Desktop Environment vs Window Manager

Desktop Environments and Window Managers are used as part of a graphical environment on Linux and other Unix-like operating systems.

Definition

Window managers facilitate the process of showing more than one graphical application on-screen at one time. A desktop environment is not the same as a window manager.

Desktop environments include a window manager, and typically include a lot of related tools as well. For instance, they usually include a menu or "dock" allowing the user to launch applications and switch between running applications using just the mouse. Also, desktop environments generally include a clock, a tool for managing wired and wireless network connections, and a file manager.

On Ready-Made Distributions

For an end user who has just installed a desktop Linux distribution, the difference between a window manager and a desktop environment may seem irrelevant. Linux Mint KDE includes the KDE desktop environment and Linux Mint Fluxbox includes the Fluxbox window manager. But BOTH of them include the tools you'd expect to find on a desktop environment, such as a file manager and a wired / wireless network manager. Since both editions of Linux Mint contain such tools, it might seem like a window manager and a desktop environment are interchangeable. The end user may or may not care that all of the KDE tools were created for KDE, (and there is a group of people making sure that all these tools provide a consistent user experience and look) while, by contrast, the tools being used alongside Fluxbox were not made to look like each other, and are probably designed to work with any desktop environment or window manager.

Adding to an Existing Distribution

Installing a desktop environment like KDE or LXDE on a Linux system (which could be a basic command-line only system, or a system with another graphical environment) should be pretty easy. Using a tool like YUM or APT (or a graphical interface that serves a similar purpose), the user can install the desktop environment and the system will install the things that desktop environment includes: volume contol tool, network manager, etc. The system will then give you a way to start the desktop environment.

Adding a window manager isn't so simple. If you use a window manager by itself, it won't include the tools that are used to launch and switch applications with the mouse, or a file manager, etc. If you want those tools, you'll end up installing them yourself (and then adding them to the applications that run at startup, if you want).

And if you take a desktop environment like LXDE and replace the window manager with a different one, certain features in the original desktop environment are likely to be broken unless you take additional steps to fix them.