Apache提供的空白php页面

Question

I recently installed apache, mysql, and php on my machine in an effort to learn some web development. Until yesterday, I had no problems with configuration - everything was working fine.

This is my file structure

/var/www/html/
    info.php
    phptutorial/
        index.php
        core/(more php)
        css/(more php)
        includes/(more php)

Apache is working (status: running) and when I navigate to localhost in Chrome I see the correct directory listing. However when I further navigate into the phptutorial/ directory, I am served a blank page and cannot access index.php. Yesterday the page loaded fine. I think it's a configuration problem with apache or php. The file permissions on my directories are all 755.

Any ideas? I also noticed that strangely there is no httpd.conf located in /etc/apache2/. The userdir module is enabled.

uname -a; php -v; apache2 -v

Linux portege-R935 3.13.0-53-generic #89-Ubuntu SMP Wed May 20 10:34:39 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
PHP 5.5.9-1ubuntu4.9 (cli) (built: Apr 17 2015 11:44:57) 
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies
    with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies
Server version: Apache/2.4.7 (Ubuntu)
Server built:   Mar 10 2015 13:05:59

Answer 1

Ok I realized my problem. In one of my php files I was using require() to require a file which I had not yet created. Mittmemo was right, the problem was the php and not the server configuration. Should you find yourself with a blank page then thoroughly check the php code for such mistakes.