sysctl(8) - configure kernel parameters at runtime

  • SYSCTL(8)                    System Administration                   SYSCTL(8)
           sysctl - configure kernel parameters at runtime
           sysctl [options] [variable[=value]] [...]
           sysctl -p [file or regexp] [...]
           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.
                  The name of a key to read from.  An  example  is  kernel.ostype.
                  The '/' separator is also accepted in place of a '.'.
                  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  print‐
                  ing 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 all arguments prescribe a key to be set.
           -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
           -a, --all
                  Display all values currently available.
                  Include deprecated parameters to --all values listing.
           -b, --binary
                  Print value without new line.
                  Load  settings  from  all  system configuration files. Files are
                  read 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.
           -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.
           /sbin/sysctl -a
           /sbin/sysctl -n kernel.hostname
           /sbin/sysctl -w kernel.domainname=""
           /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'
           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
           sysctl.conf(5) regex(7)
           George Staikos ⟨[email protected]⟩
           Please send bug reports to ⟨[email protected]⟩
    procps-ng                         2018-02-19                         SYSCTL(8)

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