How can I create a launchd agent that will run only once?

Question

Since there is no "Year" parameter in the launchd plist format, how is it possible to create an agent that will run only once and not once a year?

Answer 1

Since your reference "Year", I assume you are using StartCalendarInterval. If you don't want to run at an interval, use the RunAtLoad key, which will cause it to run once each time the system starts.

<key>RunAtLoad</key>
    <true/>

Now if you truly only want the script to run once (ever), don't use launchctl at all, just run it once on the command line and be done with it.

Answer 2

Use the key LaunchOnlyOnce for this:

<key>LaunchOnlyOnce</key>
<true/>

This will launch the agent only once if the system is not rebooted.