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LIMITS(1)		FreeBSD	General	Commands Manual		     LIMITS(1)

NAME
     limits -- set or display process resource limits

SYNOPSIS
     limits [-C	class |	-P pid | -U user] [-SHB] [-ea] [-bcdflmnstuvpw [val]]
     limits [-C	class |	-U user] [-SHB]	[-bcdflmnstuvpw	[val]] [-E]
	    [[name=value ...] command]

DESCRIPTION
     The limits	utility	either prints or sets kernel resource limits, and may
     optionally	set environment	variables like env(1) and run a	program	with
     the selected resources.  Three uses of the	limits utility are possible:

     limits [limitflags] [name=value ...] command
	     This usage	sets limits according to limitflags, optionally	sets
	     environment variables given as name=value pairs, and then runs
	     the specified command.

     limits [limitflags]
	     This usage	determines values of resource settings according to
	     limitflags, does not attempt to set them and outputs these	values
	     to	standard output.  By default, this will	output the current
	     kernel resource settings active for the calling process.  Using
	     the -C class or -U	user options, you may also display the current
	     resource settings modified	by the appropriate login class
	     resource limit entries from the login.conf(5) login capabilities
	     database.

     limits -e [limitflags]
	     This usage	determines values of resource settings according to
	     limitflags, but does not set them itself.	Like the previous
	     usage, it outputs these values to standard	output,	except that it
	     will emit them in eval format, suitable for the calling shell.
	     The calling shell is determined by	examining the entries in the
	     /proc file	system for the parent process.	If the shell is	known
	     (i.e., it is one of sh, csh, bash,	tcsh, ksh, pdksh or rc),
	     limits emits limit	or ulimit commands in the format understood by
	     that shell.  If the name of the shell cannot be determined, then
	     the ulimit	format used by sh(1) is	used.

	     This is very useful for setting limits used by scripts, or	prior
	     launching of daemons and other background tasks with specific
	     resource limit settings, and provides the benefit of allowing
	     global configuration of maximum resource usage by maintaining a
	     central database of settings in the login class database.

	     Within a shell script, limits will	normally be used with eval
	     within backticks as follows:

		   eval	`limits	-e -C daemon`

	     which causes the output of	limits to be evaluated and set by the
	     current shell.

     The value of limitflags specified in the above contains one or more of
     the following options:

     -C	class  Use current resource values, modified by	the resource entries
	       applicable for the login	class class.

     -U	user   Use current resource values, modified by	the resource entries
	       applicable to the login class the user belongs to.  If user
	       does not	belong to any class, then the resource capabilities
	       for the ``default'' class are used, if it exists, or the
	       ``root''	class if the user is a superuser account.

     -P	pid    Select or set limits for	the process identified by the pid.

     -S	       Select display or setting of ``soft'' (or current) resource
	       limits.	If specific limits settings follow this	switch,	only
	       soft limits are affected	unless overridden later	with either
	       the -H or -B options.

     -H	       Select display or setting of ``hard'' (or maximum) resource
	       limits.	If specific limits settings follow this	switch,	only
	       hard limits are affected	until overridden later with either the
	       -S or -B	options.

     -B	       Select display or setting of both ``soft'' (current) or
	       ``hard''	(maximum) resource limits.  If specific	limits set-
	       tings follow this switch, both soft and hard limits are
	       affected	until overridden later with either the -S or -H
	       options.

     -e	       Select ``eval mode'' formatting for output.  This is valid only
	       on display mode and cannot be used when running a command.  The
	       exact syntax used for output depends upon the type of shell
	       from which limits is invoked.

     -b	[val]  Select or set the sbsize	resource limit.

     -c	[val]  Select or set (if val is	specified) the coredumpsize resource
	       limit.  A value of 0 disables core dumps.

     -d	[val]  Select or set (if val is	specified) the datasize	resource
	       limit.

     -f	[val]  Select or set the filesize resource limit.

     -l	[val]  Select or set the memorylocked resource limit.

     -m	[val]  Select or set the memoryuse size	limit.

