Using this Perl module you can walk step-by-step through what a regexp engine actually does given a regexp and a string to match against: https://metacpan.org/

Using this Perl module you can walk step-by-step through what a regexp engine actually does given a regexp and a string to match against: https://metacpan.org/pod/Regexp::Debugger https://metacpan.org/pod/Regexp::Debugger After installing the module it can be started simply by calling `rxrx` on the command line.