Re: need help with awk

[Kumar Appaiah <a.kumar@alumni.iitm.ac.in>]

On Tue, Oct 06, 2009 at 04:41:43PM +0200, Guillaume CHARDIN wrote:
> Hi,
> 
> In a backup process of some xen virtual machine, i need to extract in
> the config file some informations (in fact the disk line) .
> The line look like this :
>              disk = [ file:/path/to/file,sda1,w ]
> my goal is to isolate le `file` part to use it later. I'm a beginner
> with sed/grep and i dont know it its possible to just extract the part
> between two given regexp. With awk its possible to extract LINES from
> a file with this syntax `awk "/firstFoundRegexp/,/secondRegexp/"`
> this kind of behavior can be applied on one file ?

To extract the file name:
echo disk = [ file:/path/to/file,sda1,w ]|awk 'BEGIN { FS = "[/,]"; } { print $4}'

As for processing only between some lines, you can try this:

<code>
BEGIN { proces_line = 0; }

/startprocessing_regexp/ { process_line = 1 }

process_line {
	     /* Do stuff */
}

/stopprocessing_regexp/ { process_line = 1; }
</code>

Far from elegant, but will work (I think).

HTH.

Kumar