Read a single character of input from the TTY without waiting for the enter in PHP CLI

fread.php

#!/usr/bin/env php
<?php
// 保存当前 tty 设置
$term = shell_exec("stty -g");

// 关闭 tty 规范输入模式
// link http://www.faqs.org/docs/Linux-HOWTO/Serial-Programming-HOWTO.html#AEN92
system("stty -icanon");

while ($c = fread(STDIN, 1)) {
    printf("%c\n", $c);
}

// 重置 tty 设置
system(sprintf("stty %s", $term));

readline.php

#!/usr/bin/env php
<?php
readline_callback_handler_install('', function () {});
while (true) {
  $read = array(STDIN);
  $write = $except = null;
  $number = stream_select($read, $write, $except, 0, 100000);
  if ($number && in_array(STDIN, $read)) {
    $char = stream_get_contents(STDIN, 1);
    echo "Char read: $char\n";             
  }
}