csh.1

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ignored for the remainder of the script.
The second form causes the specified command to be run with hangups
ignored.
All processes detached with `&' are effectively
.I nohup'ed.
.HP 5
.B notify
.NXR "notify command (csh)"
.br
.ns
.HP 5
\fBnotify\ %\fRjob\ ...
.br
Causes the shell to notify the user asynchronously when the status of the
current or specified jobs changes; normally notification is presented
before a prompt.  This is automatic if the shell variable
.I notify
is set.
.HP 5
.B  onintr
.NXR "onintr command (csh)"
.br
.ns
.HP 5
.BR onintr "  \-"
.br
.ns
.HP 5
.BR onintr "  label"
.br
Control the action of the shell on interrupts.
The first form restores the default action of the shell on interrupts
which is to terminate shell scripts or to return to the terminal command
input level.
The second form `onintr \-' causes all interrupts to be ignored.
The final form causes the shell to execute a `goto label' when
an interrupt is received or a child process terminates because
it was interrupted.
.IP
In any case, if the shell is running detached and interrupts are
being ignored, all forms of
.I onintr
have no meaning and interrupts
continue to be ignored by the shell and all invoked commands.
.HP 5
.BR "popd"
.NXR "popd command (csh)"
.br
.ns
.HP 5
.BR "popd" " +n"
.br
Pops the directory stack, returning to the new top directory.
With a argument `+\fIn\fR' discards the \fIn\fR\|th
entry in the stack.
The elements of the directory stack are numbered from 0 starting at the top.
.HP 5
.BR "pushd"
.NXR "pushd command (csh)"
.br
.ns
.HP 5
.BR "pushd" " name"
.br
.ns
.HP 5
.BR "pushd" " +n"
.br
With no arguments,
.B pushd
exchanges the top two elements of the directory stack.
Given a
.I name
argument,
.B pushd
changes to the new directory (using
.PN cd)
and pushes the old current working directory
(as in
.I csw)
onto the directory stack.
With a numeric argument, rotates the \fIn\fR\|th argument of the directory
stack around to be the top element and changes to it.  The members
of the directory stack are numbered from the top starting at 0.
.HP 5
.BR rehash
.NXR "rehash command (csh)"
.br
Causes the internal hash table of the contents of the directories in
the
.I path
variable to be recomputed.  This is needed if new commands are added
to directories in the
.I 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.
.HP 5
.BR repeat " count command"
.NXR "repeat command (csh)"
.br
The specified 
.I command
which is subject to the same restrictions
as the
.I command
in the one line
.I if
statement above,
is executed
.I count
times.
I/O redirections occur exactly once, even if
.I count
is 0.
.HP 5
.B  set
.NXR "set command (csh)"
.br
.ns
.HP 5
.BR set " name"
.br
.ns
.HP 5
.BR set " name=word"
.br
.ns
.HP 5
.BR set " name[index]=word"
.br
.ns
.HP 5
.BR set " name=(wordlist)"
.br
The first form of the command shows the value of all shell variables.
Variables which have other than a single word as value print as a parenthesized
word list.
The second form sets
.I name
to the null string.
The third form sets
.I name
to the single
.I word.
The fourth form sets
the
.I index'th
component of name to word;
this component must already exist.
The final form sets
.I name
to the list of words in
.I wordlist.
In all cases the value is command and file name expanded.
.IP
These arguments may be repeated to set multiple values in a single set command.
Note however, that variable expansion happens for all arguments before any
setting occurs.
.HP 5
.BR setenv " name value"
.NXR "setenv command (csh)"
.br
Sets the value of environment variable
.I name
to be
.I value,
a single string.
The most commonly used environment variable USER, TERM, and PATH
are automatically imported to and exported from the
.PN csh
variables
.I user,
.I term,
and
.I path;
there is no need to use
.I setenv
for these.
.HP 5
.B  shift
.NXR "shift command (csh)"
.br
.ns
.HP 5
.BR shift " variable"
.br
The members of
.I argv
are shifted to the left, discarding
.I argv[1].
It is an error for
.I argv
not to be set or to have less than one word as value.
The second form performs the same function on the specified variable.
.HP 5
.BR source " name"
.NXR "source command (csh)"
.br
.ns
.HP 5
.BR "source \-h" " name"
.br
The shell reads commands from
.I name.
.I Source
commands may be nested; if they are nested too deeply the shell may
run out of file descriptors.
An error in a
.I source
at any level terminates all nested
.I source
commands.
Normally input during 
.I source
commands is not placed on the history list;
the \-h option causes the commands to be placed in the
history list without being executed.
.HP 5
.B stop
.NXR "stop command (csh)"
.br
.ns
.HP 5
\fBstop\ %\fRjob\ ...
.br
Stops the current or specified job which is executing in the background.
