systemctl

• systemctl is the interaction with systemd
• New version of the legacy service command

Unit File Commands

• Unit locations
• /usr/lib/systemd/system/: units provided by installed packages
• /etc/systemd/system/: units installed by the system administrator
• Unit types
• .service
  • How to start or stop a service
  • When it should actually start
  • Dependencies
• .socket
  • Network, IPC socket, or FIFO buffer
  • Always have a .service associated that is started when activity is noticed on the socket
• .device
  • Depends on udev rules or sysfs
• .mount
  • Mount point to be managed
  • Entries at /etc/fstab have units created automatically
• .automount
  • Associated with a .mount
• .swap
  • Swap space on the system
• .target
  • Provide synchronization points for other units when booting up or changing states
• .path
  • A path to be used for activation
  • Uses inotify to monitor path changes
• .timer
  • Similar to a cronjob
• .snapshot
  • Allows to reconstruct the a state of the system
  • Do not survive across sessions
  • Used to roll back temporary states
• .slice
  • Associated with Linux Control Group nodes
  • Restricts access of resources by processes
• .scope
  • Created automatically based on information received from bus interfaces

enable

sudo systemctl enable "unit" # system unit (--system implied)
systemctl enable "unit" --user # user unit (local config)
systemctl enable "unit" --user --global # user unit (global config)

disable

systemctl disable "unit"

mask

• Symlinks to /dev/null

systemctl mask "systemd-rfkill.service"

list-unit-files

systemctl list-unit-files --state=masked
systemctl list-unit-files | grep masked

Unit Commands

status

# Analyzing the system state
systemctl status
systemctl status "unit" # status of a specific unit

list-units

# Checking the unit status
systemctl
systemctl list-units # same output

# filters
systemctl list-units --type=automount # auto mounted partitions
systemctl list-units --type=service
systemctl list-units --user --type=target
systemctl list-units --failed
systemctl list-units --all # loaded but inactive

start

systemctl start "unit"
systemctl start sway.service --wait --user

stop

systemctl stop "unit"

restart

systemctl restart "unit"
systemctl restart pipewire.service --user

Job Commands

list-jobs

systemctl list-jobs --user

Environment Commands

show-environment

systemctl --user show-environment

set-environment

# import import-environment variables
systemctl --user import-environment DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP
dbus-update-activation-environment --systemd DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP

# set environment variables for a service
systemctl set-environment \
  MYSQLD_OPTS="--skip-grant-tables --skip-networking"

Manager State Commands

daemon-reload

systemctl daemon-reload