use Term::ReadKey;

my $prompt = "Gimme a char: ";

while (1) {
  # updated to use the erase-to-EOL escape sequence
  print "\r$prompt\e[K";

  my $key = "";
  my $str = "";

  ReadMode "cbreak";

  do {
    print $key;
    $str .= $key;
    $key = ReadKey;
  } while $key ne "\n";

  ReadMode "normal";
}