     -n	[val]  Select or set the openfiles resource limit.  The	system-wide
	       limit on	the maximum number of open files per process can be
	       viewed by examining the kern.maxfilesperproc sysctl(8) vari-
	       able.  The total	number of simultaneously open files in the
	       entire system is	limited	to the value displayed by the
	       kern.maxfiles sysctl(8) variable.

     -s	[val]  Select or set the stacksize resource limit.

     -t	[val]  Select or set the cputime resource limit.

     -u	[val]  Select or set the maxproc resource limit.  The system-wide
	       limit on	the maximum number of processes	allowed	per UID	can be
	       viewed by examining the kern.maxprocperuid sysctl(8) variable.
	       The maximum number of processes that can	be running simultane-
	       ously in	the entire system is limited to	the value of the
	       kern.maxproc sysctl(8) variable.

     -v	[val]  Select or set the virtualmem resource limit.  This limit	encom-
	       passes the entire VM space for the user process and is inclu-
	       sive of text, data, bss,	stack, brk(2), sbrk(2) and mmap(2)'d
	       space.

     -p	[val]  Select or set the pseudoterminals resource limit.

     -w	[val]  Select or set the swapuse resource limit.

     Valid values for val in the above set of options consist of either	the
     string ``infinity'', ``inf'', ``unlimited'' or ``unlimit''	for an infi-
     nite (or kernel-defined maximum) limit, or	a numeric value	optionally
     followed by a suffix.  Values which relate	to size	default	to a value in
     bytes, or one of the following suffixes may be used as a multiplier:

	   b	 512 byte blocks.
	   k	 kilobytes (1024 bytes).
	   m	 megabytes (1024*1024 bytes).
	   g	 gigabytes.
	   t	 terabytes.

     The cputime resource defaults to a	number of seconds, but a multiplier
     may be used, and as with size values, multiple values separated by	a
     valid suffix are added together:

	   s	 seconds.
	   m	 minutes.
	   h	 hours.
	   d	 days.
	   w	 weeks.
	   y	 365 day years.

     -E	       Cause limits to completely ignore the environment it inherits.

     -a	       Force all resource settings to be displayed even	if other spe-
	       cific resource settings have been specified.  For example, if
	       you wish	to disable core	dumps when starting up the Usenet News
	       system, but wish	to set all other resource settings as well
	       that apply to the ``news'' account, you might use:

		     eval `limits -U news -aBec	0`

	       As with the setrlimit(2)	call, only the superuser may raise
	       process ``hard''	resource limits.  Non-root users may, however,
	       lower them or change ``soft'' resource limits within to any
	       value below the hard limit.  When invoked to execute a program,
	       the failure of limits to	raise a	hard limit is considered a
	       fatal error.

EXIT STATUS
     The limits	utility	exits with EXIT_FAILURE	if usage is incorrect in any
     way; i.e.,	an invalid option, or set/display options are selected in the
     same invocation, -e is used when running a	program, etc.  When run	in
     display or	eval mode, limits exits	with a status of EXIT_SUCCESS.	When
     run in command mode and execution of the command succeeds,	the exit sta-
     tus will be whatever the executed program returns.

SEE ALSO
     csh(1), env(1), limit(1), sh(1), getrlimit(2), setrlimit(2),
     login_cap(3), login.conf(5), rctl(8), sysctl(8)

BUGS
     The limits	utility	does not handle	commands with equal (`=') signs	in
     their names, for obvious reasons.

     When eval output is selected, the /proc file system must be installed and
     mounted for the shell to be correctly determined, and therefore output
     syntax correct for	the running shell.  The	default	output is valid	for
     sh(1), so this means that any usage of limits in eval mode	prior mounting
     /proc may only occur in standard bourne shell scripts.

     The limits	utility	makes no effort	to ensure that resource	settings emit-
     ted or displayed are valid	and settable by	the current user.  Only	a
     superuser account may raise hard limits, and when doing so	the FreeBSD
     kernel will silently lower	limits to values less than specified if	the
     values given are too high.

FreeBSD	9.3		       January 23, 2012			   FreeBSD 9.3

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | SEE ALSO | BUGS

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