with linux bash shell , how can i use regex to get a certain string of a file

by example:

for filename *.tgz
do 

"get the certain string of filename (in my case, get 2010.04.12 of file 2010.01.12myfile.tgz)"

done  

or should I turn to perl

Merci

frank


Question: How can I look up which server an application is running on?
Answer: The URL will often indicate where an application is running, e.g. "http://app01.somecompany.com/my/app" is running on "app01", but if your servers are load-balanced that may not be the case.

In cases where the URL isn't revealing you may get lucky and have your system designed in such a way that it discloses which server an application is running on (HTTP headers, &lt;META&gt; tags in the output, a status message sent to a client, etc.), otherwie you're pretty much down to asking around and compiling documentation as to which servers do what.