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;