You can easily add the Applications directory to your PATH but it will not do anything useful as it is a collection of OSX apps which are bundles and can't be run from the command line.
There are several alternatives
- Use the open command which will open any OSX app e.g.
open -a Sublime\ Text.app source.php
This works for all apps - Find the unix executable in the app bundle usually in Contents/MacOS and with a similar name to the app. In Sublime this looks like sublime.py a python file
- Some apps e.g. Sublime provide a specific command line tool and use that. This is what is suggested in Sublime's documentation However I would just create an alias to the full path
"/Applications/Sublime Text 2.app/Contents/SharedSupport/bin/subl"
and use the full path in the EDITOR environment variable