PHP installation on Ubuntu

https://help.ubuntu.com/10.04/serverguide/C/php5.html

PHP5 - Scripting Language

PHP is a general-purpose scripting language suited for Web development. The PHP script can be embedded into HTML. This section explains how to install and configure PHP5 in Ubuntu System with Apache2 and MySQL.
This section assumes you have installed and configured Apache2 Web Server and MySQL Database Server. You can refer to Apache2 section and MySQL sections in this document to install and configure Apache2 and MySQL respectively.

Installation

The PHP5 is available in Ubuntu Linux.

• To install PHP5 you can enter the following command in the terminal prompt:
  

  sudo apt-get install php5 libapache2-mod-php5

  
  You can run PHP5 scripts from command line. To run PHP5 scripts from command line you should install php5-cli package. To install php5-cli you can enter the following command in the terminal prompt:
  

  sudo apt-get install php5-cli

  
  You can also execute PHP5 scripts without installing PHP5 Apache module. To accomplish this, you should install php5-cgi package. You can run the following command in a terminal prompt to install php5-cgi package:
  

  sudo apt-get install php5-cgi

  
  To use MySQL with PHP5 you should install php5-mysql package. To install php5-mysql you can enter the following command in the terminal prompt:
  

  sudo apt-get install php5-mysql

  
  Similarly, to use PostgreSQL with PHP5 you should install php5-pgsql package. To install php5-pgsql you can enter the following command in the terminal prompt:
  

  sudo apt-get install php5-pgsql

  
  

Configuration

Once you install PHP5, you can run PHP5 scripts from your web browser. If you have installed php5-cli package, you can run PHP5 scripts from your command prompt.
By default, the Apache 2 Web server is configured to run PHP5 scripts. In other words, the PHP5 module is enabled in Apache2 Web server automatically when you install the module. Please verify if the files /etc/apache2/mods-enabled/php5.conf and /etc/apache2/mods-enabled/php5.load exist. If they do not exists, you can enable the module using a2enmod command.
Once you install PHP5 related packages and enabled PHP5 Apache 2 module, you should restart Apache2 Web server to run PHP5 scripts. You can run the following command at a terminal prompt to restart your web server:

sudo /etc/init.d/apache2 restart 

Testing

To verify your installation, you can run following PHP5 phpinfo script:

phpinfo();
?>

You can save the content in a file phpinfo.php and place it under DocumentRoot directory of Apache2 Web server. When point your browser to http://hostname/phpinfo.php, it would display values of various PHP5 configuration parameters.