4DOS
| 4DOS | |
|---|---|
| Developer(s) | JP Software | 
| Stable release | 8.00 (Source available in 2009)
   /    7.50.130 (JPSoft in 2004) | 
| Operating system | MS-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 MS-DOS and Windows. It was written by Rex C. Conn and Tom Rawson and first released in 1989. Compared to the default, it has a large number of enhancements.
4OS2 and 4NT are similar products that replace cmd.exe in OS/2 and Windows NT respectively.