Hi Gurus:
I am trying to understand the following line of code.I did enough of googling to understand but no luck.Please help me understand the follow chunk of code:

X=$0
MOD=${X%/*}/env.ksh

X is the current script from which I am trying to execute.

Say if X=test.ksh

$MOD is echoing : test.ksh/env.ksh

What I am trying to understand is,What exactly is {X%/*} doing.

Thanks in advance