Can egrep do lookaheads or behinds? I find it necessary to use positive lookaheads to verify the test words include all the letters marked present but in the wrong location.
I was also curious about this as I use grep -P (for PCRE regexes) if I need to use them. Looking at the manual, lookaheads and lookbehinds don't seem to be supported by regular gnu grep or grep -E, so you do need to use grep -P for them.
https://www.gnu.org/software/grep/manual/grep.pdf