Using sipP as a Call Generator to load test Asterisk on Ubuntu Server
Handy regex for cdr processing
If you have a sip:+firstname.lastname@example.org number and you need to cut out some digits out of the +15558675309123 once you've parsed it out regex lookaround can be your best friend.
Try using ^(\+.*)(?=...$) in your parser and you will instantly find your needed results of +15558675309 are available.