The
name of a
file. All files have names. Different
operating systems impose different restrictions on filenames. Most operating systems, for example, prohibit the use of certain
characters in a filename and impose a limit on the length of a filename. In addition, many
systems, including
DOS and
UNIX, allow a filename
extension that consists of one or more characters following the proper filename. The
filename extension usually indicates what type of file it is.
Within a single directory, filenames must be unique. However, two files in different directories may have the same name. Some operating systems, such as UNIX and the Macintosh operating system, allow a file to have more than one name, called an alias. (In Unix, aliases are called links or symbolic links.)
See the Data Formats and Their File Extensions page in the quick reference section of Webopedia for a list of file extensions and the programs they coincide with.
