#!/usr/bin/perl

use warnings;

if (not defined $ENV{MSGFILTER_PREV_MSGID}) {
  while (<>) {
    print $_;
  }
  exit;
}

my $first = 1;
if (("%s: " . $ENV{MSGFILTER_MSGID} . "\n") eq $ENV{MSGFILTER_PREV_MSGID}) {
  while ($l = <>) {
    if ($first) {
      $l =~ s/^%s: (.*)/$1/;
      $first = 0;
    }
    $l =~ s/\n$// if eof(STDIN);
    print $l;
  }
} else {
  while (<>) {
    print $_;
  }
  exit;
}