The following PHP extensions are required but are not installed on my system: gd, pdo_mysql, and mbstring. How can I install these extensions on my Ubuntu server using the command line?

The following PHP extensions are required but are not installed on my system: gd, pdo_mysql, and mbstring. How can I install these extensions on my Ubuntu server using the command line?

To install the required PHP extensions (gd, pdo_mysql, and mbstring) on your Ubuntu server using the command line, follow the steps below:

1. Update the package index:

Before installing the PHP extensions, it's a good practice to update the package index to ensure you have the latest packages available. Run the following command:

sudo apt update

2. Install PHP development tools:

To install the required PHP extensions, you need to have the PHP development tools installed. Run the following command to install them:

sudo apt install php-dev libapache2-dev libmysqlclient-dev libxml2-dev zlib1g-dev

3. Install gd extension:

To install the gd extension, you need to install the imagick package, which is a replacement for the gd library. Run the following command:

sudo apt install imagemagick php-imagick

After the installation is complete, you need to enable the extension in PHP. Edit the php.ini file using the following command:

sudo nano /etc/php/7.x/apache2/php.ini

Replace "7.x" with your PHP version number if it's different. Find the following line and uncomment it by removing the semicolon at the beginning:

extension=gd.so

Save and close the file. Restart Apache to apply the changes:

sudo systemctl restart apache2

4. Install pdo_mysql extension:

To install the pdo_mysql extension, run the following command:

sudo apt install php-mysql

After the installation is complete, you need to enable the extension in PHP. Edit the php.ini file using the following command:

sudo nano /etc/php/7.x/apache2/php.ini

Find the following line and uncomment it by removing the semicolon at the beginning:

extension=pdo_mysql.so

Save and close the file. Restart Apache to apply the changes:

sudo systemctl restart apache2

5. Install mbstring extension:

To install the mbstring extension, run the following command:

sudo apt install php-mbstring

After the installation is complete, you need to enable the extension in PHP. Edit the php.ini file using the following command:

sudo nano /etc/php/7.x/apache2/php.ini

Find the following line and uncomment it by removing the semicolon at the beginning:

extension=mbstring.so

Save and close the file. Restart Apache to apply the changes:

sudo systemctl restart apache2

After following the above steps, the required PHP extensions (gd, pdo_mysql, and mbstring) should be installed and enabled on your Ubuntu server. You can verify the installation by running the following PHP script in a new file called "phpinfo.php":

<?php
phpinfo();
?>

Save the file and place it in the web root directory (/var/www/html/). Access the file in your web browser (e.g., http://yourserver.com/phpinfo.php), and look for the sections "gd", "PDO", and "mbstring" to confirm that the extensions are installed and enabled.