python's `if __name__ == "__main__"`, but for php.

README.md

A slightly fuller example for this stackoverflow question: PHP equivalent of Python's name == “main”?

If you run php import.php the expected output is:

$ php import.php 
I am import.php
I am import.php, and I was run from the command line.

If you run php run.php the expected output is:

$ php run.php 
I am run.php
I am import.php
I am run.php, and I was run from the command line.

import.php

<?php
print_r("I am import.php\n");

// If this is the file that was run from the command line.
if (!debug_backtrace()) {
  // do useful stuff
  print_r("I am import.php, and I was run from the command line.\n");
}

run.php

<?php
print_r("I am run.php\n");
require_once('import.php');

if (!debug_backtrace()) {
  // do useful stuff
  print_r("I am run.php, and I was run from the command line.\n");
}