Simple PHP script that can be run from the command line. It illustrates input/output/error usage.

standard-in-out-error.php

<?php

/**
 *  If you call this with "$ php standard-in-out-error.php", 
 *  it will print output and error messages to the command line. 
 *
 *  To pipe just the error messages into their own file,
 *  use "$ php standard-in-out-error.php 2> error.log" 
 */

// This prints 'Please enter your name' on the command line.
fwrite(STDOUT, "Please enter your name:\n");

// This captures what gets typed in and assigns it to $name.
// Note that STDIN includes the carriage return EOL character.
// Here I get rid of it with trim().
$name =	trim(fgets(STDIN));

// Print to the command line again.
fwrite(STDOUT, "Hello $name \n");

// Write this to the standard error pipe.
fwrite(STDERR, "Uh oh! $name was here! \n");

// Exit with a status of 'OK'
exit(0);

?>