Reloading all code from the Erlang shell

One of the reasons Erlang is pretty cool is that it supports hot code reloading. With OTP (Open Telecom Platform) applications, this can be done through a complicated mechanism involving release files, code_change callbacks to update state, and special upgrade/downgrade scripts.

In development, however, that's a bit of a nuisance. So, how do you simply reload all of the loaded modules after you've recompiled them? Here's a quick solution to paste into your ~/.erlang:

Reload = fun(M) ->
                 code:purge(M),
                 code:soft_purge(M),
                 {module, M} = code:load_file(M),
                 {ok, M}
         end.
 
ReloadAll =
 fun() ->
         Modules = [M || {M, P} <- code:all_loaded(), is_list(P) andalso string:str(P, "/home/amiest") > 0],
         [Reload(M) || M <- Modules]
 end.

Obviously, replace /home/amiest with a directory within which your modules reside. Then, simply run ReloadAll(). from the shell to load the newest versions of your modules.