systemctl

Updated: October 15, 2024

Systemctl is used to introspect and control the state of the “systemd”.

Control systemd system and service manager.

Table of Contents

tldr

systemctl
    -s, --signal=  #[SIGTERM, SIGINT OR SIGSTOP]
        SIGTERM- graceful shutdown, can be ignored.
        SIGINT- same as ctrl-c, process is interrupted and stopped, can be ignored.
        SIGSTOP- pauses a process, cannot be ignored.
    
    
systemctl isolate  (.target is assumed if no extension given)
    systemctl isolate runtime0.target
    sudo systemctl set-default runlevel5.target 
    systemctl list-units --type=target

RUNLEVELS

runlevel0.target halt/shutdown
runlevel1.target Single User Mode -networking -daemons -user logins
runlevel2.target Multi-user Mode - networking -daemons
runlevel3.target Multi-user Mode + networking
runlevel4.target Not Used
runlevel5.target level3+X11 (graphical.target)
runlevel6.target reboot

systemctl start foo.service       # activate a service immediately
systemctl stop foo.service        # deactivate a service immediately
systemctl restart foo.service     # restart a service
systemctl status foo.service      # check if service is running
systemctl enable foo.service      # starts service on bootup
systemctl disable foo.service     # service will not start on bootup
systemctl is-enabled foo.service; echo $?  # check if service is enabled, 0 yes, 1 no

Boot to Bios

sudo systemctl reboot --firmware        # linux