Location regular expression explanation

[Ruslan Ermilov]

On Fri, Aug 03, 2012 at 02:28:09AM -0400, diego_xa wrote:
> Hi,
> 
> I was recently reading the PHPfastcgi example at
> http://wiki.nginx.org/PHPFcgiExample. When it talks about the
> configuration to avoid the exploit on uploads folder, there is a
> regulare expresion saying: location ~*
> (^(?!(?:(?!(php|inc)).)*/blogs\.dir/).*?(php|inc)) {
> 
> I don't understand that regular expresion. Could someone explain me what
> ?! ?: mean or send me some link to documentation about this?? I cannot
> find anything after some googling.
> 
> Thanks and regards.

http://www.pcre.org/pcre.txt