Hi again

I skimmed thru https://www.postgresql.org/docs/14/functions-matching.html and found some features which were new to me.

E.g. I've never heard of metacharacters \m or \M (?) I tested them and Perl will only see the escaped characters, i.e. literal m and M .

> It would be ideal if Perl 5.6 were a superset of Posix.

I'm afraid Postgres has another incompatible superset of Posix

Further searching revealed that PG is apparently using the TCL RE-engine and

> There are a number of important differences between Tcl Advanced Regular Expressions and Perl-style regular expressions. Tcl uses \m, \M, \y and \Y for word boundaries. Perl and most other modern regex flavors use \b and \B. In Tcl, these last two match a backspace and a backslash, respectively.

see here for more:

• https://www.regular-expressions.info/tcl.html
• https://www.regular-expressions.info/postgresql.html

good luck with that using Perl tools. :|

I think you will be better off using something from the TCL toolchain.