[TriLUG] bash scripting and regex help

[Mitchell Amiano]

Or use variable substring removal:

f=${filename#version_}
CMD=${f%.jar}

Two steps, but they are both built-ins, and avoids the quotes as well as the process that expr will fork. 

On Apr 25, 2012, at 10:52 AM, Chris Merrill wrote:

> 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
> 
> 
> -- 
> ------------------------------------------------------------------------ -
> Chris Merrill                           |  Web Performance, Inc.
> chris at webperformance.com                |  http://webperformance.com
> 919-433-1762                            |  919-845-7601
> 
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Mitchell Amiano
(919) 410-8008
mamiano at nc.rr.com