Confusion about rake assets:clean / cleanup on the asset pipeline in rails

Note: This answer is rails 3 specific. For rails 4 and later, look at other answers here.

If you precompile on your local machine, then you can commit these generated assets into the repository and proceed with deployment. No need to compile them on production machine.

But it introduces a problem: now when you change source files (coffescript / scss), the app won't pick up the changes, because it will serve precompiled files instead. rake assets:clean deletes these precompiled files.

In my projects assets are precompiled as a part of deployment. Capistrano makes it very easy.

Also, I never heard of rake assets:cleanup.

Run rake assets:clobber to actually clean the assets.http://www.dixis.com/?p=735

Sergio's answer was completely correct in Rails 3. rake assets:clean deleted all assets that had been previously precompiled into the public/assets directory.

In Rails 4, you run rake assets:clobber to do the same thing.

If you run rake assets:precompile with the following config (by default turned on in staging and production):

# config/environments/production.rbconfig.assets.digest = true

You compiled assets get timestamped. This means you can compile your new assets while leaving the old assets in place. You usually want to do this in production so you website will still access the old files while your running precompile to create your new files (because you've added new css/javascript). You now want to get rid of the old files that are no longer in use. The clean it removes the old versions of the precompiled assets while leaving the new assets in place.