./_Man_SunOS_4.1.3_html/html1/csh

Manual page for CSH_BUILTINS(1)

csh, %, @, alias, bg, break, breaksw, case, continue, default, dirs, else, end, endif, endsw, eval, exec, exit, fg, foreach, glob, goto, hashstat, history, if, jobs, label, limit, logout, notify, onintr, popd, pushd, rehash, repeat, set, setenv, shift, source, stop, suspend, switch, then, umask, unalias, unhash, unlimit, unset, unsetenv, while - C shell built-in commands, see .Hr -url ../html1/csh.1.html csh(1)

C-SHELL BUILTIN COMMANDS

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.

:: Null command. This command is interpreted, but performs no action.
alias [ name [ def ] ]: Assign def to the alias name. def is a list of words that may contain escaped history-substitution metasyntax. name is not allowed to be alias or unalias. If def is omitted, the alias name is displayed along with its current definition. If both name and def are omitted, all aliases are displayed.
bg [%job] ...: Run the current or specified jobs in the background.
break: Resume execution after the end of the nearest enclosing foreach or while loop. The remaining commands on the current line are executed. This allows multilevel breaks to be written as a list of break commands, all on one line.
breaksw: Break from a switch, resuming after the endsw.
case label:: A label in a switch statement.
cd [ dir ]
chdir [ dir ]: Change the shell's working directory to directory dir. If no argument is given, change to the home directory of the user. If dir is a relative pathname not found in the current directory, check for it in those directories listed in the cdpath variable. If dir is the name of a shell variable whose value starts with a /, change to the directory named by that value.
continue: Continue execution of the nearest enclosing while or foreach.
default:: Labels the default case in a switch statement. The default should come after all case labels. Any remaining commands on the command line are first executed.
dirs [ -l ]: Print the directory stack, most recent to the left; the first directory shown is the current directory. With the -l argument, produce an unabbreviated printout; use of the ~ notation is suppressed.
echo [ -n ] list: The words in list are written to the shell's standard output, separated by SPACE characters. The output is terminated with a NEWLINE unless the -n option is used.
eval argument ...: Reads the arguments as input to the shell, and executes the resulting command(s). This is usually used to execute commands generated as the result of command or variable substitution, since parsing occurs before these substitutions. See tset.1 for an example of how to use eval.
exec command: Execute command in place of the current shell, which terminates.
exit [ (expr) ]: The shell exits, either with the value of the status variable, or with the value of the specified by the expression expr.
fg % [ job ]: Bring the current or specified job into the foreground.
foreach var (wordlist)
...
end: The variable var is successively set to each member of wordlist. The sequence of commands between this command and the matching end is executed for each new value of var. (Both foreach and end must appear alone on separate lines.)
: The built-in command continue may be used to continue the loop prematurely and the built-in command break to terminate it prematurely. When this command is read from the terminal, the loop is read up once prompting with ? before any statements in the loop are executed.
glob wordlist: Perform filename expansion on wordlist. Like echo, but no \ escapes are recognized. Words are delimited by null characters in the output.
goto label: The specified label is filename and command expanded to yield a label. The shell rewinds its input as much as possible and searches for a line of the form label: possibly preceded by SPACE or TAB characters. Execution continues after the indicated line. It is an error to jump to a label that occurs between a while or for built-in, and its corresponding end.
hashstat: Print a statistics line indicating how effective the internal hash table has been at locating commands (and avoiding execs). An exec is attempted for each component of the path where the hash function indicates a possible hit, and in each component that does not begin with a `/'.
history [ -hr ] [ n ]: Display the history list; if n is given, display only the n most recent events.

