Profile files

Introduction

 Each shell has it's own way of handling script files and boot strapping your environment variables 

Different shells execute the profiles in specific orders, see  below

bash

1. Bash as login shell will load /etc/profile, ~/.bash_profile, ~/.bash_login, ~/.profile in the order
2. Bash as non-login interactive shell will load ~/.bashrc
3. Bash as non-login non-interactive shell will load the configuration specified in environment variable $BASH_ENV

The /etc/profile script will iterate through /etc/profile.d/ directory running each .sh file in that directory when you open a shell window. So simply create a new .sh file in /etc/profile.d/ with any environment variables you want to give all users.