PHP is the abbreviation for a scripting language called Hypertext Preprocessor. This abbreviation PHP stood for Personal Home Page Tool for a long time, which is what it originally was. The scripting language or programming language is based on Perl and C syntax. These programs are indispensable for the creation of dynamic websites and web applications. The hypertext preprocessor is freely available and distributed as free software under the PHP license. PHP is indispensable due to its extensive database support, the integration of Internet protocols and the availability of many function libraries. The software bundle can also include Squid.
How was it distributed and how does PHP work?
At the beginning of 2013, PHP was used on around 244 million websites. The software bundle can also include Squid. In 2015, 82% of websites were governed by this programming language. Hypertext Preprocessor is the most widely used programming language in the world because it is easy to learn and uncomplicated. The program can create websites and is often already installed by web hosts. With the PHP system, the codes can work on the server side. This means that the source code cannot be sent to a web browser. This source code is sent to an interpreter from the web server. The interpreter checks the source code and then sends the output to the browser. This output from the PHP interpreter will also appear at the end. The interpreter sends an HTML document to the browser, which can be generated with PHP with other files such as images and PDF files. The system that executes web applications with a PHP file is 
urgently required. The system must be able to handle the instructions contained in the file. An interface (e.g. ISAPI or CGI) helps the interpreter to execute a server daemon or other server services (e.g. Apache or IIS). A mixture of operating systems such as Linux, Windows and macOS, a web server such as Apache and PHP is called LAMP for Linux. For Windows, the package is called WAMP and for macOS it is called MAMP. The XAMPP project is developing packages that render packages from the Internet harmless. However, these versions can only be used for test environments. Hypertext Preprocessor actually only runs in a web server environment, so PHP is also subject to HTTP. Every PHP page called up contributes to the load on the web server. The interpreter also works with the source code. This increases the load and reduces the response speed. Various bytecode caches are provided to improve the response speed. The caches are provided to temporarily store the program and speed up access the next time the file is called. The PHP program can be used to write scripts that are command line-oriented. These are also independent of the internals. Another free software with the PHP code has been called Hip-Hop since 2010. This was developed after several years of research by Facebook designed to alleviate the 40 percent server load on Facebook.
Sessions with the PHP program
Within an HTTP request, only ordinary variables are available. And only stored files. In the request scope, after the page call, that is, at the end, the Dataor the memory is deleted. If a user has a website This often involves several page views. So-called session variables (session scope) are used to fill a shopping cart in an online store. PHP stores data across sessions, which is a standard configuration (application scope). These are stored on the server in other ways so that the content of the virtual shopping cart is not lost each time a new page is called up.
