use strict;
my $str = 'https://domain.com/path/to/assets/css/styles.css
https://domain.com/path/to/assets/css/styles.min.css
https://domain.com/path/to/assets/js/main.js
https://domain.com/path/to/assets/js/main.min.js
https://domain.com/path/to/assets/css/styles.1666040041.css
https://domain.com/path/to/assets/css/styles.1666040041.min.css
https://domain.com/path/to/assets/js/main.1666040041.js
https://domain.com/path/to/assets/js/main.1666040041.min.js';
my $regex = qr/^(.+)\.(\d+)\.(min\.)?(css|js)$/mp;
my $subst = '$1.$3$4';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html