SYSCTL(8)                        System Administration                        SYSCTL(8)

NAME
       sysctl - configure kernel parameters at runtime

SYNOPSIS
       sysctl [options] [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 charac‐
              ters which are parsed by the shell, you may need to enclose the value  in
              double quotes.  This requires the -w parameter to use.

       -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
              Use this option when you want to change a sysctl setting.

       -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 spec‐
              ified as regular expression.

       -a, --all
              Display all values currently available.

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

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

       --system
              Load settings from all system configuration files.
              /run/sysctl.d/*.conf
              /etc/sysctl.d/*.conf
              /usr/local/lib/sysctl.d/*.conf
              /usr/lib/sysctl.d/*.conf
              /lib/sysctl.d/*.conf
              /etc/sysctl.conf

       -r, --pattern pattern
              Only apply settings that match pattern.  The pattern uses extended  regu‐
              lar 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.

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 --system --pattern '^net.ipv6'

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

FILES
       /proc/sys
       /etc/sysctl.conf

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

AUTHOR
       George Staikos ⟨staikos@0wned.org⟩

REPORTING BUGS
       Please send bug reports to ⟨procps@freelists.org⟩

procps-ng                               Jan 2012                              SYSCTL(8)

Usage:
 sysctl [options] [variable[=value] ...]

Options:
  -a, --all            display all variables
  -A                   alias of -a
  -X                   alias of -a
      --deprecated     include deprecated parameters to listing
  -b, --binary         print value without new line
  -e, --ignore         ignore unknown variables errors
  -N, --names          print variable names without values
  -n, --values         print only values of a variables
  -p, --load[=<file>]  read values from file
  -f                   alias of -p
      --system         read values from all system directories
  -r, --pattern <expression>
                       select setting that match expression
  -q, --quiet          do not echo variable set
  -w, --write          enable writing a value to variable
  -o                   does nothing
  -x                   does nothing
  -d                   alias of -h

 -h, --help     display this help and exit
 -V, --version  output version information and exit

For more details see sysctl(8).