PHP ain’t just for Web sites

LinuxJournal’s Marco Tabini says, “If PHP is your scripting language of choice when it comes to developing dynamic Web sites, you probably have grown to love its immediacy and power. An estimated ten million Web sites use at least some PHP scripting to generate their pages.” But don’t stop reading there.

Marco continues, “Although most people use PHP primarily as a Web development scripting system, it possesses all the characteristics of a proper general-purpose language that can be useful in a variety of other environments. In this article, I illustrate how it’s possible to use the command-line version of PHP to perform complex shell operations, such as manipulating data files, reading and parsing remote XML documents and scheduling important tasks through cron.

The contents of this article are based on the latest version of PHP at the time of this writing, 4.3.0, which was released at the end of 2002. However, you should be able to use older versions of PHP 4 without many problems. I explain the differences you may encounter as necessary.” This article is not intended for novices. “Although the news aggregator script I present in this article performs a rather complex set of functions—from grabbing content off the Web to parsing XML and formatting it in HTML—it requires only about 200 lines of code, including all the comments and blank lines. It is possible to write the same script in Perl or even as a shell script, with the help of some external applications such as wget, expat and sendmail. The latter approach, in my opinion, results in a complicated code base with plenty of opportunities for mistakes.

PHP-CLI rarely is installed by default on a machine running Linux, although you can count on Perl being readily available. Thus, if you have control over the make-up of the server on which you’re running scripts and you’re comfortable with PHP, there’s no reason why you need to learn another language to write most of your shell applications. If, on the other hand, you’re writing code to run on a separate machine over which you have no control, you may find PHP a slightly more problematic choice.”