Systemd

Systemd reminder

Command line#

Common#

The --user option limit command on the user scope

The --system option do the same but for the system and is the default.

The user systemd unit file can be found in :

• ~/.local/share/systemd/user/
• ~/.config/systemd/user/

Get system status#

$ systemctl status

List all units in running state#

$ systemctl list-units --state running

List all failed units#

$ systemctl --failed

Get a list of all installed units#

$ systemctl list-unit-files

Get unit status#

$ systemctl status $(UNIT_NAME)

Start unit#

$ systemctl start $(UNIT_NAME)

Stop unit#

$ systemctl stop $(UNIT_NAME)

Restart unit#

$ systemctl restart $(UNIT_NAME)

Reload unit#

$ systemctl reload $(UNIT_NAME)

Check if unit is enabled#

$ systemctl is-enabled $(UNIT_NAME)

Enable unit at boot#

$ systemctl enable $(UNIT_NAME)

Disable unit#

$ systemctl disable $(UNIT_NAME)

Mask a given unit#

$ systemctl mask $(UNIT_NAME)

Unmask a given unit#

$ systemctl unmask $(UNIT_NAME)

List all timer#

$ systemctl list-timers

Reload the systemd manager configuration#

Usefull when you change or create an unit file

$ systemctl daemon-reload

Show cgroups ressources usage#

$ systemd-cgtop

Show ressources of given cgroup#

$ systemd-cgls $(CGROUP)

Systemd unit management

Create service unit
-------------------

The unit name must be finish by .service for example : **my-greatest-unit.service**.
The units path location are in **/etc/systemd/system/** or **/lib/systemd/system/**.
For new units **/etc/systemd/system/** is the better location.

```bash
   [Unit]
   Description=$(UNIT_DESCRIPTION)
   After=$(AFTER_WHICH_TARGET)

   [Service]
   Type=$(SYSTEMD_TYPE)
   User=$(USER)
   ExecStartPre=$(PRE_EXEC)
   ExecStart=$(EXEC_COMMAND)
   ExecStop=$(EXEC_COMMAND)
   Restart=$(RESTART POLICY)
```

Types :

* ``simple``
* ``forking``
* ``oneshot``
* ``dbus``
* ``notify``
* ``idle``