What is it?
In recent weeks, Hot Skills has covered a number of server-side, cross-platform, HTML embedded scripting languages which are used to create interactive Web sites, most recently Microsoft's Active Server Pages (ASP). PHP - Personal Home Page tools - is another of them. Unlike the Microsoft product it's open source software, and it's free. You don't pay for ASP either, but you have to buy into Microsoft technologies to get it. Also, since PHP is supported by its developers and users, you don't have to pay to get your questions answered, as you do with ASP.
Where did it originate?
PHP was created in 1994 by Rasmus Lerdorf to keep track of who was looking at his online CV.
In 1995, with additional functionality, including the ability to interpret HTML form data, and support for the mSQL database, PHP went public. Just like Linux, PHP was taken up by an enthusiastic community of open source users, who added their own code to it.
By mid-1997 it was used on over 50,000 Web sites around the world.While it's impossible to keep track, there are probably more than 1,000,000 Web sites using PHP today. Until this year, it was restricted to the Apache Web server, but now it's available for a much wider range.
What's it for?
Like other scripting languages, it's used to generate dynamic Web pages and collect form data. But unlike more heavyweight languages, you simply write HTML scripts with embedded PHP code to do the dynamic stuff. PHP pages can be linked to a wide range of databases including Oracle, Sybase, Informix, Interbase and PostgresSQL.
What makes it special?
PHP's following has grown up among people who don't want to be tied to Microsoft, and who think Perl is too hard to learn and work with. It has a built-in database integration layer and seamless IP connectivity. And you can move PHP from one operating system to another relatively painlessly.
There are ASP-to-PHP conversion tools for those who want to leave Microsoft behind.
Unix, Linux, Windows.
How difficult is it to master?
Easy, with a working knowledge of HTML.
Where is it used?
On Web sites around the world.
Not to be compared with
Perl or Python, unless you are exceptionally brave - all these scripting languages have fiercely loyal followings.
Few people know that
Authoring open source software can make you rich. Linus Torvalds, who has never personally sold a line of code, is now a millionaire, thanks to stock allocations from companies which sell commercial implementations of Linux.
What's coming up?
PHP Version 4.0, with support for a wider range of Web servers, was released in May, followed by a series of bug fixes, new features and performance enhancements, including better stability for Windows.
You can download PHP4 from the official PHP Web site. There are plenty tutorials, hints and tips and sample code on the Web. Two of the most useful, with links to other sites, are www.perfect.co.uk and www.devshed.com. There are plenty of books on PHP, including Professional PHP Programming, available from www.greymatter.co.uk. Try also O'Reilly & Associates.
Rates of pay
Depending on experience, with PHP you could look for between £30,000 and £40,000. There are plenty of cross-training offers too, with some employers looking for people with Visual Basic and ASP experience willing to gain PHP, and people with PHP wanting to learn XML.