In order to do anything in Linux, you must:

In order to do anything in Linux, you must:

• start an application
• use/run a command or script
• point & click to an icon
• do something to get the system to work for you

As far as Linux is concerned, all of the above and anything and everything that is happening at any point in time causes a "process" to execute or activate.

Upon logging in to the system, you actually end up starting several processes:

• login process (X or otherwise)
• authentication process (may include PAM)
• shell process once authenticated (usually BASH)
• login scripts (/etc/profile scripts, ~/.bash_profile, etc)