PHP is a powerful open source server-sided scripting language that can be used on a wide variety of operating systems and webservers, including Apache on UNIX and IIS on Windows.
PHP contains numerous extensions which enable you to dynamically create images and flash files, parse xml, connect to remote servers using pop, imap, ftp, http and raw sockets, natively access many database servers including PostgreSql, MySQL and Microsoft SQL Server, compress and decompress files, lookup domain names and and much more.
PHP has an excellent manual and online documentation which covers every function for every extension available.
If you are getting the "Fatal error: Call to undefined function imap_open()" error in PHP when using the IMAP functions then they are not installed with your installation of PHP. This post looks at how to install the PHP IMAP functions on CentOS and should also work for Red Hat Enterprise Linux (RHEL), Fedora and other derived Linux distros.
As well as running PHP scripts via a web server such as Apache, you can also run PHP scripts from the command line (it’s also possible to write GUI apps with PHP using PHP-GTK, but I’ll maybe look at that another time). This post looks at the two ways you can run a PHP script from a *nix based computer (Linux, Unix, BSD, OSX) and the single way you can do it from Windows.
Sometimes you may need to get the first sentence from a block of content for use as e.g. the meta description for a page. This post looks at how to get the first sentence using PHP.
Yesterday I looked at how to copy a table with MySQL using some SQL queries. This post looks at how to automate the process with a PHP script saving you having to type in and adjust queries each time you want to back up a table.
The Zend Framework has a component called the Zend_Registry which allows you to store data into a sort of global space which lasts the duration of the script. Once saved to the registry the data is available throughout the application. This post shows how to save some data to the registry and then retrieve it.
The PHP function is_callable() tests to see if a function or class method can be called, and solves an issue with the method_exists() function which will return true for all methods regardless of whether or not they can actually be called.