Adding TextWrangler to the path environment
Your alias which you have configured will change the working directory in shells which support changing directory without 'cd' to the application bundle of TextWrangler.

To have an alias which opens an app, you will need to run the binary in the app bundle, usually located in Contents/MacOS. For example…

alias textwrangler=/Applications/TextWrangler.app/Contents/MacOS/TextWrangler


The binary in TextWrangler also understands arguments for passing files, which will mean that you can now edit files using the following. This won't work with every app though.

textwrangler /path/to/file


I'm not sure I understand what you're trying to add to your path, but if you want to add the binary to your path, you can add the containing folder:

export PATH=$PATH:/Applications/TextWrangler.app/Contents/MacOS


To add the alias to every interactive shell session, add the alias line to one of the profile files for your shell.