my $sgml = < Hello, world!heading SGML while ($sgml=~s#(<)([^/<>\s]+)((?:\s[^/<>]+)?>)([^<>]+)(<[^/<>]+>)#$1$2$3$4$1\/$2>$5#){} print "\n\n"; print "\nOutput:\n$sgml\n"; print "\n\n";