After The Command Line Scripting is Done You Need

PHP is mainly focused on server-side scripting, so you can do anything that any other CGI program can do, such as collect form data, generate dynamic Web page content, or send and receive cookies. PHP is also good at database access, disk access, networking, and textrnmanipulation.

Server-side scripting is the most traditional and main target field for PHP. You needrnthree things to make this work. The PHP interpreter (as a server module or CGI), a Web server, and a Web browser. You need to run the Web server with PHP enabled. Then, comes the Command line scripting. You can make a PHP script to run it without any server or browser.
You only need the PHP interpreter to use it. This type of usage is ideal for scripts regularly executed using ‘cron’ (on UNIX or Linux) or Task Scheduler (on Windows). These scripts can also be used for simple text processing tasks.

After the command line scripting is done you need to write client-side GUI applications. PHP is probably not the very best language to write windowing applications, but if you know PHP very well and would like to use some advanced PHP features in your client-side applications, you can also use PHP-GTK (an extension to PHP; not available in the main distribution) to write such programs.

With PHP, you are not limited to output HTML. PHP's abilities include outputting images, PDF files, and even Flash movies. You can also output easily any text, such as XML file. PHP also has support for talking to other services using protocols such as LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM (on Windows) and countless others.

One of the strongest and most significant feature of PHP is its native database support for a wide range of databases (MySQL, mSQL, Oracle, Sybase, Informix, Direct MS-SQL, PostgreSQL, Unix dbm, IBM DB2, dBase, InterBase, FrontBase, Ingres, Hyperwave, Adabas D, Solid, FilePro, Empress, Ovrimos, Velocis), which allows access to the databases directly through SQL statements.

PHP can be used on all major operating systems, including Linux, many Unix variants (including HP-UX, Solaris and OpenBSD), Microsoft Windows, Mac OS X, RISC OS, and probably others. PHP has also support for most of the Web servers today. This includes Apache, Microsoft Internet Information Server, Personal Web Server, Netscape and iPlanet servers, Oreilly Website Pro server, Caudium, Xitami, OmniHTTPd, and many others. The majority of the Web servers have a PHP interpreter module. However, on the other servers supporting the CGI standard, PHP can work as a CGI processor.