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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 characters 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  comple‐
              tion.

       -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 specified 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

       -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 sys‐
       tem 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 ⟨[email protected]⟩

REPORTING BUGS
       Please send bug reports to ⟨[email protected]⟩



procps-ng                                              Jan 2012                                             SYSCTL(8)