if ($toaddress =~ /(\S+)[@]yourdomain|yourotherdomain/) {
   $user = $1;
} else {
   warn "Unknown user:  $toaddress\n";
   $user = 'postmaster'; # Or whoever should get slop.
}


##</code><code>##

# This is untested.
@users = map {
  /^(\S+)[@]/ ? $1 : undef
} grep {
  /(yourdomain|yourotherdomain|yourthirddomain)$/
}  map {
  s/\".*?\"//g;
  (/[<](\S+?)[>]/) ? $1 : undef
} map {
  split /,\s*/, $_
} $headers =~ m/^(?:To|Cc)[:]\s*(.*?)$/mig;
if (not @users) {
  warn "No users.\n";
  @users = ('postmaster');
}


##</code><code>##

  my $filename = "attachment"; {
    my ($y, $m, $d) = (localtime)[5,4,3];
    $y += 1900; $m += 1;
    $filename = join "-", $filename, $y, $m, $d;
  }
  # I assume $user and $ext are already set to the
  # username and the filetype extension respectively.
  while (-e "/home/$user/$filename.$ext") {
    $filename .= ('a'..'z')[rand 26];
    # It is possible to be more elegant than this.
  }
  open FILEHANDLE, ">/home/$user/$filename.$ext";
  binmode FILEHANDLE; # Probably not necessary on *nix.
  print FILEHANDLE $content;
  close FILEHANDLE;


##</code><code>##

$;=sub{$/};@;=map{my($a,$b)=($_,$;);$;=sub{$a.$b->()}}
split//,".rekcah lreP rehtona tsuJ";$\=$ ;->();print$/