Perhaps this is why use of regex is so controversial amongst a majority of "professional" programmers. They are trying to use PCRE for every pattern matching task, i.e, even ones where it is not necessary, whether it is within their programing language or with command-line utilities. This "Bash one-liner" is a simple example.

I have reviewed a number of books written about regular expressions and for the most part^1 they focus only on regex as implemented in popular programming languages. That almost invariably is PCRE or some form of PCRE-like pattern matching. There is little distinction, let alone acknowledgment, between PCRE/PCRE-like patterns and anything simpler.

Not being a "professional" programmer, I use regex everyday but I never (intentionally) use PCRE.^2 Too complicated for my tastes, not to mention slow if using backtracking.

1. I recall one older book that did include an incomplete table attempting to show which type of regex was used by various UNIX utilities in addition to what regex was used by popular programming languages of the day.

2. For programs that optionally link to a PCRE library, I re-compile without them without it.