Filename extension

A filename extension is an extra set of (usually) alphanumeric characters that is appended to the end of a filename to allow computer users (as well as various pieces of software on the computer system) to quickly determine the type of data stored in the file. It is one of several popular methods for distinguishing between file formats.

Related Topics:
Alphanumeric - Character - Filename - Software - File format

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

File managers such as Windows Explorer can have applications assigned for almost every file name extension. For example, a text editor for .txt, a word processor for .doc, a web browser for .htm or .html, PDF viewer or editor for .pdf, a graphics program for .png, .gif or .jpg, a spreadsheet program for .xls, etc. Some extensions, including .exe, .com, .bat, and .cmd, indicate that the file itself may be executed under Windows.

Related Topics:
File manager - Windows Explorer - Text editor - Word processor - Web browser - PDF - Graphics program - Spreadsheet

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Filename extensions have been in use for decades, but they have gained common usage because the file systems included with DOS and Windows had severe limitations on filenames for many years. They can be considered as a type of metadata, though one of the most visible pieces of such information on modern computer systems.

Related Topics:
File system - DOS - Windows - Metadata

~ ~ ~ ~ ~ ~ ~ ~ ~ ~