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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CREDENTIALS | EXAMPLES | SEE ALSO | COLOPHON |
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SYSTEMD-SYSCTL.SERVICE(8) systemd-sysctl.serviceSYSTEMD-SYSCTL.SERVICE(8)
systemd-sysctl.service, systemd-sysctl - Configure kernel
parameters at boot
/usr/lib/systemd/systemd-sysctl [OPTIONS...] [CONFIGFILE...]
systemd-sysctl.service
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.
--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.
systemd-sysctl supports the service credentials logic as
implemented by ImportCredential=/LoadCredential=/SetCredential=
(see systemd.exec(5) 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.
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.
systemd(1), sysctl.d(5), sysctl(8)
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SYSTEMD-SYSCTL.SERVICE(8)
Pages that refer to this page: sysctl.conf(5), sysctl.d(5), systemd.directives(7), systemd.index(7), systemd-coredump(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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