Backslash (\) Versus Forward Slash (/)

A number of readers have noted recently that I’ve been using the forward slash (/) more and more often in my books to denote hard drive paths. Of course, when working on Windows systems (and DOS before that) it’s common practice to use the backslash (\) for paths. However, using a forward slash has certain benefits, not the least of which is portability. It turns out that the forward slash works well on other platforms and that it also works on Windows systems without problem (at least in most cases). Using a forward slash whenever possible means that your path will work equally well on Windows, Mac, Linux, and other platforms without modification.

In addition, when working with languages such as C++, JavaScript, Java, and even C#, you must exercise care when using the backslash because the languages use it as an escape character (a character pair that denotes something special). For example, using \n defines a newline character and \r is a carriage return. In order to create a backslash, you must actually use two of them \\. The potential for error is relatively high in this case. Forward slashes appear singly, so you can copy them directly, rather than manipulating the path in various ways.

There are situations where you must use a backslash in the Windows (and also the DOS) environment. You can type CD / or CD \ and get to the root directory of a Windows system. However if you try to type Dir /, you’ll get an error. In order to obtain a directory listing of the root directory, you must type Dir \ instead. In fact, many native utilities require that you use the backslash for input. On the other hand, many Windows APIs accept the forward slash without problem. When in doubt, try both slashes to see which works without problem. If you see a forward slash used in one of my books, the forward slash will definitely work in that instance. In general, I only use the forward slash when compatibility with other platforms is a consideration. Windows-specific platform information will still use the backslash.

As things stand today, the more you can do to make your applications run on multiple platforms, the better off you’ll be. Users don’t just rely on Windows any longer—they rely on a range of platforms that you might be called upon to support. Having something like an incorrectly formatted path in your code is easy to overlook, but devastating in its effects on the usability of your application.

Let me know your concerns about the use of backslashes and forward slashes in my books at The book that uses the largest number of forward slashes for paths right now is C++ All-In-One Desk Reference For Dummies. I want to be sure everyone is comfortable with my use of these special symbols and understands why I’ve used one or the other in a particular circumstance.