.HP 5
.B suspend
.NXR "suspend command (csh)"
.br
.ns
Causes the shell to stop in its tracks, much as if it had been sent a stop
signal with \fB^Z\fR.  This is most often used to stop shells started by
.MS su 1 .
.HP 5
.BR switch " (string)"
.NXR "switch command (csh)"
.br
.ns
.HP 5
.BR case " str1:"
.br
.ns
.HP 5
\    ...
.br
.ns
.HP 5
\   
.B  breaksw
.br
.ns
.HP 5
\&...
.br
.ns
.HP 5
.B  default:
.br
.ns
.HP 5
\    ...
.br
.ns
.HP 5
\   
.B  breaksw
.br
.ns
.HP 5
.B  endsw
.br
Each case label is successively matched, against the specified
.I string
which is first command and file name 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 
.I breaksw
causes execution to continue after the
.I 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
.I endsw.
.HP 5
.B  time
.NXR "time command (csh)"
.br
.ns
.HP 5
.BR time " command"
.br
With no argument, a summary of time used by this shell and its children
is printed.
If arguments are given
the specified simple command is timed and a time summary
as described under the
.I time
variable is printed.  If necessary, an extra shell is created to print the time
statistic when the command completes.
.HP 5
.B umask
.NXR "umask command (csh)"
.br
.ns
.HP 5
.BR umask " value"
.br
The file creation mask is displayed (first form) or set to the specified
value (second form).  The mask is given in octal.  Common values for
the mask are 002 giving all access to the group and read and execute
access to others or 022 giving all access except no write access for
users in the group or others.
.HP 5
.BR unalias " pattern"
.NXR "unalias command (csh)"
.br
All aliases whose names match the specified pattern are discarded.
Thus all aliases are removed by `unalias *'.
It is not an error for nothing to be
.I unaliased.
.HP 5
.BR unhash
.NXR "unhash command (csh)"
.br
Use of the internal hash table to speed location of executed programs
is disabled.
.HP 5
\fBunlimit\fR \fIresource\fR
.br
.ns
.HP 5
\fBunlimit\fR
.NXR "unlimit command (csh)"
.br
Removes the limitation on \fIresource\fR.  If no \fIresource\fR
is specified, then all \fIresource\fR limitations are removed.
.HP 5
.BR unset " pattern"
.NXR "unset command (csh)"
.br
All variables whose names match the specified pattern are removed.
Thus all variables are removed by `unset *'; this has noticeably
distasteful side-effects.
It is not an error for nothing to be
.I unset.
.HP 5
.BR unsetenv " pattern"
.NXR "unsetenv command (csh)"
.br
Removes all variables whose name match the specified pattern from the
environment.  See also the
.I setenv
command above and
.MS printenv 1 .
.HP 5
.B  wait
.NXR "wait command (csh)"
.br
All background jobs are waited for.
It the shell is interactive, then an interrupt can disrupt the wait,
at which time the shell prints names and job numbers of all jobs
known to be outstanding.
.HP 5
.BR while " (expr)"
.NXR "while command (csh)"
.br
.ns
.HP 5
\    ...
.br
.ns
.HP 5
.B  end
.NXR "end command (csh)"
.br
While the specified expression evaluates non-zero, the commands between
the
.I while
and the matching end are evaluated.
.I Break
and
.I continue
may be used to terminate or continue the loop prematurely.
(The
.I while
and
.I end
must appear alone on their input lines.)
Prompting occurs here the first time through the loop as for the
.I foreach
statement if the input is a terminal.
.HP 5
\fB%\fRjob
.br
Brings the specified job into the foreground.
.HP 5
\fB%\fRjob \fB&\fR
.br
Continues the specified job in the background.
.HP 5
.B "@"
.br
.ns
.HP 5
.BR "@" " name = expr"
.br
.ns
.HP 5
.BR "@" " name[index] = expr"
.br
The first form prints the values of all the shell variables.
The second form sets the specified
.I name
to the value of
.I expr.
If the expression contains `<', `>', `&' or `|' then at least
this part of the expression must be placed within `(' `)'.
The third form assigns the value of
.I expr
to the
.I index'th
argument of
.I name.
Both 
.I name
and its
.I index'th
component must already exist.
.IP
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
.I expr
which would otherwise be single words.
.IP
Special postfix `++' and `\-\|\-' operators increment and decrement
.I name
respectively, that is `@  i++'.
.SH Pre-defined And Environment Variables
.NXR "csh command interpreter" "variables"
The following variables have special meaning to the shell.
Of these,
.I argv,
.I cwd,
.I home,
.I path,
.I prompt,
.I shell
and
.I status
are always set by the shell.
Except for
.I cwd
and
.I status
this setting occurs only at initialization;
these variables will not then be modified unless this is done
explicitly by the user.
.PP
This shell copies the environment variable USER into the variable
.I user,