1#!/usr/bin/perl 2use warnings; 3use strict; 4 5my ($begun, $ended); 6 7while (<>) { 8 chomp; 9 if (not $begun) { 10 s/.*<math class="eqn">// or next; 11 $begun = 1; 12 next unless length; 13 } 14 s/<\/math>.*// and $ended = 1; 15 s/^ *//; 16 print "$_\n" if length; 17 exit 0 if $ended; 18} 19 20die "unexpected end of file"; 21