backslash

The backslash symbol (\) is used as a separator between folder and file names in DOS, Windows and OS/2 when the full path to a file is written out. For example, the path c:\cde\cde.exe points to the CDE.EXE file in the CDE folder on the C: drive.

When the universal naming convention (UNC) is used, double backslash (\\) characters serve as a prefix to the server name (see UNC).

In DOS and Windows programming, double backslash characters (\\) represent an actual single backslash that will be displayed or printed. This is required since the symbol is used to separate names and also define hexadecimal numbers.

Just the Worst!
The backslash character was the worst symbol that could ever have been chosen for this purpose. Not only is the backslash key not located in a standard place on the keyboard, but Internet addresses use forward slashes since they come from Unix. The irony is that the DOS path syntax was copied from Unix, but somebody must have felt compelled to show originality of authorship and thus reversed the separator symbols. Now both methods are in our faces day after day. See path.

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(character)

backslash - "\" ASCII code 92. Common names: escape (from C/Unix); reverse slash; slosh; backslant; backwhack. Rare: bash; ITU-T: reverse slant; reversed virgule; INTERCAL: backslat. Backslash is used to separate components in MS-DOS pathnames, and to introduce special character sequence in C and Unix strings, e.g. "\n" for newline.