Reloader is the fantastic reloader.erl from mochiweb packaged into an application. Use reloader during development to automatically reload modules when they are compiled. It also re-runs tests if the test/0 method is exported.
If you're using rebar (try it, it's great - http://hg.basho.com/rebar/wiki/Home), you can add this to you rebar.config:
{deps, [
{reloader, "0.1", {git, "http://github.com/bjnortier/reloader.git", "master"}}
}
then:
application:start(reloader).
Otherwise you can build it with:
$./rebar compile
and add to you load path with using your preferred method.