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LIMITS(1)		  BSD General Commands Manual		     LIMITS(1)

NAME
     limits -- set or display process resource limits

SYNOPSIS
     limits [-C	class |	-P pid | -U user] [-SHB] [-ea]
	    [-bcdfklmnopstuvw [val]]
     limits [-C	class |	-U user] [-SHB]	[-bcdfklmnopstuvw [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 re-
	     source 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.	 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.  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 de-
	     termined, 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 re-
	     source 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 lim-
	       its.  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 lim-
	       its.  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 settings follow
	       this switch, both soft and hard limits are affected until over-
	       ridden later with either	the -S or -H options.

     -e	       Select "eval mode" formatting for output.  This is valid	only
	       in 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.

     -k	[val]  Select or set the kqueues 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 en-
	       tire system is limited to the value displayed by	the
	       kern.maxfiles sysctl(8) variable.

     -o	[val]  Select or set the umtxp resource	limit.	The limit determines
	       the maximal number of the process-shared	locks which may	be si-
	       multaneously created by the processes owned by the user,	see
	       pthread(3).

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

     -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.

     -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 infinite	(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.

     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 su-
     peruser account may raise hard limits, and	when doing so the FreeBSD ker-
     nel will silently lower limits to values less than	specified if the val-
     ues given are too high.

BSD			       January 13, 2018				   BSD

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

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