Index · Directives systemd 250


systemd-sysctl.service, systemd-sysctl — Configure kernel parameters at boot


/usr/lib/systemd/systemd-sysctl [OPTIONS...] [CONFIGFILE...]



systemd-sysctl.service is an early boot service that configures sysctl(8) 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). 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) 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.



Only apply rules with the specified prefix.


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


Do not pipe output into a pager.

-h, --help

Print a short help text and exit.


Print a short version string and exit.


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) 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) for various ways to directly apply sysctl settings.

See Also

systemd(1), sysctl.d(5), sysctl(8)