systemctl Cheat Sheet: Manage systemd Services

Q: What is the difference between systemctl enable and start?

start runs the service now; enable makes it start automatically at boot. systemctl enable --now name does both.

Q: How do I list all running services?

systemctl list-units --type=service --state=running . For every installed service and whether it is enabled, use systemctl list-unit-files --type=service .

Q: What is the difference between restart and reload?

restart stops and starts the process. reload asks the running process to re-read its configuration without dropping connections, if the service supports it. reload-or-restart picks reload when available.

Q: Do I need daemon-reload after editing a unit file?

Yes, after editing files in /etc/systemd/system/ by hand run sudo systemctl daemon-reload . systemctl edit does it for you.

Q: How do I prevent a service from ever starting?

sudo systemctl mask name links the unit to /dev/null so nothing can start it, not even as a dependency. Undo with unmask .

Most used

systemctl status nginx                 # is it running? recent log lines
sudo systemctl restart nginx           # restart now
sudo systemctl enable --now nginx      # start now and at every boot
systemctl --failed                     # what is broken?
sudo systemctl edit nginx              # override settings with a drop-in
journalctl -u nginx -e                 # full logs for the unit

systemctl controls systemd, the init system and service manager on Ubuntu, Debian, Fedora, Arch, openSUSE and Mint. Read-only commands work as a normal user; changing state needs sudo. The .service suffix is optional for services. For the concepts behind units and targets, see the systemd basics guide.

Start, stop and restart

Command	What it does
`sudo systemctl start name`	Start a unit now
`sudo systemctl stop name`	Stop it now
`sudo systemctl restart name`	Stop then start
`sudo systemctl try-restart name`	Restart only if it is already running
`sudo systemctl reload name`	Re-read config without restarting (if the service supports it)
`sudo systemctl reload-or-restart name`	Reload if possible, otherwise restart
`sudo systemctl kill name`	Send SIGTERM to all processes of the unit
`sudo systemctl kill -s SIGKILL name`	Force-kill a hung service
`sudo systemctl reset-failed name`	Clear the failed state and start-rate counter
`sudo systemctl start a b c`	Act on several units at once

Enable at boot

Command	What it does
`sudo systemctl enable name`	Start at boot (creates symlinks per the `[Install]` section)
`sudo systemctl enable --now name`	Enable and start immediately
`sudo systemctl disable name`	Don't start at boot
`sudo systemctl disable --now name`	Disable and stop immediately
`sudo systemctl mask name`	Make the unit impossible to start
`sudo systemctl unmask name`	Undo `mask`
`sudo systemctl reenable name`	Disable and enable again (after changing `[Install]`)
`systemctl is-enabled name`	Prints enabled, disabled, static, masked…

Status and inspection

Command	What it does
`systemctl status name`	State, main PID, memory, last log lines
`systemctl status name -l --no-pager`	Full lines, no pager (good for pasting)
`systemctl is-active name`	Prints active / inactive / failed; exit code 0 if active
`systemctl is-failed name`	Exit code 0 if the unit failed
`systemctl cat name`	Show the unit file and all drop-ins in effect
`systemctl show name`	All properties, machine-readable
`systemctl show name -p MainPID,ActiveState,Restart`	Selected properties only
`systemctl list-dependencies name`	What the unit pulls in
`systemctl list-dependencies --reverse name`	What depends on the unit
`systemd-analyze verify /etc/systemd/system/app.service`	Check a unit file for errors
`systemd-analyze security name`	Score a service's sandboxing options

When status shows failed or a start command prints Job for X.service failed, the reason is in the journal: see the journalctl cheat sheet.

Listing units

Command	What it does
`systemctl`	All loaded and active units (same as `list-units`)
`systemctl --failed`	Units in the failed state
`systemctl list-units --type=service`	Loaded services
`systemctl list-units --type=service --state=running`	Running services only
`systemctl list-units --all`	Include inactive units
`systemctl list-unit-files --type=service`	Every installed service with its enable state
`systemctl list-unit-files --state=enabled`	Everything that starts at boot
`systemctl list-units 'docker*'`	Filter by a glob pattern
`systemctl list-sockets`	Socket-activated units and their listening addresses
`systemctl list-timers --all`	Timers with last and next run times

Editing unit files

Unit files shipped by packages live in /usr/lib/systemd/system/ (or /lib/systemd/system/). Never edit them; package updates overwrite them. Put your changes in /etc/systemd/system/, which takes precedence.

