User:Johannbg/QA/Systemd/Systemctl

Name
systemctl — Control the systemd system and session manager

Synopsis
systemctl [OPTIONS...] {COMMAND} [NAME...]

Description
systemctl may be used to introspect and control the state of the systemd(1) system and session manager.

Options
The following options are understood:

--help, -h Prints a short help text and exits.

--type=, -t When listing units, limit display to certain unit types. If not specified units of all types will be shown. The argument should be a unit type name such as service, socket and similar.

--property=, -p When showing unit/job/manager information, limit display to certain property names. If not specified all set properties are shown. The argument should be a property name, such as MainPID.

--all, -a When listing units, show all units, regardless of their state, including inactive units. When showing unit/job/manager information, show all properties regardless whether they are set or not.

--fail If the requested operation conflicts with an existing unfinished operation, fail the command. If this is not specified the requested operation will replace the pending job if necessary.

--system Talk to the systemd system manager. (Default)

--session Talk to the systemd session manager of the calling user.

--no-block Do not synchronously wait for the requested operation to finish. If this is not specified the job will be verified, enqueued and systemctl will wait until it is completed. By passing this argument it is only verified and enqueued.

--quiet, -q Suppress output to STDOUT for snapshot and check.

--no-wall Don't send wall message before halt, power-off, reboot.

The following commands are understood:

list-units List known units.

start [NAME...] Start one or more units specified on the command line.

stop [NAME...] Stop one or more units specified on the command line.

reload [NAME...] Asks all services whose units are listed on the command line to reload their configuration. Note that this will reload the daemon configuration itself, not the unit configuration file of systemd. If you want systemd to reload the configuration file of a unit use the daemon-reload command. In other words: for the example case of Apache, this will reload Apache's httpd.conf in the web server, not the apache.service systemd unit file.

This command should not be confused with the daemon-reload or load commands.

restart [NAME...] Restart one or more units specified on the command line. If the units are not running yet they will be started. try-restart [NAME...] Restart one or more units specified on the command line. If the units are not running yet the operation will fail.

reload-or-restart [NAME...] reload-or-try-restart [NAME...] Reload one or more units if they support it. If not restart them instead.

isolate [NAME] Start the unit specified on the command line and its dependencies and stop all others.

check [NAME...] Check whether any of the specified units is active (i.e. running). Returns 0 if at least one is active, non-zero otherwise. Unless --quiet is specified this will also print the current unit state to STDOUT.

status [NAME...] Show short status information about one or more units. This shows terse runtime information about units.

show [NAME...|JOB...] Show properties of one or more units, jobs or the manager itself. If no argument is specified properties of the manager will be shown. If a unit name is specified properties of the unit is shown, and if a job id is specified properties of the job is shown.

load [NAME...] Load one or more units specified on the command line. This will simply load their configuration from disk, but not start them. To start them you need to use the start command which will implicitly load a unit that has not been loaded yet. Note that systemd garbage collects loaded units that are not active or referenced by an active unit. This means that units loaded this way will usually not stay loaded for long. Also note that this command cannot be used to reload unit configuration. Use the daemon-reload command for that. All in all, this command is of little use except for debugging.

This command should not be confused with the daemon-reload or reload commands.

list-jobs List jobs that are in progress.

cancel [JOB...] Cancel one or more jobs specified on the command line by their numeric job IDs.

clear-jobs Cancel all jobs that are in progress.

monitor Monitor unit/job changes. This is mostly useful for debugging purposes and prints a line each time systemd loads or unloads a unit configuration file, or a unit property changes.

dump Dump server status. This will output a (usually very long) human readable manager status dump. Its format is subject to change without notice and should not be parsed by applications.

snapshot [NAME] Create a snapshot. If a snapshot name is specified, the new snapshot will be named after it. If none is specified an automatic snapshot name is generated. In either case, the snapshot name used is printed to STDOUT, unless --quiet is specified.

A snapshot refers to a saved state of the systemd manager. It is implemented itself as unit that is generated dynamically with this command and has dependencies on all units active at the time. At a later time the user may return to this state by using the isolate command on the snapshot unit.

delete [NAME...] Remove a snapshot previously created with snapshot.

daemon-reload Reload systemd manager configuration. This will reload all unit files and recreate the entire dependency tree. While the daemon is reloaded, all sockets systemd listens on on behalf of user configuration will stay accessible.

This command should not be confused with the load or reload commands.

daemon-reexec Reexecute the systemd manager. This will serialize the manager state, reexecute the process and deserialize the state again. This command is of little use except for debugging and package upgrades. Sometimes it might be helpful as a heavy-weight daemon-reload. While the daemon is reexecuted all sockets systemd listens on on behalf of user configuration will stay accessible.

daemon-exit Ask the systemd manager to quit. This is only supported for session managers (i.e. in conjunction with the --session option) and will fail otherwise.

show-environment Dump the systemd manager environment block. The environment block will be dumped in straight-forward form suitable for sourcing into a shell script. This environment block will be passed to all processes the manager spawns.

set-environment [NAME=VALUE...] Set one or more systemd manager environment variables, as specified on the command line.

unset-environment [NAME...] Unset one or more systemd manager environment variables. If only a variable name is specified it will be removed regardless of its value. If a variable and a value are specified the variable is only removed if it has the specified value.

halt Shut down and halt the system. This is mostly equivalent to start halt.target but also prints a wall message to all users.

poweroff Shut down and power-off the system. This is mostly equivalent to start poweroff.target but also prints a wall message to all users.

reboot Shut down and reboot the system. This is mostly equivalent to start reboot.target but also prints a wall message to all users.

default Enter default mode. This is mostly equivalent to start default.target.

rescue Enter rescue mode. This is mostly equivalent to isolate rescue.target but also prints a wall message to all users.

emergency Enter emergency mode. This is mostly equivalent to isolate emergency.target but also prints a wall message to all users.

Exit status

On success 0 is returned, a non-zero failure code otherwise.