Bash Tests
Mon, 05/10/2010 - 00:46 — sandip(via mywiki.wooledge.org)
The test application, also known as [, is an application that usually resides somewhere in /usr/bin or /bin and is used a lot by shell programmers to perform certain tests on variables. In a number of shells, including bash, [ is implemented as a shell builtin.
Difference between test, "[" and "[[":
http://mywiki.wooledge.org/Bas