Builtin commands

%job

A synonym for the fg builtin command.

%job &

A synonym for the bg builtin command.

:

Does nothing, successfully.

@
@ name = expr

@ name[index] = expr

The first form prints the values of all shell variables. The second form sets the specified name to the value of expr. If expr contains `<', `>', `&' or `' then at least that part of expr must be placed within `()'. The third form assigns the value of expr to the index'th argument of name. Both name and its index'th component must already exist.

alias [name [wordlist]]

Without arguments, prints all aliases. With name, prints the alias for name. With name and wordlist, assigns wordlist as the alias of name. wordlist is command and filename substituted. name may not be `alias' or `unalias'. See also the unalias builtin command.

alloc

Shows the amount of dynamic memory acquired, broken down into used and free memory. With an argument shows the number of free and used blocks in each size category. The categories start at size 8 and double at each step. This command's output may vary across system types, since systems other than the VAX may use a different memory allocator.

bg [%job ...]

Puts the specified jobs (or, without arguments, the current job) into the background, continuing each if it is stopped. job may be a number, a string, `', `%', `+' or `-' as described under Jobs.

bindkey [-l|-d|-e|-v|-u] (+)
bindkey [-a] [-b] [-k] [-r] [--] key (+)

bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)

Without options, the first form lists all bound keys and the editor command to which each is bound, the second form lists the editor command to which key is bound and the third form binds the editor command command to key. Options include:

break

Causes execution to resume after the end of the nearest enclosing foreach or while. The remaining commands on the current line are executed. Multi-level breaks are thus possible by writing them all on one line.

breaksw

Causes a break from a switch, resuming after the endsw.

builtins (+)

Prints the names of all builtin commands.

bye (+)

A synonym for the logout builtin command. Available only if the shell was so compiled; see the version shell variable.

case label:

A label in a switch statement as discussed below.

cd [-p] [-l] [-n|-v] [name]

If a directory name is given, changes the shell's working directory to name. If not, changes to home. If name is `-' it is interpreted as the previous working directory (see Other substitutions). (+) If name is not a subdirectory of the current directory (and does not begin with `/', `./' or `../'), each component of the variable cdpath is checked to see if it has a subdirectory name. Finally, if all else fails but name is a shell variable whose value begins with `/', then this is tried to see if it is a directory.

chdir

A synonym for the cd builtin command.

complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)

Without arguments, lists all completions. With command, lists completions for command. With command and word etc., defines completions.

continue

Continues execution of the nearest enclosing while or foreach. The rest of the commands on the current line are executed.

default:

Labels the default case in a switch statement. It should come after all case labels.

dirs [-l] [-n|-v]
dirs -S|-L [filename] (+)

dirs -c (+)

The first form prints the directory stack. The top of the stack is at the left and the first directory in the stack is the current directory. With -l, `~' or `~name\fP' in the output is expanded explicitly to home or the pathname of the home directory for user name\fP. (+) With -n, entries are wrapped before they reach the edge of the screen. (+) With -v, entries are printed one per line, preceded by their stack postions. (+) If more than one of -n or -v is given, -v takes precedence. -p is accepted but does nothing.

echo [-n] word ...

Writes each word to the shell's standard output, separated by spaces and terminated with a newline. The echo_style shell variable may be set to emulate (or not) the flags and escape sequences of the BSD and/or System V versions of echo; see echo(1).

echotc [-sv] arg ... (+)

Exercises the terminal capabilities (see termcap(5)) in args. For example, 'echotc home' sends the cursor to the home position, 'echotc cm 3 10' sends it to column 3 and row 10, and 'echotc ts 0; echo "This is a test."; echotc fs' prints "This is a test." in the status line.

endsw

See the description of the foreach, if, switch, and while statements below.

eval arg ...

Treats the arguments as input to the shell and executes the resulting command(s) in the context of the current shell. 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 a sample use of eval.

exec command

Executes the specified command in place of the current shell.

exit [expr]

The shell exits either with the value of the specified expr (an expression, as described under Expressions) or, without expr, with the value of the status variable.

fg [%job ...]

