specifically, grep --perl-regexp gives me this error
Is there a *BSD equivalent option? (can provide context if necessary)
pfr About a year ago, I've enabled the -P flag on ripgrep, you could use that instead. Base grep on NetBSD does not support this option, as you already found out.
pfr are you sure you can't do it with egrep? Or printf? If not, you use plain perl -nle. See perlrun, and this tutorial
pfr Just use pcregrep. If you have pcre installed (very likely), then you have pcregrep.
rvp Any flags needed or just simply pcregrep?
pfr Should work w/o any flags.