To install different versions of php on your linux/ubuntu machine follow the commands below:
# first check to see if we have php installed sudo apt show php //OR sudo apt show php -a // to install default php version // from ubuntu software repository sudo apt install php // Install PHP (5.6, 7.x, 8.0) on Ubuntu Using PPA sudo apt install python-software-properties sudo add-apt-repository ppa:ondrej/php sudo apt-get update // for apache server // choose only the version you need // from the following list sudo apt install php5.6 sudo apt install php7.0 sudo apt install php7.1 sudo apt install php7.2 sudo apt install php7.3 sudo apt install php7.4 sudo apt install php8.0 // for nginx server // choose only the version you need // from the following list sudo apt install php5.6-fpm sudo apt install php7.0-fpm sudo apt install php7.1-fpm sudo apt install php7.2-fpm sudo apt install php7.3-fpm sudo apt install php7.4-fpm sudo apt install php8.0-fpm // if you want to install php extentions // use following command after you ran above commands // choose one of the following as per your php requirements sudo apt install php5.6-cli php5.6-xml php5.6-mysql sudo apt install php7.0-cli php7.0-xml php7.0-mysql sudo apt install php7.1-cli php7.1-xml php7.1-mysql sudo apt install php7.2-cli php7.2-xml php7.2-mysql sudo apt install php7.3-cli php7.3-xml php7.3-mysql sudo apt install php7.4-cli php7.4-xml php7.4-mysql sudo apt install php8.0-cli php8.0-xml php8.0-mysql // check installed php version php -v // how to switch to different version sudo update-alternatives --set php /usr/bin/php5.6 sudo update-alternatives --set php /usr/bin/php7.0 sudo update-alternatives --set php /usr/bin/php7.1 sudo update-alternatives --set php /usr/bin/php8.0