Brings the specified jobs (or, without arguments, the current job) into the foreground, continuing each if it is stopped. job may be a number, a string, `', `%', `+' or `-' as described under Jobs. See also the run-fg-editor editor command.

filetest -op file ... (+)

Applies op (which is a file inquiry operator as described under File inquiry operators) to each file and returns the results as a space-separated list.

foreach name (wordlist)
...

end

Successively sets the variable name to each member of wordlist and executes the sequence of commands between this command and the matching end. (Both foreach and end must appear alone on separate lines.) The builtin command continue may be used to continue the loop prematurely and the builtin command break to terminate it prematurely. When this command is read from the terminal, the loop is read once prompting with `foreach? ' (or prompt2) before any statements in the loop are executed. If you make a mistake typing in a loop at the terminal you can rub it out.

getspath (+)

Prints the system execution path. (TCF only)

getxvers (+)

Prints the experimental version prefix. (TCF only)

glob wordlist

Like echo, but no `\' escapes are recognized and words are delimited by null characters in the output. Useful for programs which wish to use the shell to filename expand a list of words.

goto word

word is filename and command-substituted to yield a string of the form `label'. The shell rewinds its input as much as possible, searches for a line of the form `label:', possibly preceded by blanks or tabs, and continues execution after that line.

hashstat

Prints a statistics line indicating how effective the internal hash table has been at locating commands (and avoiding exec's). An exec is attempted for each component of the path where the hash function indicates a possible hit, and in each component which does not begin with a `/'.

On machines without vfork(2), prints only the number and size of hash buckets. history [-hr] [n]
history -S|-L|-M [filename] (+)

history -c (+)

The first form prints the history event list. If n is given only the n most recent events are printed or saved. With -h, the history list is printed without leading numbers and with time-stamps in comment form. (This can be used to produce files suitable for loading with 'history -L' or 'source -h'.) With -r, the order of printing is most recent first rather than oldest first.

hup [command] (+)

With command, runs command such that it will exit on a hangup signal and arranges for the shell to send it a hangup signal when the shell exits. Note that commands may set their own response to hangups, overriding hup. Without an argument (allowed only in a shell script), causes the shell to exit on a hangup for the remainder of the script. See also Signal handling and the nohup builtin command.

if (expr) command

If expr (an expression, as described under Expressions) evaluates true, then command 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 an alias, a pipeline, a command list or a parenthesized command list, but it may have arguments. Input/output redirection occurs even if expr is false and command is thus not executed; this is a bug.

if (expr) then
...
else if (expr2) then
...
else
...

endif

If the specified expr is true then the commands to the first else are executed; otherwise if expr2 is true then the commands to the second else are executed, etc. Any number of else-if pairs are possible; only one endif is needed. The else part is likewise optional. (The words else and endif must appear at the beginning of input lines; the if must appear alone on its input line or after an else.)

inlib shared-library ... (+)

Adds each shared-library to the current environment. There is no way to remove a shared library. (Domain/OS only)

jobs [-l]

Lists the active jobs. With -l, lists process IDs in addition to the normal information. On TCF systems, prints the site on which each job is executing.

kill [-signal] %job|pid ...

kill -l

The first form sends the specified signal (or, if none is given, the TERM (terminate) signal) to the specified jobs or processes. job may be a number, a string, `', `%', `+' or `-' as described under Jobs. Signals are either given by number or by name (as given in /usr/include/signal.h, stripped of the prefix `SIG'). There is no default job; saying just `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. The second form lists the signal names.

limit [-h] [resource [maximum-use]]

Limits the consumption by the current process and each process it creates to not individually exceed maximum-use on the specified resource. If no maximum-use is given, then the current limit is printed; if no resource is given, then all limitations are given. If the -h flag is given, the hard limits are used instead of the current limits. The hard limits impose a ceiling on the values of the current limits. Only the super-user may raise the hard limits, but a user may lower or raise the current limits within the legal range.

log (+)

Prints the watch shell variable and reports on each user indicated in watch who is logged in, regardless of when they last logged in. See also watchlog.

login

Terminates a login shell, replacing it with an instance of /bin/login. This is one way to log off, included for compatibility with sh(1).

logout

Terminates a login shell. Especially useful if ignoreeof is set.

ls-F [-switch ...] [file ...] (+)

Lists files like `ls -F', but much faster. It identifies each type of special file in the listing with a special character:

migrate -site (+)

