302-Ubuntu16.04 安装php5.6 和 php7.0

`参考：http://askubuntu.com/questions/761713/how-can-i-downgrade-from-php-7-to-php-5-6-on-ubuntu-16-04

UpdateToday I got again problem with PHP 7 running despite I have disabledphp7.0
apache module:phpinfo
was showing php 7 using fastCGI ...... So if after you follow the below instructions you face this situation, you may need to disable theproxy_fcgi
apache module:

sudo a2dismod proxy_fcgi proxy; sudo service apache2 restart

1. Re-Install PHP 5.6
What worked for me was this guide: http://www.lornajane.net/posts/2016/php-7-0-and-5-6-on-ubuntu
Actually is not required to removephp7.0
, you can install php5.6 together ( also because you will have dependency problem withphpmyadmin
package that required php7.0)
Assuminglibapache2-mod-php
is a suitable way to enable PHP in Apache for you, you can proceed in this way:

sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.0 php5.6 php5.6-mysql php-gettext php5.6-mbstring php-xdebug libapache2-mod-php5.6 libapache2-mod-php7.0

2. Switch PHP version:
From php5.6 to php7.0 :
Apache:

sudo a2dismod php5.6 ;
sudo a2enmod php7.0 ; 
sudo service apache2 restart
sudo ln -sfn /usr/bin/php7.0 /etc/alternatives/php

from php7.0 to php5.6:
Apache:

sudo a2dismod php7.0 ; 
sudo a2enmod php5.6 ;
sudo service apache2 restart
sudo ln -sfn /usr/bin/php5.6 /etc/alternatives/php