Tested on Linux, OpenBSD, & Mac: POSIX: man 7 re_format PCRE: man pcrepattern PCRE2: man pcre2pattern PCRE may be a "works on my machine" thing, but POSIX s

Tested on Linux, OpenBSD, & Mac: POSIX: man 7 re_format PCRE: man pcrepattern PCRE2: man pcre2pattern PCRE may be a "works on my machine" thing, but POSIX should be there.