{
    "mode": "man",
    "parameter": "SYSCTL",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/SYSCTL/8/json",
    "generated": "2026-06-15T16:27:59Z",
    "synopsis": "sysctl [options] [variable[=value]] [...]\nsysctl -p [file or regexp] [...]",
    "sections": {
        "NAME": {
            "content": "sysctl - configure kernel parameters at runtime\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "sysctl [options] [variable[=value]] [...]\nsysctl -p [file or regexp] [...]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "sysctl  is  used  to modify kernel parameters at runtime.  The parameters available are those\nlisted under /proc/sys/.  Procfs is required for sysctl support in Linux.  You can use sysctl\nto both read and write sysctl data.\n",
            "subsections": []
        },
        "PARAMETERS": {
            "content": "variable\nThe  name  of  a key to read from.  An example is kernel.ostype.  The '/' separator is\nalso accepted in place of a '.'.\n\nvariable=value\nTo set a key, use the form variable=value where variable is the key and value  is  the\nvalue  to  set  it to.  If the value contains quotes or characters which are parsed by\nthe shell, you may need to enclose the value in double quotes.\n",
            "subsections": [
                {
                    "name": "-n --values",
                    "content": "Use this option to disable printing of the key name when printing values.\n",
                    "flag": "-n",
                    "long": "--values"
                },
                {
                    "name": "-e --ignore",
                    "content": "Use this option to ignore errors about unknown keys.\n",
                    "flag": "-e",
                    "long": "--ignore"
                },
                {
                    "name": "-N --names",
                    "content": "Use this option to only print the names.  It may be useful with shells that have  pro‐\ngrammable completion.\n",
                    "flag": "-N",
                    "long": "--names"
                },
                {
                    "name": "-q --quiet",
                    "content": "Use this option to not display the values set to stdout.\n",
                    "flag": "-q",
                    "long": "--quiet"
                },
                {
                    "name": "-w --write",
                    "content": "Use this option when all arguments prescribe a key to be set.\n",
                    "flag": "-w",
                    "long": "--write"
                },
                {
                    "name": "-p --load",
                    "content": "Load  in  sysctl  settings  from the file specified or /etc/sysctl.conf if none given.\nSpecifying - as filename means reading data from standard input.   Using  this  option\nwill  mean  arguments to sysctl are files, which are read in the order they are speci‐\nfied.  The file argument may be specified as regular expression.\n",
                    "flag": "-p",
                    "long": "--load"
                },
                {
                    "name": "-a --all",
                    "content": "Display all values currently available.\n",
                    "flag": "-a",
                    "long": "--all"
                },
                {
                    "name": "--deprecated",
                    "content": "Include deprecated parameters to --all values listing.\n",
                    "long": "--deprecated"
                },
                {
                    "name": "-b --binary",
                    "content": "Print value without new line.\n",
                    "flag": "-b",
                    "long": "--binary"
                },
                {
                    "name": "--system",
                    "content": "Load settings from all system configuration files. Files are read from directories  in\nthe following list in given order from top to bottom.  Once a file of a given filename\nis loaded, any file of the same name in subsequent directories is ignored.\n/etc/sysctl.d/*.conf\n/run/sysctl.d/*.conf\n/usr/local/lib/sysctl.d/*.conf\n/usr/lib/sysctl.d/*.conf\n/lib/sysctl.d/*.conf\n/etc/sysctl.conf\n",
                    "long": "--system"
                },
                {
                    "name": "-r --pattern",
                    "content": "Only apply settings that match pattern.  The pattern uses extended regular  expression\nsyntax.\n",
                    "flag": "-r",
                    "long": "--pattern"
                },
                {
                    "name": "-A -a",
                    "content": "",
                    "flag": "-a"
                },
                {
                    "name": "-d -h",
                    "content": "",
                    "flag": "-h"
                },
                {
                    "name": "-f -p",
                    "content": "",
                    "flag": "-p"
                },
                {
                    "name": "-X -a",
                    "content": "",
                    "flag": "-a"
                },
                {
                    "name": "-o",
                    "content": "",
                    "flag": "-o"
                },
                {
                    "name": "-x",
                    "content": "",
                    "flag": "-x"
                },
                {
                    "name": "-h --help",
                    "content": "Display help text and exit.\n",
                    "flag": "-h",
                    "long": "--help"
                },
                {
                    "name": "-V --version",
                    "content": "Display version information and exit.\n",
                    "flag": "-V",
                    "long": "--version"
                }
            ]
        },
        "EXAMPLES": {
            "content": "/sbin/sysctl -a\n/sbin/sysctl -n kernel.hostname\n/sbin/sysctl -w kernel.domainname=\"example.com\"\n/sbin/sysctl -p/etc/sysctl.conf\n/sbin/sysctl -a --pattern forward\n/sbin/sysctl -a --pattern forward$\n/sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp'\n/sbin/sysctl --system --pattern '^net.ipv6'\n",
            "subsections": []
        },
        "DEPRECATED PARAMETERS": {
            "content": "The  basereachabletime  and retranstime are deprecated.  The sysctl command does not allow\nchanging values of these parameters.  Users who insist to use  deprecated  kernel  interfaces\nshould push values to /proc file system by other means.  For example:\n\necho 256 > /proc/sys/net/ipv6/neigh/eth0/basereachabletime\n",
            "subsections": []
        },
        "FILES": {
            "content": "/proc/sys\n/etc/sysctl.d/*.conf\n/run/sysctl.d/*.conf\n/usr/local/lib/sysctl.d/*.conf\n/usr/lib/sysctl.d/*.conf\n/lib/sysctl.d/*.conf\n/etc/sysctl.conf\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "sysctl.conf(5) regex(7)\n",
            "subsections": []
        },
        "AUTHOR": {
            "content": "George Staikos ⟨staikos@0wned.org⟩\n",
            "subsections": []
        },
        "REPORTING BUGS": {
            "content": "Please send bug reports to ⟨procps@freelists.org⟩\n\n\n\nprocps-ng                                    2020-02-27                                    SYSCTL(8)",
            "subsections": []
        }
    },
    "summary": "sysctl - configure kernel parameters at runtime",
    "flags": [],
    "examples": [
        "/sbin/sysctl -a",
        "/sbin/sysctl -n kernel.hostname",
        "/sbin/sysctl -w kernel.domainname=\"example.com\"",
        "/sbin/sysctl -p/etc/sysctl.conf",
        "/sbin/sysctl -a --pattern forward",
        "/sbin/sysctl -a --pattern forward$",
        "/sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp'",
        "/sbin/sysctl --system --pattern '^net.ipv6'"
    ],
    "see_also": [
        {
            "name": "sysctl.conf",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/sysctl.conf/5/json"
        },
        {
            "name": "regex",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/regex/7/json"
        }
    ]
}