Added section on Command Line Interface

PHP's command line interface is a simple, powerful way to automate common tasks. New PHP programmers often do not take advantage of PHP's CLI capabilities because they only think of PHP scripts as something that must run in the browser over HTTP. A simple, gentle introduction to running PHP scripts from the command line will help raise awareness that you can accomplish powerful, admin-only tasks through simple PHP scripts without having to craft a UI or open it up to the security issues of the web.

_includes/command-line-interface.md

@@ -0,0 +1,45 @@
+# Command Line Interface
+
+PHP was created primarily to write web applications, but it's also useful for scripting command line interface (CLI) programs, too. Command line PHP programs can help you automate common tasks like testing, deployment, and application administrativia. 
+
+CLI PHP programs are powerful because you can use your app's code directly without having to create and secure a web GUI for it. Just be sure not to put your CLI PHP scripts in your public web root!
+
+Try running PHP from your command line:
+
+    > php -i
+
+The `-i` option will print your PHP configuration just like the [`phpinfo`][0] function. There are a number of other useful [command line options][1], too.
+
+Let's write a simple "Hello, $name" CLI program. To try it out, create a file named `hello.php`, as below.
+
+    <?php
+    if($argc != 2) {
+        die("Usage: php hello.php [name].\n");
+    }
+    $name = $argv[1];
+    echo "Hello, $name\n";
+
+PHP sets up two special variables based on the arguments your script is run with. [`$argc`][2] is an integer variable containing the argument *count* and [`$argv`][3] is an array variable containing each argument's *value*. The first argument is always the name of your PHP script file, in this case `hello.php`.
+    
+To run our script, above, from the command line:
+
+    > php hello.php
+    Usage: php hello.php [name]
+    > php hello.php world
+    Hello, world
+
+## Built-in, command line web server
+
+Starting with PHP 5.4, you can develop locally on a PHP-enabled web server without the hassle of installing and configuring a full-fledged web server. To start the server, from your web root:
+
+    > php -S localhost:8000
+
+ * [Learn about running PHP from the command line][5]
+ * [Learn about the built-in, command line web server][4]
+
+[0]: http://php.net/manual/en/function.phpinfo.php
+[1]: http://www.php.net/manual/en/features.commandline.options.php
+[2]: http://php.net/manual/en/reserved.variables.argc.php
+[3]: http://php.net/manual/en/reserved.variables.argv.php
+[4]: http://www.php.net/manual/en/features.commandline.webserver.php
+[5]: http://php.net/manual/en/features.commandline.php

_layouts/default.html

@@ -39,6 +39,7 @@
                     <li><a href="#password_hashing_with_bcrypt">Password Hashing with Bcrypt</a></li>
                     <li><a href="#dependency_management">Dependency Management</a></li>
                     <li><a href="#web_application_security">Web Application Security</a></li>
+                    <li><a href="#command_line_interface">Command Line Interface</a></li>
                     <li><a href="#popular_frameworks">Popular Frameworks</a></li>
                     <li><a href="#links_and_resources">Links &amp; Resources</a></li>
                 </ul>

index.html

@@ -26,6 +26,9 @@ layout: default
 {% capture security_content %}{% include web-application-security.md %}{% endcapture %}
 {{ security_content|markdownify }}
 
+{% capture cli_content %}{% include command-line-interface.md %}{% endcapture %}
+{{ cli_content|markdownify }}
+
 {% capture frameworks_content %}{% include popular-frameworks.md %}{% endcapture %}
 {{ frameworks_content|markdownify }}