[ILUG] Regular Expressions

[Robert Sweetnam]

Hi,

I'm using Squid on Ubuntu 7.10 (just to drag this vaguely on topic!) as 
a reverse proxy. All works very well and I can use Squid to block 
certain useragents instead of using htaccess on each site. However this 
is done using regex and is a feature that is supported by Squid. The 
only thing is when it comes to regular expressions I tend to blank out.

I have basic examples in place that will block the useragent based on 
its identifier. For example to block larbin I use ^larbin or for LibWWW 
perl I use ^LibWWW.

However I would like to make things more specific like blocking 
purported version numbers or any of a number of criteria made up from 
the useragent but my regex ability is dismally weak. For instance how 
would I set about blocking a useragent that contains say Opera, MSIE 6.0 
and ru in the string? This is an example that just recently attempted to 
spam my site:

Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; ru) Opera 8.50

Any suggestions would be greatly appreciated.

Cheers
Robert