MySQL command line allows you to manage your database environment through your terminal, or command prompt for Windows. Typically when you set up a web server you would have installed MySQL as its own service and can easily access the MySQL command line via mysql (mysql.exe). However in a development situation you may have used XAMPP which bundles it all together for you and you can't just access the XAMPP MySQL command line through a registered path.
I've been using Vagrant at work for a few months now - and I got into it specifically for mimicking our product environment. If you don't know about Vagrant, I highly suggest you check it out. I recently purchased an iMac and I'm utilizing Vagrant VMs for all development. That means I have a few select environments and my machine is bogged down with extra services or dependency issues.
With the new wave of mobile devices being a major way to access the Internet, it has become possible to customize web applications based on a user's location - or create web applications based on user location. This example will show you how to get a user's location, pull up a static Google Map, and the query a database for locations within one mile of the user's location.
The easiest way to learn PHP is to be able to create and edit code and see instant results. When I was younger and learning I couldn't afford to have my own web server so I installed a WAMP environment - I also didn't have a spare machine laying around to toss Linux on. Unfortunately I never heard of EasyPHP until a bit ago, it was originally released in 1999, but you can Wikipedia that.