Undocumented DOS commands
Stephen S.
dealt with undocumented DOS commands. I remember it mentioned the
/mbr for FDISK and the TRUENAME command. There were a few others as
well. I now have a class that I would like to share this with but I
can't find my old copy nor can I find information about this on the
internet. Of course MS is no help either!? if you can point me in
the right direction or if you have a copy of the file around plase
email me at ste...@mass-pc.com
Thanx in advance!
Dav1936531
>Date: 1/26/99 9:05 PM Eastern Standard Time
>Message-id: <36b0744b...@news1.banet.net>
>
>A while back (this is like two of three years now) I had a paper that
share this with but I
>can't find my old copy nor can I find information about this on the
>internet. Of course MS is no help either!?
MicroSoft is no help???????? I have MS-DOS on my Windows system and there isn't
even a help file that lists any of the DOS commands. It has been over ten years
since I used DOS and I remember absolutely nothing. Why the idiots at MS don't
put a help file that at least lists the commands and their syntaxes is beyond
me. They are appearently so self assured of their position in the industry that
they just automatically assume that, of course, you must know DOS.
If anybody knows where I can get such a help file for DOS, please let me know.
Thank you in advance.
ManicsMind
Try This:
netstat -a /?
deltree /?
command /?
ect.
It should work with most of the commands you will use. . .
кФФФФП кФФФФП кФФПкП кП кФФФФП
ГеИеИГПГеЭЭИГПГеИГГГПГГПГеЭЭЭОП
ГГГГГГГГГкФГГГГГГРйГГГГГГРФФФПй
дОдОдОГдОГ дОГдОдЭЭОГдОГдЭЭЭЭОП
РйРйРй Рй Рй РйРФФй Рй РФФФФй
MхёэчВ
Insert flame here:
<flame>
</flame>
Larry Weiss
> A while back (this is like two of three years now) I had a paper that
> /mbr for FDISK and the TRUENAME command. There were a few others as
> can't find my old copy nor can I find information about this on the
http://ourworld.compuserve.com/homepages/kevtronics/undoc.txt
Michael J. Gregg
Dav1936531 wrote in message
<19990126234957...@ng-fp1.aol.com>...
>>From: sma...@banet.net (Stephen S.)
>>Date: 1/26/99 9:05 PM Eastern Standard Time
>>Message-id: <36b0744b...@news1.banet.net>
>>
>>A while back (this is like two of three years now) I had a paper that
>>dealt with undocumented DOS commands. I now have a class that I would
like to
>share this with but I
>>can't find my old copy nor can I find information about this on the
>>internet. Of course MS is no help either!?
>
Larry Weiss
> That;s what the /? is for..........
>
That's what it is for, all right, but have you actually compared
the text that you get from "/?" to what you got from HELP ?
The new version is a extreme subset of the older version.
For example look at the HELP text for CHOICE versus the "/?"
output text for CHOICE (listed below). You'll note that the "/?"
text lacks any examples, does not have cross-references to other
commands, contains a very terse description of what the command
actually does and lacks any extra narrative.
I feel that both the terse "/?" and the expanded HELP text should
have been available with Windows 95.
==== CHOICE /? =============================================================
Waits for the user to choose one of a set of choices.
CHOICE [/C[:]choices] [/N] [/S] [/T[:]c,nn] [text]
/C[:]choices Specifies allowable keys. Default is YN
/N Do not display choices and ? at end of prompt string.
/S Treat choice keys as case sensitive.
/T[:]c,nn Default choice to c after nn seconds
text Prompt string to display
ERRORLEVEL is set to offset of key user presses in choices.
===== HELP =================================================================
CHOICE
Prompts the user to make a choice in a batch program. Displays a specified
prompt and pauses for the user to choose from among a specified set of keys.
You can use this command only in batch programs.
For more information on the ERRORLEVEL parameter, see <CHOICE--Note> and the
<IF> command.
Syntax
CHOICE [/C[:]keys] [/N] [/S] [/T[:]c,nn] [text]
Parameters
text
Specifies text you want to be displayed before the prompt. Quotation
marks are necessary only if you include a switch character (/) as part
of the text before the prompt. If you don't specify text, CHOICE
displays only a prompt.
Switches
/C[:]keys
Specifies allowable keys in the prompt. When displayed, the keys will be
separated by commas, will appear in brackets ([]), and will be followed
by a question mark. If you don't specify the /C switch, CHOICE uses YN
as the default. The colon (:) is optional.
