PHPでカレンダー出力 ref: http://qiita.com/elzup/items/66a51dad716536aff159

cal.php

<?php
$col_width = 3;
$title_format = '-*- Y-m -*-';

// 引数がない場合は今月
$ts = strtotime("first day of");
if (isset($argv[2])) {
    $ts = strtotime("first day of {$argv[1]}-{$argv[2]}");
}
list($y, $m, $t, $w) = explode(',', date('Y,m,t,w', $ts));
// title
$title = str_replace(array('Y', 'm'), array($y, sprintf('%2d', $m)), $title_format);
echo str_repeat(' ', ($col_width * 7 - strlen($title)) / 2) . $title . PHP_EOL;
echo str_repeat(' ', $w * $col_width);
for ($i = 1; $i <= $t; $i++) {
    echo sprintf("%{$col_width}d", $i);
    if (($w + $i) % 7 == 0) {
        echo PHP_EOL;
    }
}
echo PHP_EOL;

file1.txt

   -*- 2014-12 -*-
     1  2  3  4  5  6
  7  8  9 10 11 12 13
 14 15 16 17 18 19 20
 21 22 23 24 25 26 27
 28 29 30 31