Conveniently, the command used is 'find'.

Usage:

find [path...] [expression]

Example:

find / -name filename.txt -print

This would look for and display the file 'filename.txt' starting in root and moving through the directories recursively. In newer operating systems '-print' is the default and is not needed.

For more information, type 'find –help' or 'man find'.<br /> Also, check out http://www.codecoffee.com/tipsforlinux/articles/21.html

– Main.FredPettis - 22 May 2009