/N
Causes CHOICE not to display the prompt. The text before the prompt is
still displayed, however. If you specify the /N switch, the specified
keys are still valid.
/S
Causes CHOICE to be case sensitive. If the /S switch is not specified,
CHOICE will accept either upper or lower case for any of the keys that
the user specifies.
/T[:]c,nn
Causes CHOICE to pause for a specified number of seconds before
defaulting to a specified key. The values for the /T switch are as
follows:
c
Specifies the character to default to after nn seconds. The
character must be in the set of choices specified in the /C switch.
nn
Specifies the number of seconds to pause. Acceptable values are from
0 to 99. If 0 is specified, there will be no pause before
defaulting.
CHOICE--Note
ERRORLEVEL parameters
The first key you assign returns a value of 1, the second a value of 2, the
third a value of 3, and so on. If the user presses a key that is not among
the keys you assigned, CHOICE sounds a warning beep (that is, it sends a
BEL, or 07h, character to the console).
If CHOICE detects an error condition, it returns an ERRORLEVEL value of 255.
If the user presses CTRL+BREAK or CTRL+C, CHOICE returns an ERRORLEVEL value
of 0.
When you use ERRORLEVEL parameters in a batch program, list them in
decreasing order.
CHOICE--Examples
What the user sees when you use CHOICE in a batch file
If you use the following syntax in a batch file,
choice /c:ync
the user sees the following when CHOICE is started:
[Y,N,C]?
If you add text to the syntax,
choice /c:ync Yes, No, or Continue
the user sees the following when CHOICE is started:
Yes, No, or Continue [Y,N,C]?
What the user sees if you leave out a prompt
If, as in the following example, you use the /N switch to leave out the
prompt in a batch program,
choice /n Yes, No, or Continue?
the user sees only the text you specified when CHOICE is started:
Yes, No, or Continue?
What the user sees if you use the T switch
If you use the following syntax in a batch program,
choice /c:ync /t:n,5
the user sees the following when CHOICE is started:
[Y,N,C]?
If, after 5 seconds, the user hasn't pressed a key, CHOICE chooses N and
returns an ERRORLEVEL value of 2. If the user presses a key before 5
seconds, CHOICE returns the value corresponding to the user's choice.
To have the option of defragmenting drive C when you start your computer,
you could add the following lines to your AUTOEXEC.BAT file:
choice Defrag drive /ty,5
if errorlevel 2 goto SkipDefrag
defrag c:
:SkipDefrag
If you press N within 5 seconds, DEFRAG will not run and CHOICE returns an
ERRORLEVEL value of 2. If you do not press N within 5 seconds, or if you
choose Y, DEFRAG is run on drive C.
Using CHOICE in a batch program
The following batch program demonstrates using the CHOICE option to select
one of three programs: MS-DOS Editor, Microsoft Anti-Virus, or Microsoft
Backup.
Notice that the IF ERRORLEVEL statements are listed in decreasing order.
MS-DOS will consider the IF statement true if the ERRORLEVEL parameter
returned by CHOICE is greater than or equal to the parameter specified in
the IF command.
@echo off
cls
echo.
echo A Microsoft Editor
echo B Microsoft Anti-Virus
echo C Microsoft Backup
echo.
choice /c:abc Choose an option
if errorlevel 3 goto MSBackup
if errorlevel 2 goto Msav
if errorlevel 1 goto Edit
:Edit
edit
goto End
:Msav
msav
goto End
:Msbackup
msbackup
goto End
:End
============================================================================
ras...@highfiber.com
<mjg...@atl.mediaone.net> wrote:
>That;s what the /? is for..........
Er, anything listed in the /? syntax display is by definition not
undocumented.
Here are a few MUFs, just off the top of my head. Some of these
may not exist in Windows 95, or under non-Microsoft versions of
DOS.
DIR,
That's DIR followed by a comma. Lists all files and subdirectories
in the current directory, regardless of attributes. Basically, it's a
handy shorter alternative to DIR /A
ATTRIB,
Again, the command is followed by a comma. Removes all attributes
from all files in the current directory, like ATTRIB *.* -S -H -R -A
COMMAND /Z
This switch only exists in Windows 9x COMMAND.COM, though I
think 4DOS also has it. Displays the exit code (errorlevel) when
each program terminates.
LFNFOR
Another Win95 feature. Controls whether the FOR command returns
short or long filenames.
