what is the process number of a "running application" ?

[Andrew R Paterson]

On Monday 12 January 2015 19:25:45 Angelo Moreschini wrote:
> Hi,
> 
> I would like to know the process number of an application that actually is
> running (Netbeans in my case), with the purpose to kill it (when is froze).
> 
> But am am not able to know this process number..
> 
> - In the window of gnome-system-monitor the name "netbeans" isn't.
> - The command line : "ps aux | grep netbeans",  give me a full page of
> references..
> 
> Could I know a simple way to have this information ?
> 
> Thank you
> Regards
> 
> Angelo
xprop _NET_WM_PID
and select the relevent window.