The first form migrates the process or job to the site specified or the default site determined by the system path. The second form is equivalent to `migrate -site $$': it migrates the current process to the specified site. Migrating the shell itself can cause unexpected behavior, since the shell does not like to lose its tty. (TCF only)

newgrp [-] group (+)

Equivalent to `exec newgrp'; see newgrp(1). Available only if the shell was so compiled; see the version shell variable.

nice [+number] [command]

Sets the scheduling priority for the shell to number, or, without number, to 4. With command, runs command at the appropriate priority. The greater the number, the less cpu the process gets. The super-user may specify negative priority by using `nice -number ...'. Command is always executed in a sub-shell, and the restrictions placed on commands in simple if statements apply.

nohup [command]

With command, runs command such that it will ignore hangup signals. Note that commands may set their own response to hangups, overriding nohup. Without an argument (allowed only in a shell script), causes the shell to ignore hangups for the remainder of the script. See also Signal handling and the hup builtin command.

notify [%job ...]

Causes the shell to notify the user asynchronously when the status of any of the specified jobs (or, without %job, the current job) changes, instead of waiting until the next prompt as is usual. job may be a number, a string, `', `%', `+' or `-' as described under Jobs. See also the notify shell variable.

onintr [-|label]

Controls the action of the shell on interrupts. Without arguments, restores the default action of the shell on interrupts, which is to terminate shell scripts or to return to the terminal command input level. With `-', causes all interrupts to be ignored. With label, causes the shell to execute a `goto label' when an interrupt is received or a child process terminates because it was interrupted.

popd [-p] [-l] [-n|-v] [+n]

Without arguments, pops the directory stack and returns to the new top directory. With a number `+n', discards the n'th entry in the stack.

printenv [name] (+)

Prints the names and values of all environment variables or, with name, the value of the environment variable name.

pushd [-p] [-l] [-n|-v] [name|+n]

Without arguments, exchanges the top two elements of the directory stack. If pushdtohome is set, pushd without arguments does `pushd ~', like cd. (+) With name, pushes the current working directory onto the directory stack and changes to name. If name is `-' it is interpreted as the previous working directory (see Filename substitution). (+) If dunique is set, pushd removes any instances of name from the stack before pushing it onto the stack. (+) With a number `+n', rotates the nth element of the directory stack around to be the top element and changes to it. If dextract is set, however, `pushd +n' extracts the nth directory, pushes it onto the top of the stack and changes to it. (+)

rehash

Causes the internal hash table of the contents of the directories in the path variable to be recomputed. This is needed if new commands are added to directories in path while you are logged in. This should only be necessary if you add commands to one of your own directories, or if a systems programmer changes the contents of one of the system directories. Also flushes the cache of home directories built by tilde expansion.

repeat count command

The specified command, which is subject to the same restrictions as the command in the one line if statement above, is executed count times. I/O redirections occur exactly once, even if count is 0.

rootnode //nodename (+)

Changes the rootnode to //nodename, so that `/' will be interpreted as `//nodename'. (Domain/OS only)

sched (+)
sched [+]hh:mm command (+)

sched -n (+)

The first form prints the scheduled-event list. The sched shell variable may be set to define the format in which the scheduled-event list is printed. The second form adds command to the scheduled-event list. For example,

set -r name=(wordlist) ... (+)

The first form of the command prints the value of all shell variables. Variables which contain more than a single word print as a parenthesized word list. The second form sets name to the null string. The third form sets name to the single word. The fourth form sets name to the list of words in wordlist. In all cases the value is command and filename expanded. The fifth form sets the index'th component of name to word; this component must already exist. The sixth form lists the names (only) of all shell variables which are read-only. The seventh form makes name read-only, whether or not it has a value. The second form sets name to the null string. The eighth and ninth forms are the same as the third and fourth forms, but make name read-only at the same time.

setenv [name [value]]

Without arguments, prints the names and values of all environment variables. Given name, sets the environment variable name to value or, without value, to the null string.

setpath path (+)

Equivalent to setpath(1). (Mach only)

setspath LOCAL|site|cpu ... (+)

Sets the system execution path. (TCF only)

settc cap value (+)

