PHP Command Line Confirmation Prompt

prompt.php

$message   =  "Are you sure you want to do this [y/N]";
print $message;
flush();
ob_flush();
$confirmation  =  trim( fgets( STDIN ) );
if ( $confirmation !== 'y' ) {
   // The user did not say 'y'.
   exit (0);
}

Use exit(1) instead of exit(0) to prevent next process running.
Example command: php confirm-this.php && php run-that.php.
If enter n then run-that.php will not run because exit(1).

Also prevent no buffer to flush error with ob_get_level(). Example:

if (ob_get_level() > 0) {
    ob_flush();
}