The best and simplest way to get input from a user in the CLI with only PHP is to use fgetc() function with the STDIN constant:
<?php
echo 'Are you sure you want to quit? (y/n) ';
$input = fgetc(STDIN);
if ($input == 'y')
{
    exit(0);
}
?>(PHP 4, PHP 5, PHP 7, PHP 8)
fgetc — Lee un carácter en un fichero
streamEl puntero de archivo debe ser válido y apuntar a un archivo abierto con éxito por fopen() o fsockopen() (y no cerrado aún por fclose()).
   Devuelve una cadena que contiene un solo carácter, leído desde el fichero apuntado por
   stream. Devuelve false al final del fichero.
  
 Esta función puede retornar false, pero también puede retornar un valor equivalente a false.
 Por favor, lea la sección sobre los booleanos para más información.
 Utilice el operador ===
 para probar el valor de retorno exacto de esta función.
Ejemplo #1 Ejemplo con fgetc()
<?php
$fp = fopen('somefile.txt', 'r');
if (!$fp) {
    echo 'No es posible abrir el fichero somefile.txt';
}
while (false !== ($char = fgetc($fp))) {
    echo "$char\n";
}
?>Nota: Esta función maneja strings binarios.
The best and simplest way to get input from a user in the CLI with only PHP is to use fgetc() function with the STDIN constant:
<?php
echo 'Are you sure you want to quit? (y/n) ';
$input = fgetc(STDIN);
if ($input == 'y')
{
    exit(0);
}
?>You can't just simple print separated characters of a text which is encoded in multibyte character set like this;
Because fgetc() will break each multibyte character on its every byte. Consider this example: 
<?php
$path = 'foo/cyrillic.txt';
$handle = fopen($path, 'rb');
while (FALSE !== ($ch = fgetc($handle))) {
    $curs = ftell($hanlde);
    print "[$curs:] $ch\n";
}
/* The result will be something like this:
<
[1]: <
[2]: h
[3]: 2
[4]: >
[5]: �
[6]: �
[7]: �
[8]: �
[9]: �
[10]: �
[11]:  
[12]: �
[13]: �
[14]: �
[15]: �
[16]: �
*/ ?>
I don't think this is the best, but it can be a workaround:
<?php
$path = 'path/to/your/file.ext';
if (!$handle = fopen($path, 'rb')) {
    echo "Can't open ($path) file';
    exit;
}
$mbch = '';    // keeps the first byte of 2-byte cyrillic letters
while (FALSE !== ($ch = fgetc($handle))) {        
    //check for the sign of 2-byte cyrillic letters    
    if (empty($mbch) && (FALSE !== array_search(ord($ch), Array(208,209,129)))) {
        $mbch = $ch;    // keep the first byte
        continue;
    }
    $curs = ftell($handle);
    print "[$curs]: " . $mbch . $ch . PHP_EOL;
    // or print "[$curs]: $mbch$ch\n";
    if (!empty($mbch)) $mbch = '';    // erase the byte after using
}
?>I was using command-line PHP to create an interactive script and wanted the user to enter just one character of input - in response a Yes/No question.  Had some trouble finding a way to do so using fgets(), fgetc(), various suggestions using readline(), popen(), etc.  Came up with the following that works quite nicely:
$ans = strtolower( trim( `bash -c "read -n 1 -t 10 ANS ; echo \\\$ANS"` ) );To read a single key-press in CLI mode, you can either use ncurses (which will probably require additional modules for PHP) or get nasty with the *nix "/bin/stty" command)
<?php
   function stty($options) {
      exec($cmd = "/bin/stty $options", $output, $el);
      $el AND die("exec($cmd) failed");
      return implode(" ", $output);
   }
   function getchar($echo = false) {
      $echo = $echo ? "" : "-echo";
      # Get original settings
      $stty_settings = preg_replace("#.*; ?#s", "", stty("--all"));
      # Set new ones
      stty("cbreak $echo");
      # Get characters until a PERIOD is typed,  
      # showing their hexidecimal ordinal values.
      printf("> ");
      do {
         printf("%02x ", ord($c = fgetc(STDIN)));
      } while ($c != '.');
      # Return settings
      stty($stty_settings);
   }
   getchar();
?>