Ubuntu Bash Scripting for PHP Version Switching

To create a bash script for switching between different versions of PHP on Ubuntu, you can follow these steps:

1. First, you need to have multiple versions of PHP installed on your system. You can use packages like php7.x, php8.x from Ubuntu repositories or other sources like ppa:ondrej/php for newer versions.
2. Create a bash script that will switch between these versions based on user input.

Here's a simple example of such a script:

#!/bin/bash
# Function to switch PHP version
switch_php_version() {
    from_version=$1
    to_version=$2
    # Disable current PHP version
    sudo a2dismod "php${from_version}"
    
    # Enable the new PHP version
    sudo a2enmod "php${to_version}"
    # Set the new PHP version as the default
    sudo update-alternatives --set php "/usr/bin/php${to_version}"
    # Restart Apache
    sudo service apache2 restart
    echo "PHP version switched from ${from_version} to ${to_version}"
}
# Main menu
echo "Available PHP versions:"
echo "1. PHP 7.4"
echo "2. PHP 8.1"
echo "Enter the number of the version you want to switch to: "
read choice
case $choice in
    1) switch_php_version 8.1 7.4 ;;
    2) switch_php_version 7.4 8.1 ;;
    *) echo "Invalid choice. Exiting." && exit 1 ;;
esac

Save this script in a file, for example, php_switcher.sh, make it executable using chmod +x php_switcher.sh, and then you can run it using ./php_switcher.sh. It will prompt you to select a PHP version, and upon selection, it will switch to that version and restart Apache.

Please note that this is a basic script and may need adjustments based on your specific PHP setup and requirements. Additionally, you might need to modify Apache configuration paths or commands if you're using a different web server like Nginx. 

This Bash script provides a convenient way to switch between different versions of PHP on an Ubuntu system running Apache web server. It presents a simple menu where the user can choose the PHP version they want to switch to.

The switch_php_version function takes two arguments: the current PHP version and the version to switch to. It disables the current PHP module, enables the new PHP module, updates the system's default PHP version, and restarts Apache to apply the changes. After completing the switch, it notifies the user of the successful version change.

The main menu displays the available PHP versions, currently supporting PHP 8.1 and PHP 7.4. The user is prompted to enter the number corresponding to the desired PHP version. Based on the user's choice, the script calls switch_php_version with the appropriate PHP versions, or exits if an invalid choice is entered.