need help with awk

[Guillaume CHARDIN <guillaume.chardin@gmail.com>]

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 ?

Thanks for you help.

-- 
Guillaume