sed is great for pattern matching or retrieving linesHere is a cool example
Say you type df:
The output would be something like:
[quote:3bb8d51437]Filesystem 1k-blocks Used Available Use% Mounted on
/dev/hda2 1712432 1206664 418780 75% /
/dev/hda1 31201 10505 19085 36% /boot
none 30932 0 30932 0% /dev/shm
[/quote:3bb8d51........