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 param-
              eter 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 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
              /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 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.

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)