limits.conf man page on Archlinux

Man page or keyword search:  
man Server   11224 pages
apropos Keyword Search (all sections)
Output format
Archlinux logo
[printable version]

LIMITS.CONF(5)		       Linux-PAM Manual			LIMITS.CONF(5)

       limits.conf - configuration file for the pam_limits module

       The module applies ulimit limits, nice priority and
       number of simultaneous login sessions limit to user login sessions.
       This description of the configuration file syntax applies to the
       /etc/security/limits.conf file and *.conf files in the
       /etc/security/limits.d directory.

       The syntax of the lines is as follows:


       The fields listed above should be filled as follows:


	   ·   a username

	   ·   a groupname, with @group syntax. This should not be confused
	       with netgroups.

	   ·   the wildcard *, for default entry.

	   ·   the wildcard %, for maxlogins limit only, can also be used with
	       %group syntax. If the % wildcard is used alone it is identical
	       to using * with maxsyslogins limit. With a group specified
	       after % it limits the total number of logins of all users that
	       are member of the group.

	   ·   an uid range specified as <min_uid>:<max_uid>. If min_uid is
	       omitted, the match is exact for the max_uid. If max_uid is
	       omitted, all uids greater than or equal min_uid match.

	   ·   a gid range specified as @<min_gid>:<max_gid>. If min_gid is
	       omitted, the match is exact for the max_gid. If max_gid is
	       omitted, all gids greater than or equal min_gid match. For the
	       exact match all groups including the user's supplementary
	       groups are examined. For the range matches only the user's
	       primary group is examined.

	   ·   a gid specified as %:<gid> applicable to maxlogins limit only.
	       It limits the total number of logins of all users that are
	       member of the group with the specified gid.


	       for enforcing hard resource limits. These limits are set by the
	       superuser and enforced by the Kernel. The user cannot raise his
	       requirement of system resources above such values.

	       for enforcing soft resource limits. These limits are ones that
	       the user can move up or down within the permitted range by any
	       pre-existing hard limits. The values specified with this token
	       can be thought of as default values, for normal system usage.

	       for enforcing both soft and hard resource limits together.

	       Note, if you specify a type of '-' but neglect to supply the
	       item and value fields then the module will never enforce any
	       limits on the specified user/group etc. .


	       limits the core file size (KB)

	       maximum data size (KB)

	       maximum filesize (KB)

	       maximum locked-in-memory address space (KB)

	       maximum number of open files

	       maximum resident set size (KB) (Ignored in Linux 2.4.30 and

	       maximum stack size (KB)

	       maximum CPU time (minutes)

	       maximum number of processes

	       address space limit (KB)

	       maximum number of logins for this user except for this with

	       maximum number of all logins on system

	       the priority to run user process with (negative values boost
	       process priority)

	       maximum locked files (Linux 2.4 and higher)

	       maximum number of pending signals (Linux 2.6 and higher)

	       maximum memory used by POSIX message queues (bytes) (Linux 2.6
	       and higher)

	       maximum nice priority allowed to raise to (Linux 2.6.12 and
	       higher) values: [-20,19]

	       maximum realtime priority allowed for non-privileged processes
	       (Linux 2.6.12 and higher)

       All items support the values -1, unlimited or infinity indicating no
       limit, except for priority and nice.

       If a hard limit or soft limit of a resource is set to a valid value,
       but outside of the supported range of the local system, the system may
       reject the new limit or unexpected behavior may occur. If the control
       value required is used, the module will reject the login if a limit
       could not be set.

       In general, individual limits have priority over group limits, so if
       you impose no limits for admin group, but one of the members in this
       group have a limits line, the user will have its limits set according
       to this line.

       Also, please note that all limit settings are set per login. They are
       not global, nor are they permanent; existing only for the duration of
       the session. One exception is the maxlogin option, this one is system
       wide. But there is a race, concurrent logins at the same time will not
       always be detect as such but only counted as one.

       In the limits configuration file, the '#' character introduces a
       comment - after which the rest of the line is ignored.

       The pam_limits module does report configuration problems found in its
       configuration file and errors via syslog(3).

       These are some example lines which might be specified in

	   *		   soft	   core		   0
	   *		   hard	   nofile	   512
	   @student	   hard	   nproc	   20
	   @faculty	   soft	   nproc	   20
	   @faculty	   hard	   nproc	   50
	   ftp		   hard	   nproc	   0
	   @student	   -	   maxlogins	   4
	   :123		   hard	   cpu		   5000
	   @500:	   soft	   cpu		   10000
	   600:700	   hard	   locks	   10

       pam_limits(8), pam.d(5), pam(8), getrlimit(2)getrlimit(3p)

       pam_limits was initially written by Cristian Gafton <>

Linux-PAM Manual		  09/19/2013			LIMITS.CONF(5)

List of man pages available for Archlinux

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net