-r: Reverse the order of printout to be most recent first rather than oldest first.
-h: Display the history list without leading numbers. This is used to produce files suitable for sourcing using the -h option to source.

if (expr) command: If the specified expression evaluates to true, the single command with arguments is executed. Variable substitution on command happens early, at the same time it does for the rest of the if command. command must be a simple command, not a pipeline, a command list, or a parenthesized command list. Note: I/O redirection occurs even if expr is false, when command is not executed (this is a bug).
if (expr) then
...
else if (expr2) then
...
else
...
endif: If expr is true, commands up to the first else are executed. Otherwise, if expr2 is true, the commands between the else if and the second else are executed. Otherwise, commands between the else and the endif are executed. Any number of else if pairs are allowed, but only one else. Only one endif is needed, but it is required. The words else and endif must be the first nonwhite characters on a line. The if must appear alone on its input line or after an else.)
jobs[ -l ]: List the active jobs under job control.

-l: List process IDs, in addition to the normal information.

kill [ -sig ] [ pid ] [ %job ] ...
kill -l: Send the TERM (terminate) signal, by default, or the signal specified, to the specified process ID, the job indicated, or the current job. Signals are either given by number or by name. There is no default. Typing kill does not send a signal to the current job. If the signal being sent is TERM (terminate) or HUP (hangup), then the job or process is sent a CONT (continue) signal as well.

-l: List the signal names that can be sent.

limit [ -h ] [ resource [ max-use ] ]: Limit the consumption by the current process or any process it spawns, each not to exceed max-use on the specified resource. If max-use is omitted, print the current limit; if resource is omitted, display all limits.

-h: Use hard limits instead of the current limits. Hard limits impose a ceiling on the values of the current limits. Only the super-user may raise the hard limits.

resource is one of:

cputime: Maximum CPU seconds per process.
filesize: Largest single file allowed.
datasize: Maximum data size (including stack) for the process.
stacksize: Maximum stack size for the process.
coredumpsize: Maximum size of a core dump (file).
descriptors: Maximum value for a file descriptor.

max-use is a number, with an optional scaling factor, as follows:

nh: Hours (for cputime).
nk: n kilobytes. This is the default for all but cputime.
nm: n megabytes or minutes (for cputime).
mm:ss: Minutes and seconds (for cputime).

login [ username|-p ]: Terminate a login shell and invoke login.1 The .logout file is not processed. If username is omitted, login prompts for the name of a user.

-p: Preserve the current environment (variables).

logout: Terminate a login shell.
nice [ +n|-n ] [ command ]: Increment the process priority value for the shell or for command by n. The higher the priority value, the lower the priority of a process, and the slower it runs. When given, command is always run in a subshell, and the restrictions placed on commands in simple if commands apply. If command is omitted, nice increments the value for the current shell. If no increment is specified, nice sets the nice value to 4. The range of nice values is from -20 through 19. Values of n outside this range set the value to the lower, or to the higher boundary, respectively.

+n: Increment the process priority value by n.
-n: Decrement by n. This argument can be used only by the super-user.

nohup [ command ]: Run command with HUPs ignored. With no arguments, ignore HUPs throughout the remainder of a script. When given, command is always run in a subshell, and the restrictions placed on commands in simple if commands apply. All processes detached with & are effectively nohup'd.
notify [ %job ] ...: Notify the user asynchronously when the status of the current, or of specified jobs, changes.
onintr [ - | label]: Control the action of the shell on interrupts. With no arguments, onintr restores the default action of the shell on interrupts. (The shell terminates shell scripts and returns to the terminal command input level). With the - argument, the shell ignores all interrupts. With a label argument, the shell executes a goto label when an interrupt is received or a child process terminates because it was interrupted.
popd [+n]: Pop the directory stack, and cds to the new top directory. The elements of the directory stack are numbered from 0 starting at the top.

+n: Discard the n'th entry in the stack.

pushd [+n | dir]: Push a directory onto the directory stack. With no arguments, exchange the top two elements.

+n: Rotate the n'th entry to the top of the stack and cd to it.
dir: Push the current working directory onto the stack and change to dir.

rehash: Recompute the internal hash table of the contents of directories listed in the path variable to account for new commands added.
repeat count command: Repeat command count times command is subject to the same restrictions as with the one-line if statement.
set [var [ = value ] ]
set var[n] = word: With no arguments, set displays the values of all shell variables. Multiword values are displayed as a parenthesized list. With the var argument alone, set assigns an empty (null) value to the variable var. With arguments of the form var = value set assigns value to var, where value is one of:

word: A single word (or quoted string).
(wordlist): A space-separated list of words enclosed in parentheses.

