Created: 2008-12-23 05:05
Updated: 2017-11-26 04:10



I've got a PhD in launchd, and I'm not afraid to use it!


LaunchDoctor is really simple. It is essentially an easy interface to launchd's property list files.

There are three ways to use LaunchDoctor - the simplest being directly creating property lists and treating them as hashes:

require 'launchdr'
plist = "name.elliottcable.launchdr.test"
plist[:program_arguments] = ['/Applications/']
plist.dump LaunchDr::Launchd::Paths[:user_agent]

The second is to use the common block idiom, provided by the LaunchDr() method:

require 'launchdr'
LaunchDr "name.elliottcable.launchdr.test" do |plist|
  plist[:program_arguments] = ['/Applications/']

LaunchDoctor will automatically add the property list to launchctl, and then start it running. Once you run the above snippet, the target will immediately be launched for the first time.

LaunchDoctor can write (dump) the property lists to any place on your disk, but the idiom method assumes you're going to want to use one of the directories that launchd checks for property lists. These are stored in the Launchd::Paths array. The default is to place it in the user-owned agents directory at ~/Library/LaunchAgents.

LaunchDoctor also preforms some 'prettification' on the keys provided by launchd's property list structure. All of the keys on the launchd.plist manpage are available, but they can also be used as true 'Ruby-ish' symbol keys. All of the following are legal:

plist["UserName"] = "elliottcable"
plist[:UserName] = "elliottcable"
plist[:user_name] = "elliottcable"

Finally, you can use the Rake task interface to the last method. It simply wraps the last method inside a rake task. This method is really great if you want to provide a way to let users make your gem's binary run all the time:

require 'launchdr/task' :launchd, :bin => 'jello', :arguments => ['-D', 'shortener', 'grabup']

This isn't very flexible, but it's not very complicated either. If you need more control over the plist, just use the second method inside a task block. This method defaults to making your gem's binary run_at_load and be keep_alive as well, so it won't die.


  • Plist - gem install plist
  • Ruby Facets - gem install facets
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