systemd-suspend.servicesystemdDeveloperLennartPoetteringlennart@poettering.netsystemd-suspend.service8systemd-suspend.servicesystemd-hibernate.servicesystemd-hybrid-sleep.servicesystemd-sleepSystem sleep state logicsystemd-suspend.servicesystemd-hibernate.servicesystemd-hybrid-sleep.service/usr/lib/systemd/systemd-sleepDescriptionsystemd-suspend.service is
a system service that is pulled in by
suspend.target and is responsible
for the actual system suspend. Similarly,
systemd-hibernate.service is
pulled in by hibernate.target to
execute the actual hibernation. Finally,
systemd-hybrid-sleep.service is
pulled in by hybrid-sleep.target
to execute hybrid hibernation with system
suspend.Immediately before entering system suspend
and/or hibernation
systemd-suspend.service (and the
other mentioned units, respectively) will run all
executables in
/usr/lib/systemd/system-sleep/
and pass two arguments to them. The first argument
will be pre, the second either
suspend,
hibernate, or
hybrid-sleep depending on the
chosen action. Immediately after leaving system
suspend and/or hibernation the same executables are run,
but the first argument is now
post. All executables in this
directory are executed in parallel, and execution of
the action is not continued until all executables
have finished.Note that scripts or binaries dropped in
/usr/lib/systemd/system-sleep/
are intended for local use only and should be
considered hacks. If applications want to be notified
of system suspend/hibernation and resume, there are
much nicer interfaces available.Note that
systemd-suspend.service,
systemd-hibernate.service, and
systemd-hybrid-sleep.service
should never be executed directly. Instead, trigger
system sleep states with a command such as
systemctl suspend or
similar.Internally, this service will echo a string like
mem into
/sys/power/state, to trigger the
actual system suspend. What exactly is written
where can be configured in the [Sleep]
section of /etc/systemd/sleep.conf.
See systemd-sleep.conf5.
Optionssystemd-sleep understands the
following commands:Print a short help
text and exit.Print the systemd version
identifier and exit.Suspend, hibernate, or
put the system to hybrid sleep.See Alsosystemd-sleep.conf5,
systemd1,
systemctl1,
systemd.special7,
systemd-halt.service8