=====Wikimageddon=====

**echo $?** displays ending value of last program run.

**pwd** Utility that shows your current working directory.


**ldd** Displays all files linked to an executable.

**less** useful unix pager

**head** In unix displays begining of file

**tail** In Unix displays end of file

** grep ** In Unix displays parts of file with a specific pattern

Quoting Matt Haas"
 Symbol 	Description
* 	match 0 or more characters
? 	match exactly one character
[ ] 	character class - match any of the enclosed characters.
[^ ] 	inverted character class - do not match any of the enclosed characters. 

"

** wc utility word count