Cheatsheet Pages / systemd Cheatsheet
How to control whether a service starts at boot — systemctl enable / disable
Boot-time behaviour only: enable makes it start on boot, disable stops that — neither starts or stops it right now.
Most management commands need sudo, and systemctl only works on a system actually booted with systemd — inside containers it fails with “System has not been booted with systemd as init system”. Every command was checked against systemd 255, and the example units pass systemd-analyze verify.
sudo systemctl enable nginx # create the boot symlink — does NOT start the service now
sudo systemctl disable nginx # remove the symlink — does NOT stop a running service
# the classic trap: enable ≠ start. A freshly enabled service only comes up at next boot.