grep -E on older distros

[cepal]

on older distros "grep -E" doesn't work as the script intends. the solution - which also works in NEW distros, is to use "grep -P" instead; I've tested it on RHEL5/6/7 - where as with "grep -E" it wouldn't have worked on RHEL5.

[cepal]

I've created a forked update to the "ptrap" script and created a "pull request". Hope it gets merged into the master version soon ;-)