Values are command and filename expanded before being assigned. The form set var[n] = word replaces the n'th word in a multiword value with word.

setenv [ VAR [ word ] ]: With no arguments, setenv displays all environment variables. With the VAR argument sets the environment variable VAR to have an empty (null) value. (By convention, environment variables are normally given upper-case names.) With both VAR and word arguments setenv sets the environment variable NAME to the value word, which must be either a single word or a quoted string. The most commonly used environment variables, USER, TERM, and PATH, are automatically imported to and exported from the csh variables user, term, and path; there is no need to use setenv for these. In addition, the shell sets the PWD environment variable from the csh variable cwd whenever the latter changes.
shift [ variable ]: The components of argv, or variable, if supplied, are shifted to the left, discarding the first component. It is an error for the variable not to be set, or to have a null value.
source [ -h ] name: Reads commands from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descriptors. An error in a sourced file at any level terminates all nested source commands.

-h: Place commands from the file name on the history list without executing them.

stop [%job] ...: Stop the current or specified background job.
suspend: Stop the shell in its tracks, much as if it had been sent a stop signal with ^Z. This is most often used to stop shells started by su.
switch (string)
case label:
...
breaksw
...
default:
...
breaksw
endsw: Each label is successively matched, against the specified string, which is first command and filename expanded. The file metacharacters *, ? and [...] may be used in the case labels, which are variable expanded. If none of the labels match before a ``default'' label is found, execution begins after the default label. Each case statement and the default statement must appear at the beginning of a line. The command breaksw continues execution after the endsw. Otherwise control falls through subsequent case and default statements as with C. If no label matches and there is no default, execution continues after the endsw.
time [ command ]: With no argument, print a summary of time used by this C shell and its children. With an optional command, execute command and print a summary of the time it uses.
umask [ value ]: Display the file creation mask. With value set the file creation mask. value is given in octal, and is XORed with the permissions of 666 for files and 777 for directories to arrive at the permissions for new files. Common values include 002, giving complete access to the group, and read (and directory search) access to others, or 022, giving read (and directory search) but not write permission to the group and others.
unalias pattern: Discard aliases that match (filename substitution) pattern. All aliases are removed by unalias *.
unhash: Disable the internal hash table.
unlimit [ -h ] [ resource ]: Remove a limitation on resource. If no resource is specified, then all resource limitations are removed. See the description of the limit command for the list of resource names.

-h: Remove corresponding hard limits. Only the super-user may do this.

unset pattern: Remove variables whose names match (filename substitution) pattern. All variables are removed by `unset *'; this has noticeably distasteful side-effects.
unsetenv variable: Remove variable from the environment. Pattern matching, as with unset is not performed.
wait: Wait for background jobs to finish (or for an interrupt) before prompting.
while (expr)
...
end: While expr is true (evaluates to non-zero), repeat commands between the while and the matching end statement. break and continue may be used to terminate or continue the loop prematurely. The while and end must appear alone on their input lines. If the shell's input is a terminal, it prompts for commands with a question-mark until the end command is entered and then performs the commands in the loop.
%[ job ] [ & ]: Bring the current or indicated job to the foreground. With the ampersand, continue running job in the background.
@ [ var =expr ]
@ [ var[n] =expr ]: With no arguments, display the values for all shell variables. With arguments, the variable var, or the n'th word in the value of var, to the value that expr evaluates to. (If [n] is supplied, both var and its n'th component must already exist.)
: If the expression contains the characters >, <, & or |, then at least this part of expr must be placed within parentheses.
: The operators *=, +=, etc., are available as in C. The space separating the name from the assignment operator is optional. Spaces are, however, mandatory in separating components of expr that would otherwise be single words.
: Special postfix operators, ++ and -- increment or decrement name, respectively.

C-SHELL BUILTIN COMMANDS

SEE ALSO