Day 0: Hello, World.
https://www.hackerrank.com/challenges/30-hello-world/problem
<?php
$_fp = fopen("php://stdin", "r");
$inputString = fgets($_fp); // get a line of input from stdin and save it to our variable
// Your first line of output goes here
print("Hello, World.\n");
// Write the second line of output
print($inputString);
fclose($_fp);
?>