topic Re: Regular expression help in Operating System - Linux

Regular expression help

Jeff_Traigle — Mon, 17 Dec 2007 00:48:45 GMT

Ok, this is my weakest part of scripting things and there's probably some short regexp I could use with sed to accomplish what I need so I'll pick people's brains on here. :)

I have an XML configuration file that has a line with the following format:

I'm trying to grab the "cluster" portion of the string. However, the id and ordered parameters can be reversed randomly so it's not as simple as I'd assumed at first.

Re: Regular expression help

Dennis Handly — Mon, 17 Dec 2007 01:10:37 GMT

What do you want to grab? "cluster_pkg"?
You could just ignore the "ordered" part:

$ sed -e 's/group id="$.*$" /\1/' file

This should work as long as "true" doesn't have a space after it.

Re: Regular expression help

Dennis Handly — Mon, 17 Dec 2007 01:16:08 GMT

Oops that doesn't handle the reverse. I assume you are only getting lines with the two?
$ sed -e 's/ -e 's/ group id="$.*$">/\1/' file

Re: Regular expression help

Jeff_Traigle — Mon, 17 Dec 2007 01:35:56 GMT

Close, but not quite there... I modified it a little to get really close to what I need.

testfile contains:

With this command:

sed 's/.*id="$.*_pkg$".*/\1/' testfile

It returns:

cluster_pkg
cluster_pkg

I don't want the _pkg portion of the string either though.

Re: Regular expression help

Jeff_Traigle — Mon, 17 Dec 2007 01:38:34 GMT

Got it! Moved the \) to before the _pkg in the sed command. Yippe! :)

Command looks like this:

sed 's/.*id="$.*$_pkg".*/\1/' testfile

Re: Regular expression help

Dennis Handly — Mon, 17 Dec 2007 01:39:59 GMT

>I don't want the _pkg portion of the string either though.

Ah, that makes it easier.
$ sed 's/.*id="$.*$_pkg".*/\1/' testfile