From MoodleDocs

This launchd script will start a unoconv listener at boot time and restart it if it crashes. The HOME directory for the unoconv process will be set to "/tmp/" and the user will be "_www" (default apache user on OS X).

Copy this script to /Library/LaunchDaemons/unoconv.plist to install it, then run:

$ sudo launchctl load /Library/LaunchDaemons/unoconv.plist

to start it.

Here is the script.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "">
<plist version="1.0">