launchctl

A command-line interface to Apple's launchd manager for launch daemons (system-wide services) and launch agents (per-user programs). launchd loads XML-based *.plist files placed in the appropriate locations, and runs the corresponding commands according to their defined schedule.

• Activate a user-specific agent to be loaded into launchd whenever the user logs in:

launchctl load ~/Library/LaunchAgents/{{my_script}}.plist

• Activate an agent which requires root privileges to run and/or should be loaded whenever any user logs in (note the absence of ~ in the path):

sudo launchctl load /Library/LaunchAgents/{{root_script}}.plist

• Activate a system-wide daemon to be loaded whenever the system boots up (even if no user logs in):

sudo launchctl load /Library/LaunchDaemons/{{system_daemon}}.plist

• Show all loaded agents/daemons, with the PID if the process they specify is currently running, and the exit code returned the last time they ran:

launchctl list

• Unload a currently loaded agent, e.g. to make changes (note: the plist file is automatically loaded into launchd after a reboot and/or logging in):

launchctl unload ~/Library/LaunchAgents/{{my_script}}.plist

• Manually run a known (loaded) agent/daemon, even if it isn’t the right time (note: this command uses the agent's label, rather than the filename):

launchctl start {{my_script}}

• Manually kill the process associated with a known agent/daemon, if it's running:

launchctl stop {{my_script}}