use strict;
my $str = 'Content-Transfer-Encoding: base64
DQoNCg0KDQoNCg0KDQoNCg0KDQpbQiZRXTxodHRwOi8vd3d3LmRpeS5jb20+DQoNCg0KDQoNCg0K W2h0dHA6Ly9raW5nZmlzaGVyLnNjZW5lNy5jb20vaXMvaW1hZ2UvS2luZ2Zpc2hlci9pY29uX3N0 b3JlX2xvY2F0b3I/d2lkPTM2JmhlaT0zNiZxbHQ9MTAwXTxodHRwOi8vd3d3LmRpeS5jb20vZmlu ZC1hLXN0b3JlPg0KDQoNCg0KRmluZCBhIHN0b3JlPGh0dHA6Ly93d3cuZGl5LmNvbS9maW5kLWEt c3RvcmU+DQoNCg0KDQoNCkN1c3RvbWVyIFNlcnZpY2VzDQoNCjAzMzMgMDE0IDMzNTcNCg0KDQoN Cg0KDQoNCg0KDQoNCkluc3BpcmF0aW9uPGh0dHA6Ly93d3cuZGl5LmNvbS9pbnNwaXJhdGlvbi8w Lmlyb290Pg0KDQpQcm9qZWN0czxodHRwOi8vd3d3LmRpeS5jb20vcHJvamVjdHMvMi5wcm9vdD4N Cg0KU2hvcDxodHRwOi8vd3d3LmRpeS5jb20vc2hvcC8+DQoNCkhlbHAgJiBBZHZpY2U8aHR0cDov L3d3dy5kaXkuY29tL2hlbHAtYWR2aWNlLzEuaHJvb3Q+DQoNCk15IGFjY291bnQ8aHR0cDovL3d3 dy5kaXkuY29tL2N1c3RvbWVyL215X2FjY291bnQvPg0KDQoNCg0KDQoNCg0KDQoNCg0KRGVhciBC ZW4gUGF0b24NCg0KDQoNCg0KVGhhbmsgeW91IGZvciB5b3VyIG9yZGVyDQoNCg0KDQoNCg0KT3Jk ZXIgbnVtYmVyOg0KDQowMDYzMTA5MDU1DQoNCg0KDQpUb3RhbCBDb3N0Og0KDQrCozMuMjcNCg0K DQoNClRoYW5rIHlvdSBmb3Igb3JkZXJpbmcgZnJvbSBCJlEuIFlvdeKAmWxsIGZpbmQgZGV0YWls cyBvZiB5b3VyIG9yZGVyIGFuZCBkZWxpdmVyeSBvciBjb2xsZWN0aW9uIGluZm9ybWF0aW9uIGJl bG93LiBGb3IgaGVscCB3aXRoIHF1ZXN0aW9ucyBhYm91dCBvdXIgc2VydmljZSwgcGxlYXNlIHNl';
my $regex = qr/Content-Transfer-Encoding: base64\s+(.*?)$/mip;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
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