SYSCTL(8)		    System Manager's Manual		     SYSCTL(8)

NAME
       sysctl - configure kernel parameters at runtime

SYNOPSIS
       sysctl [option ...] variable[=value] ...

       sysctl -p file-or-regexp ...

DESCRIPTION
       sysctl is used to modify kernel parameters at runtime.  The parameters
       available are those listed under /proc/sys/.  Procfs is required for
       sysctl support in Linux.	 You can use sysctl to both read and write
       sysctl data.

PARAMETERS
       variable
	      The name of a key to read from.  An example is kernel.ostype.
	      The '/' separator is also accepted in place of a '.'.

       variable=value
	      To set a key, use the form variable=value where variable is the
	      key and value is the value to set it to.	If the value contains
	      quotes or characters which are parsed by the shell, you may need
	      to enclose the value in double quotes.

       -n, --values
	      Use this option to disable printing of the key name when
	      printing values.

       -e, --ignore
	      Use this option to ignore errors about unknown keys.

       -N, --names
	      Use this option to only print the names.	It may be useful with
	      shells that have programmable completion.

       -q, --quiet
	      Use this option to not display the values set to stdout.

       -w, --write
	      Force all arguments to be write arguments and print an error if
	      they cannot be parsed this way.

       -p[FILE], --load[=FILE]
	      Load in sysctl settings from the file specified or
	      /etc/sysctl.conf if none given.  Specifying - as filename means
	      reading data from standard input. Using this option will mean
	      arguments to sysctl are files, which are read in the order they
	      are specified.  The file argument may be specified as regular
	      expression.

       -a, --all
	      Display all values currently available except deprecated and
	      verboten parameters.

       --deprecated
	      Include deprecated parameters to --all values listing.

       -b, --binary
	      Print value without new line.

       --system
	      Load settings from all system configuration files. See the
	      SYSTEM FILE PRECEDENCE section below.

       -r, --pattern pattern
	      Only apply settings that match pattern.  The pattern uses
	      extended regular expression syntax.

       -A     Alias of -a

       -d     Alias of -h

       -f     Alias of -p

       -X     Alias of -a

       -o     Does nothing, exists for BSD compatibility.

       -x     Does nothing, exists for BSD compatibility.

       -h, --help
	      Display help text and exit.

       -V, --version
	      Display version information and exit.

FILES

       /proc/sys
       /etc/sysctl.d/*.conf
       /run/sysctl.d/*.conf
       /usr/local/lib/sysctl.d/*.conf
       /usr/lib/sysctl.d/*.conf
       /lib/sysctl.d/*.conf
       /etc/sysctl.conf

NOTES
   System file precedence
       When using the --system option, sysctl will read files from directories
       in the following list in given order from top to bottom. Once a file of
       a given filename is loaded, any file of the same name in subsequent
       directories is ignored.

       /etc/sysctl.d/*.conf
       /run/sysctl.d/*.conf
       /usr/local/lib/sysctl.d/*.conf
       /usr/lib/sysctl.d/*.conf
       /lib/sysctl.d/*.conf

       All configuration files are sorted in lexicographic order, regardless
       of the directory they reside in. Configuration files can either be
       completely replaced (by having a new configuration file with the same
       name in a directory of higher priority) or partially replaced (by
       having a configuration file that is ordered later).

       The file /etc/sysctl.conf is read last which means it can
       replace/override any parameters previously set in files in the listed
       directories.


   Deprecated parameters
       The base_reachable_time and retrans_time are deprecated.	 The sysctl
       command does not allow changing values of these parameters.  Users who
       insist to use deprecated kernel interfaces should push values to /proc
       file system by other means.  For example:

       echo 256 > /proc/sys/net/ipv6/neigh/eth0/base_reachable_time


   Verboten parameters
       Certain kernel parameters should not be read due to side-effects and
       will be skipped by sysctl using the --all option.

       stat_refresh
	      This parameter returns no value but flushes per-cpu vm
	      statistics.


EXAMPLES
       /sbin/sysctl -a
       /sbin/sysctl -n kernel.hostname
       /sbin/sysctl -w kernel.domainname="example.com"
       /sbin/sysctl -p/etc/sysctl.conf
       /sbin/sysctl -a --pattern forward
       /sbin/sysctl -a --pattern forward$
       /sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp'
       /sbin/sysctl --pattern '^net.ipv6' --system

SEE ALSO
       proc(5), sysctl.conf(5), regex(7)

REPORTING BUGS
       Please send bug reports to <procps@freelists.org>.

procps-ng			  2024-07-19			     SYSCTL(8)