Could anyone tell me what the second line in this block of code in this here-document does.

vi /tmp/irfelogls2.txt <<!
:%s / P/P/
:wq!
!

1. Opens file.
2. Performs command ":%s / P/P/"
3. Write, and force-quit the editor.

Hm..

I think what it's doing is, searching for a regex of " P" and then replacing it with just a "P".. correct?

Edit: Ehh.. sorry... what a waste of a post, I think I answered my own question.

ehhhh.... almost
it replaces the FIRST occurance ' P' with 'P' on every line of a file.
In order to replace ALL the occurances on all the lines:
:%s / P/P/g

ahh, i see.