I’ve seen references to both “COMMAND.COM” and “CMD.EXE” as being called “the DOS prompt” in Windows XP. When I run each, via Start-Run, they seem similar, and yet I can tell that there are differences. For example I can’t figure out how to “CD” to the “Program Files” directory using COMMAND.COM. What are they, and which should I use?
My advice is simple: forget about COMMAND.COM. It has a long, and venerable history, but for most practical purposes, it’s no longer needed.
Understanding why is a trip down memory lane for MS-DOS and Windows.
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As you probably know, MS-DOS was the predecessor to Windows. It was character mode only, and you ran programs by typing their name at the command prompt. MS-DOS was created when 16 bit processors were becoming popular, and its widespread adoption is credited with kick starting the rise in popularity of the personal computer.
Then two things happened: Windows, and 32 bit processors. Fast forward to today, and MS-DOS has pretty much disappeared from the landscape – Windows, and its rich graphical interface, is everywhere. The same is true for the 16bit processor. Most all contemporary machines are built on various flavors of 32bit processors.
What does all that have to do with COMMAND.COM and CMD.EXE? It’s quite simple really: CMD.EXE is a command line processor for 32bit Windows. Much like MS-DOS before it, it provides a character-mode only user interface into which you can type commands to run programs. CMD.EXE is a 32 bit program that is fully a part of Windows – in fact it’s what gets run when you select Command Prompt on the Windows Accessories menu.
COMMAND.COM, on the other hand, exists only for compatibility and 16bit programs. It exists solely for those programs which have not been updated since the days of MS-DOS. It’s designed to run 16bit applications, and operates just like the old MS-DOS did.
On the surface, they’re very similar. Even though CMD.EXE was a complete re-write, it’s based on the same concepts and similar syntax. But the differences become quickly apparent. Let’s used your “CD” example from above.
In CMD.EXE, you can change to the “Program files” directory by doing this:
cd "\Program Files"
Note the quotes around the directory name. Try doing that in COMMAND.COM and you’ll get this:
cd "\Program Files" Parameter format not correct - "\program
The problem is COMMAND.COM doesn’t know about long file names (filenames longer than 8.3) or filenames that have spaces in them, and it doesn’t have a way to quote the name. So if you still need to, how do you CD to that directory in COMMAND.COM? Well, first you need to find out the alternate, 8.3 name of that directory … its short name:
dir /x Directory of C:\ 08/21/2005 09:50 AM <DIR> PROGRA~1 Program Files
(I’ve removed some of the lines of output for brevity.) The “/X” parameter to DIR tells it to include the “shortname” in the output. In this case that’s “PROGRA~1”, a machine generated alternative name for “PROGRAM FILES”. Now we can CD to that in COMMAND.COM:
cd progra~1 dir Volume in drive C is Volume Serial Number is B026-62CA Directory of C:\PROGRA~1 08/21/2005 09:50 AM <DIR> . 08/21/2005 09:50 AM <DIR> .. 03/24/2005 04:42 PM <DIR> Adobe ...etc...
The bottom line is actually quite simple: use CMD.EXE unless you know you need COMMAND.COM for compatibility with some older 16bit program. And even then, if you try and run a 16 bit program in CMD.EXE, it will typically run it within COMMAND.COM for you anyway, so you still may not need to know or care.
And in case you’re wondering, yes … something similar is coming down the road as 64 bit processors begin to arrive. The 64bit version of Windows does, I believe, include another command processor, one for native 64bit command-line programs.
Simply Wow! You really solved my lots of problems
Thankx
Excellent stuff. It gave me a clear idea of both.
Thanks.
it cleared my doubt in an instance 🙂
Amazingly ,in few lines you cleared all.
Thanks for the detailed Information !!
thanks a lot!!!
Nice explaination. Short and sweet 😀
Perfect, and to the dot.
good very nice, cleared my doubt for long
Really a nice explanation! Thanks
For the past 2 hours I am trying to access ‘my documents’ with the command prompt and was frustatingly reaching nowhere. You cleared it within one minute :)……..You are great, thanks a million 😀
I have a friend that is getting a command.com type error approximately 1 minute after bootup, while sitting at the desktop . error is: c:\windows\system32\configuration\command.com Parameter not correct c:\document
Obviously cannot find the “documents and settings” folder. What would cause command.com to start up and be giving this error. It is a WinXP system. Leo, can you or anyone else explain this to me?
that’s cuz some shortcut is pointing to ‘documents and settings’ trough command.exe, try to find the shortcut file, then edit it and change the name to docume~1 or whatever it is.
what is the difference between directory and command
Thanks Nice explaination
One thing you do NOT get “off the shelf” with ‘cmd.exe’ is the ‘history’ though’. ‘command.com’ just keeps on going, going, going.
With ‘cmd.exe’ you have to tweak it to see, not what you typed, but what the output was. If you start a program or a batch job which results in thousands of lines of feedback…. initially you will have a problem with cmd.exe. NOT with command.com.
‘command.com’ does it good-old-style DOS ways…. it just keeps on going. IOW you can just scroll back and back and back. No fancy-pancy true-type fonts though.
I didn’t try it, but I guess that if you exeed the 64kB segment command.com will submit to failure.
command.com doesn’t maintain a history of the commands run previously (in the same session of course!) , whereas cmd.exe maintains a relly long (configurable) history
Wow, thanks much for the tech note. Gets very frustrating when you know something is supposed to work, but it does not and you can quickly search and find a fast solution. Wish all of computer life were this easy 🙂 ~SL
if i open cmd.exe is it still possible to get
cd progra~1
Directory of C:\PROGRA~1
is this possible in cmd.exe ?
command.com can still be extremely useful for running applications when a pc is infected with malware. A lot of the malware prevents cmd.exe but not command.com.
WHAT IS THE USE OF CMD.EXE EXACTLY?
Wow great article. I kept having problems with CD and had no idea it was bcus i was using command. Now I know it more than just cd, I had no idea it was an entirely different processor!
when there is space in file name, the command was used “Path of 1.dwg”, this syntax will help to incorporate the spaces in file and it works on 32bit windows xp, and it doesnt work on windows7 64 bit system32.cmd.exe and on system64.cmd.exe windows 7