How to backout a P4 changelist

If a check-in of changelist , had edited a.c, b.h,

1. p4 sync @
2. p4 edit //depot/a.c //depot/b.h
3. p4 sync
4. p4 resolve -ay
5. p4 submit

Of course, there can be mix and match. I CL# contained a.c, b.h, c.txt, d.macro,
the above set of operations will maintain the changes for c.txt and d.macro, which may be intended.

For more on the same topic refer to
http://kb.perforce.com/?article=014

How to get rid of annoying gnome-help due to unintentionally pressing F1

Ubuntu -
1. Go to System - Preferences - Keyboard Shortcuts
2. Create a new shortcut. Name it 'do nothing', and write 'false' (without quotes) in the "command" field. Push ok.
3. Scroll to the bottom of the list and find your new command. Click on the "Disabled", on the right, and push F1.

Sharing screen across users

1. chmod +s /usr/bin/screen
2. Ctrl+a then :multiuser on
3. Ctrl+a: acladd username
4. screen -list /sessionName
screen -x /sessionName

Useful tuorial on screen
http://news.softpedia.com/news/GNU-Screen-Tutorial-44274.shtml