PATH Configuration – How to Add gedit to Your PATH in macOS

Test the output of uname; it will be Darwin on OS X and Linux on Linux.

if [[ $(uname) == Darwin ]]; then
    export PATH="$HOME/SW/bin_mac:$PATH"
fi

Alternately, you could just add an appropriate directory on each machine, which will be useful if you find yourself needing a separate Linux bin directory as well in the future.

export PATH="$HOME/SW/bin_$(uname):..."

and either mv or ln -s your bin_mac to bin_Darwin; then you can create a bin_Linux directory in the future if you need it, and it'll just work.

(You could also test $HOSTTYPE, which is set by bash, but it contains more information than you're likely to need.)

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.