CODE EXAMPLE FOR SHELL

php 7 to php 8 in ubuntu 20.04

sudo apt install software-properties-common
sudo add-apt-repository ppa:ondrej/php
sudo apt update
sudo apt install php8.0
 #install common extension 
sudo apt install php8.0-common php8.0-mysql php8.0-xml php8.0-xmlrpc php8.0-curl php8.0-gd php8.0-imagick php8.0-cli php8.0-dev php8.0-imap php8.0-mbstring php8.0-opcache php8.0-soap php8.0-zip php8.0-intl -y
  sudo a2dismod php7.0
  sudo a2dismod php7.1
  sudo a2dismod php7.2
  sudo a2dismod php7.3
  sudo a2dismod php7.4
sudo a2enmod php8.0
sudo service apache2 restart