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371.

Ulimit provides control over the resources available to processes
started by the shell, on systems that allow such control. If an
option is given, it is interpreted as follows:

-S[tab]use the `soft' resource limit
-H[tab]use the `hard' resource limit
-a[tab]all current limits are reported
-c[tab]the maximum size of core files created
-d[tab]the maximum size of a process's data segment
-e[tab]the maximum scheduling priority (`nice')
-f[tab]the maximum size of files written by the shell and its children
-i[tab]the maximum number of pending signals
-l[tab]the maximum size a process may lock into memory
-m[tab]the maximum resident set size
-n[tab]the maximum number of open file descriptors
-p[tab]the pipe buffer size
-q[tab]the maximum number of bytes in POSIX message queues
-r[tab]the maximum real-time scheduling priority
-s[tab]the maximum stack size
-t[tab]the maximum amount of cpu time in seconds
-u[tab]the maximum number of user processes
-v[tab]the size of virtual memory
-x[tab]the maximum number of file locks

If LIMIT is given, it is the new value of the specified resource;
the special LIMIT values `soft', `hard', and `unlimited' stand for
the current soft limit, the current hard limit, and no limit, respectively.
Otherwise, the current value of the specified resource is printed.
If no option is given, then -f is assumed. Values are in 1024-byte
increments, except for -t, which is in seconds, -p, which is in
increments of 512 bytes, and -u, which is an unscaled number of
processes.

372.

The user file-creation mask is set to MODE. If MODE is omitted, or if
`-S' is supplied, the current value of the mask is printed. The `-S'
option makes the output symbolic; otherwise an octal number is output.
If `-p' is supplied, and MODE is omitted, the output is in a form
that may be used as input. If MODE begins with a digit, it is
interpreted as an octal number, otherwise it is a symbolic mode string
like that accepted by chmod(1).

373.

Wait for the specified process and report its termination status. If
N is not given, all currently active child processes are waited for,
and the return code is zero. N may be a process ID or a job
specification; if a job spec is given, all processes in the job's
pipeline are waited for.

374.

Wait for the specified process and report its termination status. If
N is not given, all currently active child processes are waited for,
and the return code is zero. N is a process ID; if it is not given,
all child processes of the shell are waited for.

375.

The `for' loop executes a sequence of commands for each member in a
list of items. If `in WORDS ...;' is not present, then `in "$@"' is
assumed. For each element in WORDS, NAME is set to that element, and
the COMMANDS are executed.

376.

Equivalent to
[tab](( EXP1 ))
[tab]while (( EXP2 )); do
[tab][tab]COMMANDS
[tab][tab](( EXP3 ))
[tab]done
EXP1, EXP2, and EXP3 are arithmetic expressions. If any expression is
omitted, it behaves as if it evaluates to 1.

377.

The WORDS are expanded, generating a list of words. The
set of expanded words is printed on the standard error, each
preceded by a number. If `in WORDS' is not present, `in "$@"'
is assumed. The PS3 prompt is then displayed and a line read
from the standard input. If the line consists of the number
corresponding to one of the displayed words, then NAME is set
to that word. If the line is empty, WORDS and the prompt are
redisplayed. If EOF is read, the command completes. Any other
value read causes NAME to be set to null. The line read is saved
in the variable REPLY. COMMANDS are executed after each selection
until a break command is executed.

378.

Execute PIPELINE and print a summary of the real time, user CPU time,
and system CPU time spent executing PIPELINE when it terminates.
The return status is the return status of PIPELINE. The `-p' option
prints the timing summary in a slightly different format. This uses
the value of the TIMEFORMAT variable as the output format.

379.

Selectively execute COMMANDS based upon WORD matching PATTERN. The
`|' is used to separate multiple patterns.

380.

The `if COMMANDS' list is executed. If its exit status is zero, then the
`then COMMANDS' list is executed. Otherwise, each `elif COMMANDS' list is
executed in turn, and if its exit status is zero, the corresponding
`then COMMANDS' list is executed and the if command completes. Otherwise,
the `else COMMANDS' list is executed, if present. The exit status of the
entire construct is the exit status of the last command executed, or zero
if no condition tested true.