Chapter 26. Command-Line PHP

Introduction

PHP was created for web programming and is still used mostly for that purpose. However, PHP is also capable as a general-purpose scripting language. Using PHP for scripts you run from the command line is especially helpful when they share code with your web applications. If you have a discussion board on your website, you might want to run a program every few minutes or hours to scan new postings and alert you to any messages that contain certain keywords. Writing this scanning program in PHP lets you share relevant discussion-board code with the main discussion-board application. Not only does this save you time, but it also helps avoid maintenance overhead down the road.

PHP builds include a command-line interface (CLI) version. The CLI binary is similar to web server modules and the CGI binary but has some important differences that make it more shell friendly. Some configuration directives have hardcoded values with CLI; for example, the html_errors directive is set to false, and implicit_flush is set to true. The max_execution_time directive is set to 0, allowing unlimited program runtime. Finally, register_argc_argv is set to true. This means you can look for argument information in $argv and $argc instead of in $_SERVER['argv'] and $_SERVER['argc']. Argument processing is discussed in Parsing Program Arguments and Parsing Program Arguments with getopt.

To run a script, pass the script filename as an argument:

% php scan-discussions.

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