Command	What it does
`sudo systemctl edit name`	Create or edit a drop-in `override.conf` (only override what you change)
`sudo systemctl edit --full name`	Copy the whole unit to `/etc/systemd/system/` and edit it
`sudo systemctl edit --force --full new.service`	Create a brand-new unit file
`sudo systemctl revert name`	Remove your overrides and go back to the vendor unit
`sudo systemctl daemon-reload`	Reload unit files after editing them by hand
`systemd-delta`	List all overridden and extended units on the system
`sudo SYSTEMD_EDITOR=vim systemctl edit name`	Choose the editor (or set `EDITOR`)

Targets, power and system state

Command	What it does
`systemctl get-default`	Boot target (graphical.target or multi-user.target)
`sudo systemctl set-default multi-user.target`	Boot to text mode (no desktop)
`sudo systemctl isolate multi-user.target`	Switch to a target now (stops the desktop)
`sudo systemctl rescue`	Single-user rescue mode
`sudo systemctl emergency`	Emergency shell (see You are in emergency mode)
`sudo systemctl reboot` / `poweroff`	Reboot or power off
`systemctl suspend` / `hibernate`	Sleep states
`sudo systemctl soft-reboot`	Restart userspace without rebooting the kernel
`systemctl is-system-running`	running, degraded (some unit failed), starting…

User services and remote hosts

Command	What it does
`systemctl --user status name`	Manage your own per-user units (no sudo)
`systemctl --user enable --now name`	Enable a unit from `~/.config/systemd/user/`
`systemctl --user restart pipewire wireplumber`	Restart the user audio stack
`sudo loginctl enable-linger alice`	Keep alice's user services running when she is logged out
`systemctl -H user@host status nginx`	Query another machine over SSH

Common recipes

Create a simple service for your own script:

sudo systemctl edit --force --full myapp.service

[Unit]
Description=My app
After=network-online.target
Wants=network-online.target

[Service]
User=myapp
ExecStart=/opt/myapp/run.sh
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

sudo systemctl enable --now myapp
systemctl status myapp

Raise a service's open-file limit (a common fix for Too many open files):

sudo systemctl edit nginx
# add:
#   [Service]
#   LimitNOFILE=65535
sudo systemctl restart nginx
systemctl show nginx -p LimitNOFILE

Find and fix every failed unit after boot:

systemctl --failed
journalctl -b -u failed-unit-name --no-pager | tail -50
sudo systemctl reset-failed

Make a service restart automatically when it crashes:

sudo systemctl edit myapp
#   [Service]
#   Restart=always
#   RestartSec=3

Find which service owns a process or a port:

systemctl status 1234          # by PID
sudo ss -tlnp | grep ':80 '    # PID of the listener, then systemctl status PID

Replace a cron job with a timer: see cron vs systemd timers or convert a line automatically with the cron to systemd timer converter.

Gotchas

Enabled is not running. enable only affects the next boot. Use enable --now or follow it with start.
Forgot daemon-reload. After editing a unit file directly, systemctl warns "unit file changed on disk". Run sudo systemctl daemon-reload before restarting.
Clearing a list setting in a drop-in. To replace ExecStart in an override you must first empty it with a blank ExecStart= line, then set the new value; otherwise systemd complains about multiple ExecStart lines.
Unit names differ between distros. SSH is ssh on Debian/Ubuntu and sshd elsewhere; Apache is apache2 on Debian/Ubuntu and httpd on Fedora/openSUSE. Use systemctl list-unit-files | grep -i name.
"static" units can't be enabled. They have no [Install] section and are started by another unit, socket or timer.
Start limit hit. A service that crashes repeatedly is blocked with "start request repeated too quickly". Fix the cause, then reset-failed.
--user needs a user session. Through sudo or su there is often no user bus; log in as that user, or use systemctl --user -M alice@.

Reference: systemctl(1), systemd.service(5).

Frequently asked questions

What is the difference between systemctl enable and start?

start runs the service now; enable makes it start automatically at boot. systemctl enable --now name does both.

How do I list all running services?

systemctl list-units --type=service --state=running. For every installed service and whether it is enabled, use systemctl list-unit-files --type=service.

What is the difference between restart and reload?

restart stops and starts the process. reload asks the running process to re-read its configuration without dropping connections, if the service supports it. reload-or-restart picks reload when available.

Do I need daemon-reload after editing a unit file?

Yes, after editing files in /etc/systemd/system/ by hand run sudo systemctl daemon-reload. systemctl edit does it for you.

How do I prevent a service from ever starting?

sudo systemctl mask name links the unit to /dev/null so nothing can start it, not even as a dependency. Undo with unmask.

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