$PATH

https://linuxacademy.com/cp/courses/lesson/course/1575/lesson/2/module/161

• colon separated
• adding a script to the /bin directory makes sure you can run it without adding ./

A Mac will compose the PATH variable by looking at these files in this order:

1. ~/.bashrc (this is read everytime a new shell is opened)
2. ~/.bash_profile (this is read only at login)
3. ~/.profile