PHP QuickStart Guide (2015)
Chapter 2: What Is PHP?
What the Name Means
When PHP originated in 1994, the acronym represented the term “Personal Home Page.” This was because its developer, Rasmus Lerdorf simply created a set of Common Gateway Interface (CGI) functions written in the C programming language to simplify managing his own web page. Today, after an incredible amount of functionality has been added, the generally accepted meaning of PHP is “Hypertext Preprocessor.” This refers to PHP's ability to process the contents of a web page, form or other document before outputting the results to a browser.
The Evolution of a Language
PHP is a high-level programming language. It shares some syntactical similarities with the C, Perl and Java languages. PHP is open-source software, meaning that the core software can be used, exchanged, modified, and implemented by anyone, free of charge.
One of the many unique things about PHP is that it wasn't conceived as a programming language. Rather, it was originally released to the public as a set of tools for web site maintenance. Forms handling and database functions were added soon after following the formation of a development team, which caused the language to grow at an unprecedented rate. Today, thanks to its open source status, independent developers around the world continue to develop and contributed to it.
What it's Used For
PHP is designed primarily for web applications. However, depending on its implementation, it can be used for desktop applications and more. It's most commonly used for server-side applications and can be embedded directly in web page code. It can also output HTML code.
One of the most powerful features of PHP is its ability to write to and extract data from online databases. This capability is easily used to create custom web pages on demand and update records via user input. Several modules in the core allow interaction with almost any database software. This feature has been widely used as the basis for several popular Content Management Systems (CMS), including WordPress, Joomla, Drupal and others. It has also been used to create scores of other web-based software packages to handle everything from client and team management to hosting server management.
Web developers use PHP and its modules to create custom applications for websites. In addition to database functions, it can be used to manipulate input and output from web forms, provide information directly from web servers such as date, time, etc. and provide interaction with other sites, such as payment gateways.