How do the environments of a standard Terminal command-line and a bash script differ?

Posted by fred.bear on Ask Ubuntu See other posts from Ask Ubuntu or by fred.bear
Published on 2011-01-10T08:41:07Z Indexed on 2011/01/10 8:58 UTC
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Filed under:

bash

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shell

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shell-scripting

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environment

I know there is something different about the environment of the Terminal command-line and the environment in a bash script, but I don't know what that difference is...

Here is the example which finally led me to ask this quesiton; it may flush out some of the differences.

I am trying to strip leading '0's from a number, with this command.

var="000123"; var="${var##+(0)}" ; echo $var

When I run this command from the Terminal's command-line, I get: 123

However, when I run it from within a script, it doesn't work; I get: 000123

I'm using Ubuntu 10.04, and tried all the following with the sam results:

GNOME Terminal 2.30.2
Konsole 2.4.5
#!/bin/bash
#!/bin/sh

What is causing this difference?

Even if some upgrade will make it work in scripts...
I am trying to find out the what and why, so in future, I'll know what to look out for .

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