Cool CUI!

Run the last command as root
$ sudo !!

Save a file you edited in vi without the needed permissions. i know how it is like when you change something and at last realize that u cant save it.
$ :w !sudo tee %

Mount a temporary ram partition for a blazing read-write. But this will be wiped off once you restart your box. OR when u need extra space!
$ mount -t tmpfs tmpfs /mnt -o size=1024m

wanna downoad an entire website?
$ wget –random-wait -r -p -e robots=off -U mozilla

Shutdown a windows PC from a linux box. ( requires a samba package )
$ net rpc shutdown -I ipAddressOfWindowsPC -U username%password

List the size (in human readable form) of all sub folders from the current location
$ du -h –max-depth=1

Jump to a directory, execute a command and jump back to current dir
$ (cd /tmp && ls)

Remind yourself to leave in 15 minutes
$ leave +15

what is an app doing?
$ diff <(lsof -p 1234) <(sleep 10; lsof -p 1234)