Linux Tutorial · Ubuntu 26.04 LTS · PHP 8.5 · Beginner to Intermediate

PHP is a widely used server-side scripting language for websites, content management systems, APIs, and web applications. Ubuntu 26.04 LTS provides PHP packages through its official repositories, making it possible to install PHP without compiling it from source or adding an external repository.

In this tutorial, you will install PHP, verify the command-line interpreter, add common extensions, and configure PHP to work with either Apache or Nginx. You will also learn how to test PHP execution, check service status, and apply basic security practices.

Prerequisites

Before starting, make sure you have the following:

• A computer or virtual machine running Ubuntu 26.04 LTS.
• A user account with sudo privileges.
• Internet access to download packages.
• Apache or Nginx if you want to serve PHP through a web server.
• Basic familiarity with Linux commands and terminal usage.

You can install PHP’s command-line tools without a web server. To execute PHP pages through a browser, however, you need a correctly configured web server and PHP handler.

Step 1: Update Ubuntu Packages

sudo apt update
sudo apt upgrade

Step 2: Install PHP on Ubuntu 26.04

sudo apt install php

php -v

apt policy php

Step 3: Install Common PHP Extensions

PHP extensions add features such as database connectivity, image handling, XML processing, multibyte string support, and HTTP requests. Install only the extensions your application needs.

sudo apt install php-cli php-common php-curl php-mbstring php-xml php-zip php-gd php-intl php-mysql

Check the extensions currently loaded by the PHP command-line interpreter:

php -m

Applications such as WordPress, Laravel, and other frameworks may require additional extensions or specific PHP versions. Consult the application’s current requirements before deploying it.

Step 4: Choose Your Web Server Setup

Choose one of the following approaches for a basic installation. Apache can run PHP through its PHP module or through PHP-FPM. Nginx normally passes PHP requests to PHP-FPM.

Option A: Configure PHP with Apache

sudo apt install apache2 libapache2-mod-php

sudo systemctl enable --now apache2
sudo systemctl restart apache2
sudo systemctl status apache2 --no-pager

sudo apache2ctl configtest

Option B: Configure PHP with Nginx and PHP-FPM

sudo apt install nginx php-fpm

php -v
systemctl list-unit-files 'php*-fpm.service'

sudo systemctl enable --now nginx
sudo systemctl enable --now php8.5-fpm
sudo systemctl status nginx --no-pager
sudo systemctl status php8.5-fpm --no-pager

sudo nano /etc/nginx/sites-available/default

root /var/www/html;
index index.php index.html index.htm;

location ~ \.php$ {
    include snippets/fastcgi-php.conf;
    fastcgi_pass unix:/run/php/php8.5-fpm.sock;
}

ls -l /run/php/

sudo nginx -t
sudo systemctl reload nginx
sudo systemctl status php8.5-fpm --no-pager

Step 5: Create a PHP Test Page

Create a small PHP file to verify that the web server executes PHP instead of returning the source code as plain text.

sudo nano /var/www/html/info.php

Add the following content and save the file:

<?php
echo "PHP is working on Ubuntu!";
?>

Open the following address in a browser running on a machine that can reach the server:

http://SERVER-IP/info.php

Replace SERVER-IP with the server’s actual IP address. If you are testing locally on the server, you can use http://127.0.0.1/info.php.

You should see the message PHP is working on Ubuntu!. If the browser displays the PHP source code, stop and correct the PHP handler configuration before serving other PHP applications.

sudo rm /var/www/html/info.php

Step 6: Check and Configure PHP Settings

PHP uses a php.ini configuration file. The CLI, Apache module, and PHP-FPM may load different configuration files, so changing one file does not necessarily change every PHP execution environment.

Check the active CLI configuration

php --ini
php -i | grep -E 'Loaded Configuration File|memory_limit|upload_max_filesize|post_max_size|date.timezone'

To locate the main configuration files installed on the system, inspect the PHP configuration directory:

ls -la /etc/php/

Common paths include:

Edit the configuration appropriate to your web server. For Nginx with FPM, for example:

sudo nano /etc/php/8.5/fpm/php.ini

For a web application that accepts uploads, you may need to adjust settings such as upload_max_filesize, post_max_size, and memory_limit to values that match the application’s requirements and available server resources. Avoid increasing limits unnecessarily.

After changing the FPM configuration, restart FPM:

sudo systemctl restart php8.5-fpm

For Apache’s PHP module, restart Apache after editing its PHP configuration:

sudo systemctl restart apache2

Step 7: Verify PHP Extensions and Services

Confirm that PHP can load the extensions required by your application:

php -m
php --ri curl
php --ri mysqli

The last command will only return useful module information if the corresponding MySQLi extension is installed and enabled. For FPM-based sites, remember that the CLI and FPM environments can differ.

Check the service status for the web server you selected:

sudo systemctl status apache2 --no-pager

Or, for Nginx with PHP-FPM:

sudo systemctl status nginx --no-pager
sudo systemctl status php8.5-fpm --no-pager

Step 8: Basic PHP Security Best Practices

• Keep PHP updated: regularly install Ubuntu security updates and maintenance releases.
• Remove diagnostic files: delete public test scripts immediately after testing.
• Keep secrets private: do not store database passwords, API tokens, or private keys in publicly accessible directories.
• Use HTTPS: protect website traffic with a valid TLS certificate.
• Install required extensions only: reduce unnecessary components and maintenance overhead.
• Protect FPM: never expose an FPM FastCGI listener to an untrusted network. Use an appropriately restricted Unix socket or protected network configuration.
• Review file permissions: give the web server only the access required by the application.
• Hide production errors: avoid displaying detailed PHP errors to website visitors; log them securely instead.

For production deployments, review the official PHP security documentation and your web application’s security guidance.

Troubleshooting Common PHP Problems

PHP command not found

Check whether PHP is installed and whether APT can find the package:

sudo apt update
sudo apt install php-cli
command -v php
php -v

PHP code appears as text in the browser

The web server may not be configured to execute PHP. Confirm the Apache PHP module or Nginx PHP-FPM configuration, validate the web-server configuration, and restart or reload the relevant service. Do not leave the site publicly accessible until PHP is being handled correctly.

502 Bad Gateway with Nginx

Check that PHP-FPM is running and that the socket path in the Nginx configuration matches the socket created by FPM.

systemctl list-unit-files 'php*-fpm.service'
ls -l /run/php/
sudo nginx -t
sudo journalctl -u php8.5-fpm -n 50 --no-pager

If the FPM unit is not named php8.5-fpm, substitute the actual service name in the journal command.

Apache fails to restart

Test the Apache configuration before restarting it and inspect the service journal for errors.

sudo apache2ctl configtest
sudo journalctl -u apache2 -n 50 --no-pager

A PHP extension is missing

Install the corresponding Ubuntu PHP extension package, then verify it with php -m. If the website uses PHP-FPM or Apache’s module, restart the relevant service after installing or enabling the extension.

Conclusion

You have installed PHP on Ubuntu 26.04, added common extensions, and learned how to configure it with Apache or Nginx. You have also verified PHP execution, inspected its configuration, and reviewed essential security practices.

For a development machine, this is a useful starting point for building PHP applications. For a production server, continue by configuring your domain, HTTPS, application-specific dependencies, database access, backups, logging, and a regular security-update process.

Official References

• Ubuntu Server documentation: Install and configure PHP
• Ubuntu 26.04 PHP 8.5 package details
• PHP installation and configuration manual
• PHP-FPM official documentation
• PHP security documentation

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