Ubuntu Unleashed

I just ran accross a nice site www.go2linux.org the admin left a nice comment about my layout and content, thankyou.. while browsing his site I found some great content on 25 usefull linux commands I definately use daily, the author added 7 of his favorites
Check it out here
Id like to add a few commands I use as well.

htop: nice looking top for process and memory stats.
id: to check which user groups you belong to
whoami: check which user you are in a multi-user environment
echo;
example: echo * in your current directory to show you files if somehow you deleted ls - lol
example: echo whatever >>/etc/network/interfaces
cat: I like cat because I paste scripts and code right into the terminal like this:
cat >>file
type stuff/paste stuff here
cat file
root@ion:~# cat file
type stuff/paste stuff here
root@ion:~#

Resources:
linuxcommand.org

btw, feel free to share your advanced bash hacks/commands here