Tells the shell to believe that the terminal capability cap (as defined in termcap(5)) has the value value. No sanity checking is done. Concept terminal users may have to `settc xn no' to get proper wrapping at the rightmost column.

setty [-d|-q|-x] [-a] [[+|-]mode] (+)

Controls which tty modes (see Terminal management) the shell does not allow to change. -d, -q or -x tells setty to act on the `edit', `quote' or `execute' set of tty modes respectively; without -d, -q or -x, `execute' is used.

setxvers [string] (+)

Set the experimental version prefix to string, or removes it if string is omitted. (TCF only)

shift [variable]

Without arguments, discards argv[1] and shifts the members of argv to the left. It is an error for argv not to be set or to have less than one word as value. With variable, performs the same function on variable.

source [-h] name [args ...]

The shell reads and executes commands from name. The commands are not placed on the history list. If any args are given, they are placed in argv. (+) source commands may be nested; if they are nested too deeply the shell may run out of file descriptors. An error in a source at any level terminates all nested source commands. With -h, commands are placed on the history list instead of being executed, much like `history -L'.

stop %job|pid ...

Stops the specified jobs or processes which are executing in the background. job may be a number, a string, `', `%', `+' or `-' as described under Jobs. There is no default job; saying just `stop' does not stop the current job.

suspend

Causes the shell to stop 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(1).

switch (string)
case str1:

...

default:

endsw

Each case 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, then the execution begins after the default label. Each case label and the default label must appear at the beginning of a line. The command breaksw causes execution to continue after the endsw. Otherwise control may fall through case labels and default labels as in C. If no label matches and there is no default, execution continues after the endsw.

telltc (+)

Lists the values of all terminal capabilities (see termcap(5)).

time [command]

Executes command (which must be a simple command, not an alias, a pipeline, a command list or a parenthesized command list) and prints a time summary as described under the time variable. If necessary, an extra shell is created to print the time statistic when the command completes. Without command, prints a time summary for the current shell and its children.

umask [value]

Sets the file creation mask to value, which is given in octal. Common values for the mask are 002, giving all access to the group and read and execute access to others, and 022, giving read and execute access to the group and others. Without value, prints the current file creation mask.

unalias pattern

Removes all aliases whose names match pattern. `unalias *' thus removes all aliases. It is not an error for nothing to be unaliased.

uncomplete pattern (+)

Removes all completions whose names match pattern. `uncomplete *' thus removes all completions. It is not an error for nothing to be uncompleted.

unhash

Disables use of the internal hash table to speed location of executed programs.

universe universe (+)

Sets the universe to universe. (Masscomp/RTU only)

unlimit [-h] [resource]

Removes the limitation on resource or, if no resource is specified, all resource limitations. With -h, the corresponding hard limits are removed. Only the super-user may do this.

unset pattern

Removes all variables whose names match pattern, unless they are read-only. `unset *' thus removes all variables unless they are read-only; this is a bad idea. It is not an error for nothing to be unset.

unsetenv pattern

Removes all environment variables whose names match pattern. `unsetenv *' thus removes all environment variables; this is a bad idea. It is not an error for nothing to be unsetenved.

ver [systype [command]] (+)

Without arguments, prints SYSTYPE. With systype, sets SYSTYPE to systype. With systype and command, executes command under systype. systype may be `bsd4.3' or `sys5.3'. (Domain/OS only)

wait

The shell waits for all background jobs. If the shell is interactive, an interrupt will disrupt the wait and cause the shell to print the names and job numbers of all outstanding jobs.

warp universe (+)

Sets the universe to universe. (Convex/OS only)

watchlog (+)

An alternate name for the log builtin command (q.v.). Available only if the shell was so compiled; see the version shell variable.

where command (+)

Reports all known instances of command, including aliases, builtins and executables in path.

which command (+)

Displays the command that will be executed by the shell after substitutions, path searching, etc. The builtin command is just like which(1), but it correctly reports tcsh aliases and builtins and is 10 to 100 times faster. See also the which-command editor command.

while (expr)
...

end

Executes the commands between the while and the matching end while expr (an expression, as described under Expressions) evaluates non-zero. while and end must appear alone on their input lines. break and continue may be used to terminate or continue the loop prematurely. If the input is a terminal, the user is prompted the first time through the loop as with foreach.

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