Thread: Config Parameter Expansion - How does it works?

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Old 05-07-2009, 07:38 PM
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If postfix_enable is defined AND NOT EMPTY, use postfix_enable value; otherwise, use "NO". Try it the following at terminal:
Code:
vech="BUS"
echo $vech
echo ${vech:="CAR"}
vech=""
echo ${vech:="CAR"}
if vech is not defined set its default value to CAR. line # 4 makes vech empty, thus default value set to car. This is known as parameter expansion. See bash man page for other fancy usage.
Code:
man bash
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