Creating A Game With PHP Part 1: Detecting Key Input (see https://www.hashbangcode.com/article/creating-game-php-part-1-detecting-key-input)

detectkeys.php

<?php

function translateKeypress($string) {
  switch ($string) {
    case "\033[A":
      return "UP";
    case "\033[B":
      return "DOWN";
    case "\033[C":
      return "RIGHT";
    case "\033[D":
      return "LEFT";
    case "\n":
      return "ENTER";
    case " ":
      return "SPACE";
    case "\010":
    case "\177":
      return "BACKSPACE";
    case "\t":
      return "TAB";
    case "\e":
      return "ESC";
   }
  return $string;
}

$stdin = fopen('php://stdin', 'r');
stream_set_blocking($stdin, 0);

system('stty cbreak -echo');

while (1) {
  $line = fgets($stdin);
  if ($line) {
    echo 'Key pressed: ' . translateKeypress($line) . PHP_EOL;
  }
}