backslashes

Backslashes, also known as the reverse solidus, are typographic characters used primarily as escape characters in computing and as directory separators in Windows file paths. Their ASCII code is 92 and their Unicode code point is U+005C. In some fonts, the backslash is visually indistinguishable from the Yen symbol, which can cause confusion in Japanese contexts.

In programming, backslashes signal that the following character has a special meaning. They form escape sequences such as newline (\n), tab (\t), a quote (\" or \'), or a literal backslash (\\). This usage appears in languages such as C, C++, Java, C#, Python, and JavaScript, as well as in data formats like JSON and YAML. In regular expressions, backslashes escape metacharacters and can introduce shorthand character classes (for example, \d, \w).

In Unix-like systems, the backslash also serves as a line continuation or as an escape for characters in the shell. In Windows, the backslash is the standard directory separator in file paths (for example C:\Program Files\). Consecutive backslashes have significance in UNC paths, which start with double backslashes to denote network locations (\\server\share).

Usage in other contexts includes typesetting and markup, where in TeX/LaTeX the backslash introduces a control sequence, and in many programming languages serves as an escape for string literals. In URLs the backslash is not a standard path delimiter and is generally encoded as %5C when present.

Common pitfalls include improper escaping, which can lead to syntax errors or security issues such as injection attacks. Practitioners should consider the need for escaping or raw strings in the relevant language or format.