$ sudo apt-get install python-software-properties
$ sudo add-apt-repository ppa:ondrej/PHP
$ sudo apt-get update
$ sudo apt-get install -y PHP5

参考：
https://askubuntu.com/questions/756181/installing-php-5-6-on-xenial-16-04
https://askubuntu.com/questions/756879/cant-install-php5-on-ubuntu-16-04

参考：
https://github.com/oerdnj/deb.sury.org/issues/56

sudo apt install -y language-pack-en-base
sudo locale-gen en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8