PHPで標準入力 ref: http://qiita.com/kiimiiis/items/89ac68e5f7451bf64d1a

file1.txt

C:\xampp\htdocs\PhpProject1>php ./single.php
1
string(1) "1"

file3.txt

C:\xampp\htdocs\PhpProject1>php ./multi.php
1
2
3
テスト
5

array(5) {
  [0]=>
  string(1) "1"
  [1]=>
  string(1) "2"
  [2]=>
  string(1) "3"
  [3]=>
  string(6) "テスト"
  [4]=>
  string(1) "5"
}

multi.php

<?php  
$stdins = array();
    while(true)
    {
        $stdin = trim(fgets(STDIN));
        if ($stdin === '')
        {
            var_dump($stdins);
            return;
        }  
        $stdins[] = $stdin;
    }
?>

single.php

<?php  
$stdin = trim(fgets(STDIN));  
var_dump($stdin);
?>