[TriLUG] bash scripting and regex help

[Chris Merrill]

I'm trying to script a process and part of it needs to extract a version
number from a filename.  I can do this from the command line easily enough...
here is a simplified example:

> [root at dawn scripts]# expr match "version_5.1.10577.jar" 'version_\(.*\)\.jar'
> 5.1.10577

The output is exactly what I need. But when I try to do the same thing inside
a script, I get nothing.  This is the script:

#!/bin/bash
#
filename=version_5.1.10577.jar
expression="version_\(.*\)\.jar"
CMD="expr match \"$filename\" '${expression}'"
echo $CMD
$CMD

and this is the output:

> [root at dawn scripts]# ./test.sh
> expr match "version_5.1.10577.jar" 'version_\(.*\)\.jar'
>
> [root at dawn scripts]#


I've tried a lot of variations, but none of them get me anything that resembles
success, so I think I must be missing something fundamental. Can anyone point
me in the right direction?

TIA!
Chris


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Chris Merrill                           |  Web Performance, Inc.
chris at webperformance.com                |  http://webperformance.com
919-433-1762                            |  919-845-7601

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