I was just trying to understand Exec a bit better, specifically in scripting. I went down a small rabbit hole, and I’m not sure I’m any closer to understanding the purpose of exec in scripting yet, but I just had a lightbulb that I figured I should write down. My objective is to show the relationship between fork and exec, and what exec’s purpose is. Let’s start with some random process.

Processes states that ps indicate are: D Uninterruptible sleep (usually IO) R Running or runnable (on run queue) S Interruptible sleep (waiting for an event to complete) T Stopped, either by a job control signal or because it is being traced. W paging (not valid since the 2.6.xx kernel) X dead (should never be seen) Z Defunct ("zombie") process, terminated but not reaped by its parent. and the additional characters are: