In checking over a project recently, I wanted to extract all PHP code from a set of files and combine it into a single output so I could easily assess what was being used. The eventual command I ended up with was as follows, hopefully it will be useful to someone else in the future:

find -name \*.php | xargs perl -nE 'BEGIN{ undef $/ } say for /<\?php\s*((?:(?!\s*\?>).)+)/sg'