Jim said:
No. It is a command line interpreter. In short, it accepts a string from
the user and then
determines which program to run and which switches to apply. It also has
the ability
to redirect the output to a user defined file.
Cmd.exe is also a command line interpreter. Someone else will doubtless
tell us the
differences between these two programs.
Command.com is the 16-bit command processor for 16-bit DOS applications,
or more precisely it is the command processor for the NT Virtual DOS
Machine (NTVDM), as with all 16-bit applications Command.com runs inside
the NTVDM.
Cmd.exe is the native NT 32-bit command processor. The Command.com that
ships with NT operating systems is not the same as the one in DOS/Win9x
operating systems, it is a special version. The NT version of
Command.com prepares and passes all of the commands it receives to
Cmd.exe for execution. That is why the two CLI's appear seemingly to be
able to run the same commands, they are because Cmd.exe runs the
commands for Command.com so in fact Command.com can take advantage of
the commands available with Cmd.exe.
If you want to see the above in action start the the Task Manager (or
Process Explorer) and then launch Command.com and you will see the NTVDM
start in the Task Manager, you will not see Command.com. Now, give a
bit of work to the Command.com 16-bit processor and keep an eye on the
Task Manager and you will see Cmd.exe appear and then disappear when it
executes the command it received from Command.com. If the amount of
work to do is too little you won't see CMD.EXE appear in the Task
Manager, the work will be over before Task Manager responds. A good
command to run to see this would be the DIR /s command from the root folder:
cd\
dir /s
The dir/s command will list all the files on the volume, to stop the
output of the dir /s command press Ctrl+Break. Once and for all that
should dispel the notion that some hold that there is DOS in NT
operating systems.
John