use strict;
my $str = '<html>
<head>
<title>Hello</title>
</head>
<body>
<p>this is a simple text in html file</p>
<a href="https://google.com">Google</a>
<a href="/frontend/login/">Login</a>
<a href="/something/work/">Something</a>
</body>
</html>';
my $regex = qr/href="\//mp;
my $subst = 'href="\\/more\\/';
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