use strict; use warnings; my $add  = 0; my $text = do { local $/, }; for my $line (split /\n/, $text) {   print $line;   if ($line =~ m@<\s*/\s*t[dh]@) {      $add = 0;   } elsif ($line =~ m@<\s*t[dh]@) {      $add = 1;   }   print $add ? '
' : "\n"; } __END__   test                                
header1header2 foo bar foobar
column1 foo bar foobar column2