4DOS (ver 7.50) Freeware This is the last version of 4DOS released by JP Software. 4DOS.com is a Command Line Interpretor, and an enhanced direct replacement for the IBM/Microsoft Command.com Command Line Interpretor. 4DOS works with all known varients of 16-bit DOS. 4DOS also supports the Regina REXX batch language interpretor. ----- To replace Command.com as the CLI interpretor, add this line to your Config.sys file (change path and environment size as appropriate) -> shell=C:\4DOS\4dos.com C:\4DOS /E:640 /P .