VER /R
Gives a little more information.
TRUENAME foo
Displays the absolute pathname for file "foo". Resolves . and ..
entries, implicit directories, JOIN and SUBST drives, network
assignments, etc. Note that the file "foo" does not actually have
to exist. This completely undocumented command has some very
non-obvious features, like displaying names of character devices in
a different format. A good example of the /? display not telling the
whole story, by the way.
FDISK /MBR
Rewrites the Master Boot Record on the primary hard drive. This
can be used to overwrite and destory some boot-sector viruses,
and to remove boot loaders like LILO. However, for some viruses
such as Monkey, this command can cause Massive Bad Results.
A less dangerous undocumented switch is /STATUS.
One oddball undocumented feature of the DIR command is the
way it handles files with a date stamp of 0000h. They are shown
with no date or time:
Volume in drive C is blissful
Volume Serial Number is 255E-AF74
Directory of C:\Q
. <DIR> 01-28-99 7:13p
.. <DIR> 01-28-99 7:13p
WP BAT 73 04-05-98 9:40a
HUNT BAT 29
UNZ BAT 677 02-10-96 1:00p
5 file(s) 779 bytes
357,408,768 bytes free
>Dav1936531 wrote in message
><19990126234957...@ng-fp1.aol.com>...
>>>From: sma...@banet.net (Stephen S.)
>>>Date: 1/26/99 9:05 PM Eastern Standard Time
>>>Message-id: <36b0744b...@news1.banet.net>
>>>
>>>A while back (this is like two of three years now) I had a paper that
>>>dealt with undocumented DOS commands. I now have a class that I would
>>>like to share this with but I can't find my old copy nor can I find
information
>>>about this on the internet. Of course MS is no help either!?
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Larry Weiss
> DIR,
> That's DIR followed by a comma. Lists all files and subdirectories
> in the current directory, regardless of attributes. Basically, it's a
> handy shorter alternative to DIR /A
>
Didn't work on files with Hidden attribute. Wasn't equivalent at all
to DIR /A.
Larry Weiss
> ATTRIB,
> Again, the command is followed by a comma. Removes all attributes
> from all files in the current directory, like ATTRIB *.* -S -H -R -A
>
Nope. Didn't do it. Wasn't equivalent at all to
Larry Weiss
> LFNFOR
> Another Win95 feature. Controls whether the FOR command returns
> short or long filenames.
>
What do you mean that this command is undocumented?
In other words, where is the doc that would document it if it
were documented?
- Larry Weiss
Laurence Soucy
What does it mean?
Laurence
ras...@highfiber.com wrote:
>
> On Wed, 27 Jan 1999 20:24, "Michael J. Gregg"
> <mjg...@atl.mediaone.net> wrote:
>
> >That;s what the /? is for..........
>
> Er, anything listed in the /? syntax display is by definition not
> undocumented.
>
> Here are a few MUFs, just off the top of my head. Some of these
> may not exist in Windows 95, or under non-Microsoft versions of
> DOS.
>
> DIR,
>
> That's DIR followed by a comma. Lists all files and subdirectories
> in the current directory, regardless of attributes. Basically, it's a
> handy shorter alternative to DIR /A
>
> ATTRIB,
>
> Again, the command is followed by a comma. Removes all attributes
> from all files in the current directory, like ATTRIB *.* -S -H -R -A
>
> COMMAND /Z
>
> This switch only exists in Windows 9x COMMAND.COM, though I
> think 4DOS also has it. Displays the exit code (errorlevel) when
> each program terminates.
>
> LFNFOR
>
> Another Win95 feature. Controls whether the FOR command returns
> short or long filenames.
>
Laurence Soucy
of 6.22
ATTRIB,
DIR,
Laurence
Larry Weiss wrote:
>
> ras...@highfiber.com wrote:
> > ATTRIB,
> > Again, the command is followed by a comma. Removes all attributes
> > from all files in the current directory, like ATTRIB *.* -S -H -R -A
> >
>
> Nope. Didn't do it. Wasn't equivalent at all to
>
Larry Weiss
> Larry Weiss wrote:
> > ras...@highfiber.com wrote:
> > > ATTRIB,
> > > Again, the command is followed by a comma. Removes all attributes
> > > from all files in the current directory, like ATTRIB *.* -S -H -R -A
> > Nope. Didn't do it. Wasn't equivalent at all to
> > ATTRIB *.* -S -H -R -A
> >
> of 6.22
> ATTRIB,
> DIR,
I should have mentioned it already, but I'm using Windows 95.
