systemd cheat sheets

050.systemctl_cheat_sheet.txt

# reload the systemd deamon config files (useful for testing once you have made a change)
systemctl daemon-reload

# list all unit configuration files found in the search paths.
systemctl list-unit-files

# list specific unit files
systemctl list-unit-files | grep -iE 'unit-name-1|unit-name-2|unit-name-3'

# list units with descriptions which are currently loaded into memory
systemctl list-units

# lists units with additional information
systemctl list-units --all

# list failed services
systemctl list-units --type=service --state=failed

# list disabled services
systemctl list-units --type=service --state=disabled

# list failed - generic
systemctl --failed

# list running services
systemctl list-units --type=service --state=running

# list enabled services
systemctl list-unit-files --type=service --state=enabled 

# display enabled /disabled status of single unit
systemctl is-enabled <servicename>
  output explanation - enabled   :  service is enabled and set to start at boot
                     - disabled  :  service is disabled and won't start at boot
                     - static    :  service is enabled but will not start at boot

# display active / inactive status of single unit
systemctl is-enabled <servicename>
  output explanation - active
                     - inactive

# find the paths of installed unit files using the locate command (may require install of plocate)
locate '*.service'

# find the paths of installed unit files within /etc/ and /var/ using the find command (may be slower)
find /etc /var -type f -name '*.service'

050.systemd_boot_time_cheatsheet.txt

# list how long boot takes
systemd-analyze

# show which parts take how long to boot
systemd-analyze blame

050.systemd_settings_cheatsheet.txt

# run directory setting when you login for a user - below is the default
/etc/systemd/logind.conf -> [Login] -> RuntimeDirectorySize=10% 

050.systemd_unit_override_cheatsheet.txt

# show the path the actual overide file : 
systemctl show --property=DropInPaths <unit-name>

# show all set values for a unit : 
systemctl show <unit-name>

# edit the overide file for a unit
sudo systemctl edit <unit-name>

# reload the systemd datrabase after editing overide files 
systemctl daemon-reload

050.transient_scopes_cheatsheet.txt

# start a process with a memory limit
systemd-run --user --scope -p MemoryMax=8g -p MemorySwapMax=8G <executable>

# check on scope status
systemctl --user status run-*.scope

# reset a failed scope
systemctl --user reset-failed run-*.scope

050.unit_files_cheatsheet.txt

[Unit]

# require another unit 
Requires=<unit.target>

# specify the order
After=<unit.target>
Before=<unit.target>

# ---------------------------------------------

[Service]
# Restart on failure with a delay
Restart=on-failure
RestartSec=10   # Set the delay in seconds


[Service]
# Startup delay
ExecStartPre=/bin/sleep 10

090.loginctl_cheat_sheet.txt

# show information focused on linger / state for a particular users login units / timers etc...
loginctl show-user <user> | grep -E "Linger|Sessions|State"

# show information about a user and if Linger is enabled
loginctl show-user $USER | grep Linger
ls /var/lib/systemd/linger/

# show user session status
loginctl list-users

# disable linger for your account
loginctl disable-linger $USER

# enable linger for your account
loginctl enable-linger $USER

090.systemctl_managing_user_units_cheat_sheet.txt

# start a job in user space which runs every 30 seconds and prints the date into a file (this unit is called jobe)
# use systemctl to stop timers like this or other kinds of units *see below
# use systemctl to show information about timers and other kinds of units * see below
systemd-run --user --on-active=1  --on-unit-active=30 --unit=job bash -c 'date >> /tmp/date.log'


# reset failed unit / and timer called 'job' by name (user - not system)
systemctl --user reset-failed job.service
systemctl --user reset-failed job.service


# stop unit called 'job (user - not system)
systemctl --user stop job.timer
systemctl --user stop job.service


# show details about a timer called 'job' started with systemctl-run
systemctl --user show job.timer

z_helpful_links_and_references.txt

# cgroups gist : 
https://gist.github.com/henri/25a6023475b23d95a253b6567ac5320f