Linux is frequently used on servers that users can access only through a network connection. Typically such servers are used and administered through command line interfaces. However, Linux implementations also provide the X windows system, which makes it possible to run graphical user interfaces on the Linux server but display the corresponding windows on the users' desktop computer.
It works kind of like the Remote Desktop software for Microsoft Windows, but you can have multiple windows. For example, you can open a window for each application you run on the Linux server.
You can display X windows on any computer with any operating system, including Microsoft Windows and Mac OS, as long as an X windows server is stalled on it. Xming is such a server. When installed on your Windows desktop computer, it allows you to display fully functional graphical user interfaces of software running on a remote Linux system.
Xming is free and open source. You can download it from sourceforge. It is straight-forward to install and comes with an "XLaunch" tool, which makes it easy start up X programs on the server that are displayed on the desktop client computer you are sitting at. For example, it takes care of setting the DISPLAY variable on the Linux system that tells X windows where the user interfaces should be displayed.
Xming requires a communications program, such as PuTTY, that links the server to your desktop computer. You will have the option to connect PuTTY to Xming during installation or execution.
The easiest way to start X windows applications is to run the XLaunch program and select "Multiple windows". Next, select "Start a program", and select "xterm" as the program to be started. Then select "Using PuTTY (plink.exe)" and enter the remote server, user name, and password. After finishing the XLaunch wizard an X window running an "xterm" should pop up. From there you can start up more X applications by entering the command in the terminal window. For example to display a clock you would enter "xclock &" at the command line prompt. The "&" starts the process in the background, so that you can continue to enter other commands in the xterm window. Since you selected "Multiple windows", each application will be displayed in its own window.