Are those behaviors relevant only to 6.22 ?
- Larry Weiss
Larry Weiss
> Larry Weiss <l...@airmail.net> wrote:
> > ras...@highfiber.com wrote:
> > > LFNFOR
> > > Another Win95 feature. Controls whether the FOR command returns
> > > short or long filenames.
> > In other words, where is the doc that would document it if it
> > were documented?
> I have just gleefully reformatted my last remaining Win95 system.
> Yes, there is some limited documentation for Win95 DOS commands,
> including the new XCOPY switches and so forth. It's just not very
> obvious. Look for .TXT files in your \WINDOWS directory. This is
> from memory, and may have errors, but I recall a CONFIG.TXT (listing
> CONFIG.SYS directives,) MSDOSDRV.TXT (arguments for device drivers,)
> and COMMANDS.TXT (command-line utilities.) There's also a section
> on DOS commands in the Windows 95 Resource Kit, which is a .HLP file
> buried somewhere on the Windows 95 CD-ROM. I don't *think* LFNFOR
> is mentioned anywhere in either the text files or the Resource Kit;
> at least that is not how I found out about it. You may prove me
> wrong, though.
>
I just mean that from where I stand here under Windows 95,
LFNFOR is just as well (or poorly) documented as any other
command. I'm still searching for something like the old
HELP command that pulls it all together under one resource.
Thanks for the hints about where to look.
- Larry Weiss
Larry Weiss
> > > Again, the command is followed by a comma. Removes all attributes
> > > from all files in the current directory, like ATTRIB *.* -S -H -R -A
> > Nope. Didn't do it. Wasn't equivalent at all to
> > ATTRIB *.* -S -H -R -A
> IBM DOS 5 through 7, or using my clone ATTRIB. Elementary, Watson.
Guess I'm using the debugged version here under Windows 95. <g>
I suppose there's not something like DIR's DIRCMD environment variable
for ATTRIB to use instead to get the same effect?
- Larry Weiss
Larry Weiss
> Microsoft didn't exactly spread the word about it, but it's not
> undocumented either. You can type LFNFOR/? at a command prompt for a
> very terse explanation of the command.
I finally found one article in MS' Technical Support Online database:
( http://search.microsoft.com/ then register under "Support Online")
"FOR Command Does Not Support Long Filenames in Windows 95"
Last reviewed: October 13, 1995
Article ID: Q138154
So far that's the formal documentation! (terse though it might be...)
MS is definitely not spending their billions on supporting MSDOS...
I wonder how much longer they will offer the "MSDOS Prompt" applet?
- Larry Weiss
DONALD G. DAVIS
>What kind of date is 0000h?
>What does it mean?
He was talking about what happens if null bytes are entered in the
date field in a file's directory entry on disk. DIR on such a file yields
a blank date and time in the display. Conversely, if you enter improperly
high values in the date/time fields, DIR can show months as high as 15 and
minutes as high as 63.
--Donald Davis
ras...@highfiber.com
<285CFEC00E301851.5BC7F416...@library-proxy.airnews.net
>, Larry Weiss <l...@airmail.net> wrote:
> ras...@highfiber.com wrote:
> > LFNFOR
> > Another Win95 feature. Controls whether the FOR command returns
> > short or long filenames.
> What do you mean that this command is undocumented?
>
> In other words, where is the doc that would document it if it
> were documented?
An excellent question. I'm unable to give an exact answer, because
I have just gleefully reformatted my last remaining Win95 system.
Yes, there is some limited documentation for Win95 DOS commands,
including the new XCOPY switches and so forth. It's just not very
obvious. Look for .TXT files in your \WINDOWS directory. This is
from memory, and may have errors, but I recall a CONFIG.TXT (listing
CONFIG.SYS directives,) MSDOSDRV.TXT (arguments for device drivers,)
and COMMANDS.TXT (command-line utilities.) There's also a section
on DOS commands in the Windows 95 Resource Kit, which is a .HLP file
buried somewhere on the Windows 95 CD-ROM. I don't *think* LFNFOR
is mentioned anywhere in either the text files or the Resource Kit;
at least that is not how I found out about it. You may prove me
wrong, though.
