while(<IN>)
{
  next if 1../The mail system/; # The condition will be true from line 1 until "The mail system"
  # Code here
}


##</code><code>##

use v5.14;
use Data::Dumper;
my @list = 1..3;

for (@list)
{
  print while (<DATA>);
}

say Dumper \@list;
__DATA__


##</code><code>##

$VAR1 = [
          undef,
          undef,
          undef
        ];