On a computer the dollar sign ($) is the symbol found above the 4 key on United States qwerty keyboard that is used to represent a US currency value, e.g. $10.00 for ten dollars.
In computer programming languages, the dollar sign has been used for many purposes. With programming languages like BASIC, Pascal, and PHP, the dollar sign is used for the defining of variables and constants. ALGOL 68 and TeX typesetting languages use the dollar sign for delimiting transput format and mathematical regions. ASP.NET uses the dollar sign to indicate an expression is to follow, when used within the tag of a web page.
The dollar sign is also used in various computer applications, including operating systems and Microsoft Excel. In the Windows operating system, the dollar sign is used to hide shared folders, by adding the dollar sign to the end of a shared folder name. In Excel and other spreadsheet programs, the dollar sign is used in formulas to denote an absolute cell reference (e.g., =$D$4*A3). It has also been used to indicate the end of a line or file in text editors.