ras...@highfiber.com
<D9B6888354E1BAF6.2E281CBF...@library-proxy.airnews.net
>, Larry Weiss <l...@airmail.net> wrote:
> ras...@highfiber.com wrote:
> > ATTRIB,
> > Again, the command is followed by a comma. Removes all attributes
> > from all files in the current directory, like ATTRIB *.* -S -H -R -A
> Nope. Didn't do it. Wasn't equivalent at all to
>
> ATTRIB *.* -S -H -R -A
From which I speedily deduce that you are not running MS-DOS 5 or 6.x,
IBM DOS 5 through 7, or using my clone ATTRIB. Elementary, Watson.
ras...@highfiber.com
I just mean a date value of zero. I write it as four hex digits to show
that this is a word value (two bytes) -- which is what MS-DOS allots for
storing the date stamp.
A value of zero would translate as 0-0-1980. MS-DOS will not normally
assign this value to a file's date stamp, but many "touch" utilities can.
The directory listing below is actual redirected output from the DOS 6.22
DIR command, after touching the file HUNT.BAT with the 0-0-1980 date. I
didn't change the file's *time* stamp -- if the date is set to zero, DIR
will suppress both the date and time.
> > One oddball undocumented feature of the DIR command is the
> > way it handles files with a date stamp of 0000h. They are shown
> > with no date or time:
> >
> > Volume in drive C is blissful
> > Volume Serial Number is 255E-AF74
> > Directory of C:\Q
> >
> > . <DIR> 01-28-99 7:13p
> > .. <DIR> 01-28-99 7:13p
> > WP BAT 73 04-05-98 9:40a
> > HUNT BAT 29
> > UNZ BAT 677 02-10-96 1:00p
> > 5 file(s) 779 bytes
> > 357,408,768 bytes free
Walter Zackery
Al Aab
simtel/msdos
c/
undoc-cl.swi 3045 870709 UNDOCUMENTED c compiler switches (ms-c 4.0)
info/
dos400un 2211 881110 UNDOCUMENTED commands in pc-dos 4.00 and 4.01
drivparm 2358 880528 UNDOCUMENTED config.sys 'drivparm' parameter
muf17 66465 960407 microsoft's UNDOCUMENTED features, vol 1, no 7
undocdos 17326 910401 errata for the book UNDOCUMENTED dos - 910309
sysutl/
undoc2eh 2279 890108 demo of UNDOCUMENTED interrupt service 2eh
--
=-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
al aab, seders moderator sed u soon
it is not zat we do not see the s o l u t i o n
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
ras...@highfiber.com
> simtel/msdos
>
> info/
>muf17 66465 960407 microsoft's UNDOCUMENTED features, vol 1, no 7
Aha! This is the "Microsoft Undocumented Features" list from the
FidoNet BatPower echo. Detailed discussion of all kinds of flakey
little Microsoft features, and their practical application to batch
files. (How can you tell whether AUTOEXEC.BAT is being run
automatically at system boot, or restarted by the user typing
AUTOEXEC at the prompt? Easy -- check the contents of the %0
replaceable parameter!)
I've been trying to find a URL for this file -- it's very appropriate
to this thread -- but had no luck. Thanks for the pointer, Al.
ras...@highfiber.com
<9F8E111B016C772F.5D64577A...@library-proxy.airnews.net
>, Larry Weiss <l...@airmail.net> wrote:
>
> (Re: DIR, and ATTRIB, under Bag95)
>
> Guess I'm using the debugged version here under Windows 95. <g>
Correct me if I'm wrong, but I think the comma is actually a legal
character in long filenames. What happens if you do, say:
REM > ","
> I suppose there's not something like DIR's DIRCMD environment variable
> for ATTRIB to use instead to get the same effect?
Well, you can use the documented parameters <g> A lot more typing,
but accomplishes the same thing.
ras...@highfiber.com
<D7600F9B2906DD98.F27D3A5B...@library-proxy.airnews.net
>, Larry Weiss <l...@airmail.net> wrote:
>
> I just mean that from where I stand here under Windows 95,
> LFNFOR is just as well (or poorly) documented as any other
> command. I'm still searching for something like the old
> HELP command that pulls it all together under one resource.
I must say that documenting MS-DOS commands in a Windows help
file (which you can't read from DOS) is a decidedly awkward
method.
The Windows 98 CD-ROM still includes the old DOS HELP system,
which *still* has not been updated. Fire it up, and the first
help topic listed is "What's New In MS-DOS 6.22?" Answer: Not
much, Bill!
