Edlin
Edlin is a line editor, and the only text editor provided with early versions of MS-DOS. Although superseded in MS-DOS 5.0 and later by the full-screen edit command, and by Notepad in Microsoft Windows, it continues to be included in the 32-bit versions of current Microsoft operating systems.
History
Edlin was created by Tim Paterson in two weeks in 1980, for Seattle Computer Products's 86-DOS (QDOS) based on the CP/M line editor ED.
Microsoft acquired 86-DOS and sold it as MS-DOS, so Edlin was included in v1.0–v5.0 of MS-DOS, after which the only editor included was the new full-screen EDIT.EXE in v6.0–v8.0.
Early Windows versions ran on top of the later versions of MS-DOS, so Edlin was typically not available.
However, Edlin is included in the 32-bit versions of Windows NT and its derivatives—up to and including Windows 8—because the NTVDM's DOS support in those operating systems is based on MS-DOS version 5.0. However, unlike most other external DOS commands, it has not been transformed into a native Win32 program. It also does not support long filenames, which were not added to MS-DOS and MS-Windows until long after Edlin was written.