Introduction
PHP is an open source general-purpose scripting language that is widely used and best suited for developing websites and web applications. It is a server-side scripting language that can be embedded into HTML.
Currently, there are three supported versions of PHP i.e Versions 7.0, 7.2, 7.8, 8.0 and 8.1. As a modern-day web developer who works on different frameworks, packages need to have the multiple versions of PHP installed on your VPS.
During your development, not all your projects may support the latest version (V. 8.1) resulting you to downgrade to a much earlier version. In this tutorial, we will illustrate how to switch between the different versions of PHP from 8.1 to 7.2 to enable you to run your projects smoothly.
Prerequisites
- Ubuntu 22.04 operating system
- Web server (in this demo, we use Apache web server, you can learn how to install on our tutorial – How To Install Apache, MariaDB, and PHP (LAMP stack) in Ubuntu.
- A non-root user with sudo privileges.
- Have 2 different versions of PHP installed on your VPS
Steps
Upgrade your system packages
$ sudo apt upgrade
$ sudo apt install software-properties-common apt-transport-https –y
$ sudo add-apt-repository ppa:ondrej/php –y
Update the system repositories:
$ sudo apt update
$ sudo apt install php8.1 libapache2-mod-php8.1
$ sudo apt install php7.2
Run the command to check the set default version of PHP
$ php –v
By default, Ubuntu will set the latest, stable version of PHP as the default i.e. version 8.1.To switch to the alternative version (7.2)
$ sudo a2dismod php8.1 $ sudo a2enmod php7.2 $ sudo service apache2 restart $ sudo update-alternatives --set php /usr/bin/php7.2
You can also use the following command to switch from one Php version to another installed php version:
$ sudo update-alternatives --config php
Enter the choice ‘number’ that you want to set as default php version.
$ php --version
$ sudo systemctl restart nginx
You can now check the current version of PHP again:
$ php -v
You will notice the version has changed from version 8.1 to 7.2. Of course, the opposite can be done by following the steps above and replacing the version of PHP in each step and voila! You are back to your previous version.
This process may seem repetitive and tedious, so to make it easy, you can encapsulate the entire process in a function. For example, we want to switch between 7.2 to 7.0 php version.
To do this, open your .bashrc file with your favorite editor, in this case, we use nano.
$ sudo nano ~/.bashrc
Scroll to the last line and type in the following code:
changephpversion () {
local IS_PHP7=`php -version|grep "PHP 7.2"`
if [[ -z $IS_PHP7 ]] ; then
echo "Switching... Please wait"
sudo a2dismod php7.0;
sudo a2enmod php7.2;
sudo service apache2 restart
sudo update-alternatives --set php /usr/bin/php7.2
else
echo "Switching... Please wait"
sudo a2dismod php7.2;
sudo a2enmod php7.0;
sudo service apache2 restart
sudo update-alternatives --set php /usr/bin/php7.0
fi
}
Exit your editor while saving changes and incorporate the new changes by typing below command:
$ source ~/.bashrc
Now when you type ‘changephpversion’ on your terminal, the function will automatically switch to the alternative version.
Conclusion
You can try out this tutorial with different PHP versions. Very simple indeed! Your query to the best web hosting can end by clicking on this link.