> Thanks for the hints about where to look.
>
> - Larry Weiss
Larry Weiss
> On Sat, 30 Jan 1999 09:36, af...@torfree.net (Al Aab) wrote:
> > simtel/msdos
> > info/
> >muf17 66465 960407 microsoft's UNDOCUMENTED features, vol 1, no 7
>
> Aha! This is the "Microsoft Undocumented Features" list from the
> FidoNet BatPower echo. Detailed discussion of all kinds of flakey
> little Microsoft features, and their practical application to batch
> files. (How can you tell whether AUTOEXEC.BAT is being run
> automatically at system boot, or restarted by the user typing
> AUTOEXEC at the prompt? Easy -- check the contents of the %0
> replaceable parameter!)
> I've been trying to find a URL for this file -- it's very appropriate
> to this thread -- but had no luck. Thanks for the pointer, Al.
>
Do you have that handy in the form of a URL?
- Larry Weiss (an old Fidonet BATPOWER echo participant)
Ralf Buschmann
Nachricht <news:78rado$hmk$1...@nnrp1.dejanews.com>:
>FDISK /MBR
>
>Rewrites the Master Boot Record on the primary hard drive.
FDISK x /CMBR
Rewrites MBR on hard drive x (x in the range of 1-4, I believe).
FDISK /X
Disables use of INT13 extensions. Limits accessible space on drive to 8
gigs. (Win95/98 only).
FDISK x [/pri:ps] [/prio:ps] [/ext:es] [/log:ls] [/logo:ls] [/fprmt]
x - hard drive number
/pri:ps - creates primary partition of ps megs
/prio:ps - creates FAT16 primary partition of ps megs (Win95b/98
only)
/ext:es - creates extended partition of es megs
/log:ls - creates logical drive of ls megs in extended partition
/logo:ls - creates FAT16 logical drive of ls megs in extended
partition (Win95b/98 only)
/fprmt - creates FAT32 partitions unconditionally, even on
drives smaller than 510 megs.
* /pri: (/prio:), /ext: and /log: (/logo:) may be used simultaneously,
but only one /log: (/logo:) switch is accepted at time.
* /pri:ps and /log:ls create FAT32 partitions/logical drives if ps/ls is
>510 (Win95b/Win98).
* switches do not destroy/overwrite any existing partitioning.
* if you use a number for ps, es or ls that is larger than the free
space on the drive, FDISK just uses all the remaining free space.
* /fprmt cannot be combined with any of the other switches.
* /log: (/logo:) not working on hard drives >8 gigs.
Did you know: you can automate FDISK by scripts containing all the user
input line-per-line. Syntax:
fdisk <script.txt
Hints: For ESC key, press Ctrl-P in MS-DOS EDIT, then type Alt-27 on
your num keypad. No line breaks after ESC!
Greetings,
Ralf.
--
________________________________________________________________________
Windows 9x Disaster Recovery & Cloning | Windows 95 Tricks & Software
http://www.backmagic.de http://win95.winware.org
Michael J. Gregg
Larry Weiss <l...@airmail.net> wrote in message
news:313D095D5D2933AB.D29FFE5E...@library-proxy.airnew
s.net...
ras...@highfiber.com
<E0913C8121C7F135.AEC1DBBB...@library-proxy.airnews.net
>, Larry Weiss <l...@airmail.net> wrote:
Try ftp://ftp.simtel.net/pub/simtelnet/msdos/info/muf17.zip
Simtel has numerous mirrors, too. There's one at cdrom.com, I believe.
Gary S. Patrick
Stephen S. wrote in message <36b0744b...@news1.banet.net>...
:A while back (this is like two of three years now) I had a paper that
:dealt with undocumented DOS commands <snip>
This may be the file you were asking for; pulled this one off fidonet
some years ago.
Geepers
(Gary)
***************************************************************
The
Fabulous
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List
(MicroSoft's Undocumented Features)
Volume 1 Number 6
============================================================================
===
1) TRUENAME
Internal DOS 5.0 command. Canonicalize a filename or path (using
DOS interrupt 21h, function 60) prints the actual directory.
SYNTAX
TRUENAME filename prints the complete path to file
TRUENAME directory prints the complete path to directory
Note: If the path is in a network, it starts with a \\machine-name
Michael Larsson
TRUENAME is analogous to the "whence" command in the UNIX Korn
shell. It returns the real fully qualified pathname for a command.
