DOS Tips

Hidden COMMAND.COM Switches

To get the list of the whole COMMAND.COM switch, type the /? the command prompt. But the thing is, we now have 3 switches that are not documented at all, not even under the /? list. So, now let us have a brief explanation.

The first switch is the /D switch. COMMAND /D used on the CONFIG.SYS SHELL= line (the primary shell), or at the MS-DOS prompt (secondary shell in combination with the COMMAND /P parameter), prevents the execution of the AUTOEXEC.BAT file at bootup. Example:

SHELL=C:\COMMAND.COM C:\ /E:512 /D /P

The next switch is the /F. Remember the annoying "Abort,Retry, Fail" error? Most of us usually just select "Fail". This is exactly what the switch does - it will automatically reply with a "Fail" if the floppy disk drive is not ready or available. You can activate it on the CONFIG.SYS file SHELL= line. Example:

SHELL=C:\COMMAND.COM C:\ /E:512 /F /P

or just added to any PIF file or the DOS Prompt shortcut through "Command.Com /F"

The third switch is th /Z. This will display "errorlevel" return code messages after executing each external DOS command - which is normally used to examine the return code for use of batch files. This switch can be activated through the CONFIG.SYS file SHELL= line. Example:

SHELL=C:\COMMAND.COM C:\ /E:512 /P /Z

It can also be used in a Windows PIF file. You should see the below message:

"Microsoft(R) Windows 95
(C)Copyright Microsoft Corp 1981-1996.
Return code (ERRORLEVEL): 0
WARNING: Reloaded COMMAND.COM transient"

Dos Tips 10

Return to the Tips index

Dos Tips 12

Copyright (C) 1998-1999 The Active Network. All rights reserved.
Please click here for full terms of use and restrictions.