Settting up PATH Environment Variables

HOW TO EDIT PATH VARIABLES IN MAC - 

1. Open terminal and enter the following command  - 

touch ~/.bash_profile; open ~/.bash_profile

This will open the bash_profile in text editor 

2. Add the following line to the end of the file adding whatever additional directory you want in your path:

export PATH="$HOME/.rbenv/bin:$PATH"

3. Save the .bash_profile file and Quit (Command + Q) Text Edit.

4. Force the .bash_profile to execute. This loads the values immediately without having to reboot. In your Terminal window, run the following command.

source ~/.bash_profile

Voila ! You are done. 
Check your Path vars by typing echo$PATH in the editor.   

Multiple path environment variable setup with bash -

export PATH="A"
export PATH="$PATH:B"
export PATH="$PATH:C"