在Ubuntu服务器设置过程中，我需要启用php作为apache2模块。 我尝试运行
如果sudo a2enmod php5返回"$ This module does not exist!"，则应该清除（而不仅仅是删除）libapache2-mod-php5软件包并重新安装它。确保在重新测试网站之前清除浏览器缓存。 然而，运行
我尝试通过升级更新来更新
sudo a2enmod php5，但它返回了ERROR: Module php5 does not exist!
经过一番搜索，我偶然发现了gerard所提供的提示：如果sudo a2enmod php5返回"$ This module does not exist!"，则应该清除（而不仅仅是删除）libapache2-mod-php5软件包并重新安装它。确保在重新测试网站之前清除浏览器缓存。 然而，运行
sudo apt-get --purge remove libapache2-mod-php5后，却返回Package libapache2-mod-php5 is not installed, so not removed。自然地，我尝试使用sudo apt-get install libapache2-mod-php5进行安装，但随即收到以下信息： Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies.
libapache2-mod-php5 : Depends: libxml2 (>= 2.8.0) but 2.7.8.dfsg-5.1ubuntu4.6 is to be installed
Recommends: php5-cli but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
我尝试通过升级更新来更新
libxml2，但没有成功。我还尝试安装 php5-cli，但遇到了以下问题： The following packages have unmet dependencies.
php5-cli : Depends: libxml2 (>= 2.8.0) but 2.7.8.dfsg-5.1ubuntu4.6 is to be installed
Depends: libedit2 (>= 2.11-20080614-4) but 2.11-20080614-3ubuntu2 is to be installed
E: Unable to correct problems, you have held broken packages.
目前我有些迷失。运行php -v命令，显示PHP正在运行，但是：
PHP 5.4.17 (cli) (built: Aug 7 2013 11:40:38)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies