In DOS and some other file systems,
filenames often have the form
example, Lotus 1-2-3 files have extensions such as .wk1.
The operating system treats the extension as separate from the
filename and has rules about how long it must be, and so forth.
Table 1.2 lists some of the extensions you might see to filenames, and a brief description of the programs that recognize them.
|.a||Archive file (library)|
|.f||FORTRAN program source file|
|.F||FORTRAN program source file to preprocess|
|.html||HTML file for World Wide Web servers|
|.s||Assembly language code|
|.1 to .8||source file|
In Table 1.3 are some extensions that are often used by users to signal the contents of a file, but are not actually recognized by the programs themselves.
|.txt||ASCII text file|
|.mm||Text file containing troff's|
|.ms||Text file containing troff's|
|.ps||PostScript source file|