When using bash, you can customize the usage environment to your linking.
bash_profile
It is executed once at login. For example, it will be loaded when you start the terminal app. You should set an environment variable(a variable declared by export) to what should be specifically set in this file.
.bashrc
It is executed once at shell startup. If you hit bash on the command line, .bashrc will be read again.(.bash_profile is not read). If you want to set it each time you start the shell, put the settings in this file.
You may want to set aliases, shell functions, and command line completion for what to set specifically in this file.
~/.bash_profile
~/.bashrc
