# SYSTEMD-SYSCTL.SERVICE - Configure kernel parameters at boot - man(8) - [phpMan]

[_SYSTEMD-SYSCTL.SERVICE_(8)](https://www.chedong.com/phpMan.php/man/SYSTEMD-SYSCTL.SERVICE/8/markdown)              systemd-sysctl.service              [_SYSTEMD-SYSCTL.SERVICE_(8)](https://www.chedong.com/phpMan.php/man/SYSTEMD-SYSCTL.SERVICE/8/markdown)

## NAME
       systemd-sysctl.service, systemd-sysctl - Configure kernel parameters at boot

## SYNOPSIS


       **/usr/lib/systemd/systemd-sysctl **[OPTIONS...] [_CONFIGFILE_...]

       systemd-sysctl.service

## DESCRIPTION
       systemd-sysctl.service is an early boot service that configures [**sysctl**(8)](https://www.chedong.com/phpMan.php/man/sysctl/8/markdown) kernel parameters
       by invoking **/usr/lib/systemd/systemd-sysctl**.

       When invoked with no arguments, **/usr/lib/systemd/systemd-sysctl **applies all directives from
       configuration files listed in [**sysctl.d**(5)](https://www.chedong.com/phpMan.php/man/sysctl.d/5/markdown). If one or more filenames are passed on the command
       line, only the directives in these files are applied.

       In addition, **--prefix= **option may be used to limit which sysctl settings are applied.

       See [**sysctl.d**(5)](https://www.chedong.com/phpMan.php/man/sysctl.d/5/markdown) for information about the configuration of sysctl settings. After sysctl
       configuration is changed on disk, it must be written to the files in /proc/sys/ before it
       takes effect. It is possible to update specific settings, or simply to reload all
       configuration, see Examples below.

## OPTIONS
### --prefix=
           Only apply rules with the specified prefix.

           Added in version 230.

### --strict=
           Always return non-zero exit code on failure (including invalid sysctl variable name and
           insufficient permissions), unless the sysctl variable name is prefixed with a "-"
           character.

           Added in version 252.

### --cat-config
           Copy the contents of config files to standard output. Before each file, the filename is
           printed as a comment.

### --tldr
           Copy the contents of config files to standard output. Only the "interesting" parts of the
           configuration files are printed, comments and empty lines are skipped. Before each file,
           the filename is printed as a comment.

### --no-pager
           Do not pipe output into a pager.

### -h --help
           Print a short help text and exit.

### --version
           Print a short version string and exit.

## CREDENTIALS
       **systemd-sysctl **supports the service credentials logic as implemented by
       _ImportCredential=_/_LoadCredential=_/_SetCredential=_ (see [**systemd.exec**(5)](https://www.chedong.com/phpMan.php/man/systemd.exec/5/markdown) for details). The
       following credentials are used when passed in:

       _sysctl.extra_
           The contents of this credential may contain additional lines to operate on. The
           credential contents should follow the same format as any other sysctl.d/ drop-in
           configuration file. If this credential is passed it is processed after all of the drop-in
           files read from the file system. The settings configured in the credential hence take
           precedence over those in the file system.

           Added in version 252.

       Note that by default the systemd-sysctl.service unit file is set up to inherit the
       "sysctl.extra" credential from the service manager.

## EXAMPLES
### Example 1. Reset all sysctl settings

           systemctl restart systemd-sysctl

### Example 2. View coredump handler configuration

           # sysctl kernel.core_pattern
           kernel.core_pattern = |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I

### Example 3. Update coredump handler configuration

           # /usr/lib/systemd/systemd-sysctl --prefix kernel.core_pattern

       This searches all the directories listed in [**sysctl.d**(5)](https://www.chedong.com/phpMan.php/man/sysctl.d/5/markdown) for configuration files and writes
       /proc/sys/kernel/core_pattern.

### Example 4. Update coredump handler configuration according to a specific file

           # /usr/lib/systemd/systemd-sysctl 50-coredump.conf

       This applies all the settings found in 50-coredump.conf. Either
       /etc/sysctl.d/50-coredump.conf, or /run/sysctl.d/50-coredump.conf, or
       /usr/lib/sysctl.d/50-coredump.conf will be used, in the order of preference.

       See [**sysctl**(8)](https://www.chedong.com/phpMan.php/man/sysctl/8/markdown) for various ways to directly apply sysctl settings.

## SEE ALSO
       [**systemd**(1)](https://www.chedong.com/phpMan.php/man/systemd/1/markdown), [**sysctl.d**(5)](https://www.chedong.com/phpMan.php/man/sysctl.d/5/markdown), [**sysctl**(8)](https://www.chedong.com/phpMan.php/man/sysctl/8/markdown)

systemd 255                                                                [_SYSTEMD-SYSCTL.SERVICE_(8)](https://www.chedong.com/phpMan.php/man/SYSTEMD-SYSCTL.SERVICE/8/markdown)