TRUENAME is useful in networks, where a physical drive may be mapped
to a logical volume, and the user needs to know the physical location
of the file. It ignores the DOS SUBST, and JOIN commands, or network
MAPped drives.
It is an undocumented MS/DOS feature, but is documented in 4DOS as
follows:
SYNTAX (Internal DOS 5.0 / 4DOS)
TRUENAME [d:][path]filename
PURPOSE
Returns a fully qualified filename.
COMMENTS
TRUENAME will see "through" JOIN and SUBST commands, and requires
MS-DOS 3.0 or above.
EXAMPLE
The following command uses TRUENAME to get the true pathname for a
file:
c:\> subst d: c:\util\test
c:\> truename d:\test.exe
c:\util\test\test.exe
Dennis McCunney
TRUENAME : will reveal the full name drive and path of the filename.
If you specify a wildcard ('*') in the filename, it will expand
the filename to use question marks instead. If the path includes
the ..\ sequence, TRUENAME will examine the directory structure and
calculate the path. Stranger still, the line:
TRUENAME \CRONK\FLIBBET\..\ART
produces the response:
C:\CRONK\ART
even if the directories \CRONK\FLIBBET and the file ART don't exist!
Don't expect this command to work across networks.
PC Magazine #212 Pg. 48-49
Forwarded by:
Rodney Atkins
============================================================================
===
2) FDISK /STATUS ?
Prints a screen just like using option 4 of fdisk "Partition
information", but includes extended partition information.
Nice if you want to get an overview without fear of pressing
the wrong keys.
Armin Hanisch
Doesn't work in Ver 3.30.
Mitch Ames
FDISK /MBR
MS-DOS 5.0 FDISK has an undocumented parameter, /MBR, that causes it
to write the master boot record to the hard disk without altering the
partition table information. While this feature is not documented, it
can be told to customers on a need-to-know basis.
What is the MBR?
At the end of the ROM BIOS bootstrap routine, the BIOS will read and
execute the first physical sector of the first floppy or hard drive on
the system. This first sector of the hard disk is called the master
boot record, or sometimes the partition table or master boot block. At
the beginning of this sector of the hard disk is a small program. At
the end of this sector is where the partition information, or
partition table, is stored. This program uses the partition
information to determine which partition is bootable (usually the
first primary DOS partition) and attempts to boot from it.
This program is what is written to the disk by FDISK /MBR and is
usually called the master boot record. During normal operation,
FDISK only writes this program to the disk if there is no master
boot record.
Why is the MBR changed during Setup?
During installation of Microsoft MS-DOS 5 Upgrade, Setup will replace
the master boot record on the hard disk with code to display the
message:
The MS-DOS 5.0 Setup was not completed.
Insert the UNINSTALL #1 diskette in drive A.
Press the ENTER key to continue.
This message should be erased and the master boot code rewritten
before Setup is completed. If a problem occurs during Setup and you
return to the previous MS-DOS, UNINSTAL should also remove this
message. However, should Setup or UNINSTAL fail to remove this
message, or should the master boot record become corrupted, a new
master boot record can be written to the disk using the following
command:
C:\>fdisk /mbr
Warning: Writing the master boot record to the hard disk in this
manner can make certain hard disks unusable. IE: those partitioned
with SpeedStor, or Microhouse's DrivePro program. It can also cause
problems for some dual-boot programs, or for disks with more than 4
partitions. Specific information is below.
WARNINGS:
This option should not be used if:
- the disk was partitioned using Storage Dimensions' SpeedStor
utility with its /Bootall option
- the disk was partitioned using MicroHouse's DrivePro program AND
the drive was NOT setup using a standard CMOS value.
- more than 4 partitions exist
- certain dual-boot programs are in use
Storage Dimensions' SpeedStor utility using the /Bootall option
redefines the drive's physical parameters (cylinder, head, sector).
/BOOTALL stores information on how the drive has been changed in an
area of the master boot record that MS-DOS does not use. FDISK /MBR
will erase that information, making the disk unusable.
MicroHouse's DrivePro program functions similarly to SpeedStor above,
and has the same boot record vulnerability. MicroHouse identifies their
boot program at boot-up by a small MICROHOUSE logo near the left side of
the screen about two-thirds down, at power on. If you see this logo,
do NOT use FDISK /MBR, or the drive will become unusable.
