Systemd systemctl

Example

• cat /etc/systemd/system/chat.service

[Unit]
Description=chat service
After=network.target syslog.target

[Service]
Type=simple
ExecStart=/bin/bash -c "/bin/netcat -l -p 3333 > /tmp/chat.log"
User=root

[Install]
WantedBy=multi-user.target

Systemctl

Edit

• systemctl edit chat.service --full

Reload

• systemctl daemon-reload

Start

• systemctl start chat.service

Stop

• systemctl stop chat.service

Enable

• systemctl enable chat.service

Created symlink from /etc/systemd/system/multi-user.target.wants/chat.service to /etc/systemd/system/chat.service.

Disable

• systemctl disable chat.service

Removed symlink /etc/systemd/system/multi-user.target.wants/chat.service.

Reload

• systemctl reload chat.service

Restart

• systemctl restart chat.service

Is enabled

• systemctl is-enabled chat.service

disabled

Mask

• systemctl mask apache2.service

Created symlink from /etc/systemd/system/apache2.service to /dev/null.

Umask

• systemctl unmask apache2.service

Removed symlink /etc/systemd/system/apache2.service.

Status

• systemctl status chat.service

● chat.service - chat service
   Loaded: loaded (/etc/systemd/system/chat.service; disabled; vendor preset: enabled)
   Active: active (running) since Di 2017-10-24 16:20:26 CEST; 17s ago
 Main PID: 10949 (bash)
   CGroup: /system.slice/chat.service
           ├─10949 /bin/bash -c /bin/netcat -l -p 3333 > /tmp/chat.log
           └─10951 /bin/netcat -l -p 3333

Okt 24 16:20:26 bajor.xinux.lan systemd[1]: Started chat service.

List Dependencies

• systemctl list-dependencies apache2

apache2.service
● ├─system.slice
● ├─network-online.target
● │ ├─networking.service
● │ └─NetworkManager-wait-online.service
● └─sysinit.target
●   ├─apparmor.service
●   ├─brltty.service
●   ├─console-setup.service
...

List Units

• systemctl list-units

UNIT                                                                                                LOAD   ACTIVE SUB       DESCRIPTION
proc-sys-fs-binfmt_misc.automount                                                                   loaded active running   Arbitrary Executable File Formats File System Automount Point
sys-devices-LNXSYSTM:00-LNXSYBUS:00-PNP0A08:00-device:02-ATK0110:00-hwmon-hwmon1.device             loaded active plugged   /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:02/ATK0110:00/hwmon/hwmon1
sys-devices-pci0000:00-0000:00:01.0-0000:01:00.0-hwmon-hwmon0.device                                loaded active plugged   /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/hwmon/hwmon0
...

List Unit Files

• systemctl list-unit-files

UNIT FILE                                  STATE   
proc-sys-fs-binfmt_misc.automount          static  
dev-hugepages.mount                        static  
dev-mqueue.mount                           static  
mnt-data.mount                             enabled 
mnt-media.mount                            enabled 
proc-fs-nfsd.mount                         static  
proc-sys-fs-binfmt_misc.mount              static  
run-rpc_pipefs.mount                       static  
sys-fs-fuse-connections.mount              static  
sys-kernel-config.mount                    static  
sys-kernel-debug.mount                     static  
acpid.path                                 enabled 
cups.path                                  enabled 
systemd-ask-password-console.path          static  
systemd-ask-password-plymouth.path         static  
systemd-ask-password-wall.path             static  
systemd-networkd-resolvconf-update.path    static  
accounts-daemon.service                    enabled 
acpid.service                              disabled
...

Failed

• systemctl --failed

0 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

Isolate Halt

• systemctl isolate halt

Poweroff

• systemctl poweroff

Suspend

• systemctl suspend

Hibernate

• systemctl hibernate

List Timers

• systemctl list-timers

NEXT                         LEFT          LAST                         PASSED       UNIT                         ACTIVATES
Di 2017-10-24 21:12:15 CEST  4h 26min left Di 2017-10-24 14:01:54 CEST  2h 44min ago apt-daily.timer              apt-daily.service
Mi 2017-10-25 14:31:55 CEST  21h left      Di 2017-10-24 14:31:55 CEST  2h 14min ago systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
Mo 2017-10-30 03:05:56 CET   5 days left   Di 2017-10-24 14:36:05 CEST  2h 10min ago snapd.refresh.timer          snapd.refresh.service
n/a                          n/a           Di 2017-10-24 14:18:24 CEST  2h 27min ago ureadahead-stop.timer        ureadahead-stop.service

4 timers listed.
Pass --all to see loaded but inactive timers, too.

List Sockets

• systemctl list-sockets

systemctl list-sockets
LISTEN                          UNIT                            ACTIVATES
/dev/rfkill                     systemd-rfkill.socket           systemd-rfkill.service
/run/acpid.socket               acpid.socket                    acpid.service
/run/dmeventd-client            dm-event.socket                 dm-event.service
/run/dmeventd-server            dm-event.socket                 dm-event.service
/run/lvm/lvmetad.socket         lvm2-lvmetad.socket             lvm2-lvmetad.service
/run/lvm/lvmpolld.socket        lvm2-lvmpolld.socket            lvm2-lvmpolld.service
...

Set Target

• systemctl -f enable multi-user.target
• systemctl -f enable graphical.target