Awk to match string

[SI_TW]

I can't figure out how to pull part of a string that I need using awk.

I have a string that looks like this:

temp=$"buildroot_tag: buildroot_dev_sdev_v2b0064_20111222_dcm"

Using a regex simulator I found I can use:

v[0-9][a-fA-F][0-9]*_[0-9]*[^_.*]

to extract the value I want: v2b0064_20111222

I can't assume too much about the string other than it will be something like *_v*b*_SomeDate_*

I've been able to get to the point of extracting just this line from a document but can't figure out how to get just the part of this string I need.

I thought it should be:

temp=$(echo $temp | awk /v[0-9][a-fA-F][0-9]*_[0-9]*[^_.*]/)

but that just spits out the same thing I started with. I want temp to be equal to:
v2b0064_20111222

How can I do this?

This works but I don't think I can assume it will always work because the number of fields can vary.

echo $temp | awk -F_ '{print $5 "_" $6}'

[atreyu]

you could pipe it to sed, and let it do the stripping/substituting:

#!/bin/bash
temp=$"buildroot_tag: buildroot_dev_sdev_v2b0064_20111222_dcm"
echo $temp |\
 awk /v[0-9][a-fA-F][0-9]*_[0-9]*[^_.*]/ |\
 sed -e 's|^.*\(v[0-9]b[0-9].*_[0-9]*\)_dcm$|\1|'

[SI_TW]

That works great. Thanks