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 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

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