NDOS

4DOS

Developer(s)	JP Software
Stable release	8.00 (Open Source in 2009) / 7.50.130 (JPSoft in 2004)
Operating system	DOS, Windows
Type	Command shell
License	modified MIT License that does not qualify as open source by Open Source Initiative or Free Software Foundation standards
Website	4dos.info

4DOS is a command line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in DOS and Windows 95/98/SE/ME. 4OS2 and 4NT replace CMD.EXE in OS/2 and Windows NT respectively. 4DOS was written by Rex Conn and Tom Rawson; it was first released in 1989. These programs can also be initiated from the command line and/or called by scripts.

4DOS is most often used with the MS-DOS-Windows 95 stream of operating systems and it can be also used with Windows NT type machines, IBM PC DOS and also later DR DOS versions. Since Windows NT-2000 includes both COMMAND.COM and CMD.EXE, 4DOS and 4NT and derivatives can both be installed. Earlier versions of 4OS2 can be run under Windows NT, and OS/2 can run the two MS-DOS and Windows NT shells, all three can be used on Windows NT-type machines and OS/2 multiple boot machines.

Among the many commands, statements and functions in 4DOS and lacking in MS-DOS/Windows 95/98 COMMAND.COM are reading keyboard input and a simpler method of working with colors of screen and text.

The default file extension for 4DOS scripts is .btm.

A graphical version of 4DOS, 4OS2, and 4NT, called Take Command, was released with a feature set corresponding to version 4DOS 5.5, 4OS2, and 4NT 2.5 and updated after this. Development on this line stopped with the corresponding character-mode versions. There was a graphical program Take Command/16, for Windows 3.1.