sh(1),
shift(1), sleep(1), suspend(1), test(1)test(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 5.11 20 Nov 2007 shell_builtins(1)