Some older OEM versions of MS-DOS and some third-party partitioning
utilities can create more than 4 partitions. Additional partition
information is commonly stored information on partitions in an area
that FDISK /MBR will overwrite.
Some dual-boot programs have a special MBR that asks the user which
operating system they want on bootup. FDISK /MBR erases this program.
Dual-boot systems that boot whichever partition is marked Active are
not affected by FDISK /MBR.
Edited: MicroSoft Publication
forwarded by Don Dean
editing suggestions made by
Matt Mc_Carthy (info re:
MicroHouse's DrivePro)
If you have a Boot Sector Virus, just boot from a known "clean"
floppy disk (which has the System files and FDISK on it - IE:
your "disaster recovery disk") and run FDISK /MBR. Bye, Bye Virus!
Gary Cooper
Make sure it's write protected ..
Jasen Betts
[Begin quote]
One of the FDISK functions, updating the Master Boot Record (MBR),
does not appear on any of the FDISK menus. The Master Boot Record is
located at the beginning of your primary fixed disk. It is composed of
two parts -- the master boot code and the partition table. The master
boot code is a short program that determines which operating system
will start the computer, then transfers control to that operating
system.
The partition table contains information about the partitions located on
the fixed disk.
The Master Boot Record may need to be updated when:
* An operating system other than MS-DOS is on the fixed disk.
Some operating systems replace the master boot code with their
own program, which may not allow MS-DOS to start the system,
even if the partitions are valid DOS partitions. If this condition
exists, updating the Master Boot Record will replace only the master
boot code.
* The information at the beginning of the fixed disk has been
overwritten. The partition information is destroyed and the fixed
disk will no longer start any operating system. If this condition
exists, updating the Master Boot Record will replace both the master
boot code and the partition table. However, the partition table will
not have any defined partitions.
If you cannot get your system to start MS-DOS from the fixed disk and
you are sure the initialization process was performed correctly, you
may need to update the Master Boot Record. To do this, enter the
following command:
FDISK /MBR
FDISK does not display any menus or messages while it is updating the
Master Boot Record. When the procedure is complete, the MS-DOS
prompt is displayed.
If you are unable to start MS-DOS from the fixed disk after updating
the Master Boot Record, you may need to partition and format your fixed
disk. If you still cannot use the fixed disk to start MS-DOS, contact
your Authorized COMPAQ Computer Dealer for further assistance.
[End quote]
Compaq DOS 4.01 Manual
Submitted by
Paul Maserang
If the situation at hand involved a trashed partition table. This
regenerates the partition table, but does NOT restore the user
partition information in it. Therefore, after using FDISK /MBR, you
must still use FDISK without the /MBR switch to re-enter the partition
information before you can do anything else. If the newly entered
partition information is identical to that which existed there prior
to the partition table being trashed, and nothing else has been damaged,
there should be no need to reformat the drive, because the boot sector,
FATs, directories, and data should still be undisturbed. If the boot
sector or either of the two hidden system files (IBMBIO.COM/IBMDOS.COM
or IO.SYS/MSDOS.SYS) are damaged, the SYS command can be used to restore
them without losing anything else.
Paul Maserang
Paul, I work _only_ with the Microsoft versions, and have not had the
same experience. The /MBR parameter _only_ rewrites the MBR. It does
not affect the partition information. I use it daily on various
machines and have not lost one byte of data.
Matt Mc_carthy
I guess you didn't know that "Master Boot Record" and "Partition Table"
refer to the same thing. What you're talking about is the master boot
CODE, the executable code that accompanies the partition table and is
located on the same physical sector (0).
Here's what I find in the first few bytes of my physical sector 0
(unassembled with DEBUG after copying the sector to a file):
2BB7:0100 33C0 XOR AX,AX
2BB7:0102 FA CLI
2BB7:0103 BED0 MOV SS,AX
2BB7:0105 BC007C MOV SP,7C00
2BB7:0108 BEC0 MOV ES,AX
2BB7:010A BED8 MOV DS,AX
2BB7:010C FB STI
2BB7:010D 8BF4 MOV SI,SP
2BB7:010F BF0006 MOV DI,0600
2BB7:0112 B90002 MOV CX,0200
2BB7:0115 FC CLD
2BB7:0116 F3 REPZ
2BB7:0117 A4 MOVSB
2BB7:0118 EA1D060000 JMP 0000:061D
I also find the following text in the first half of the sector:
Missing operating system.Error loading operating system.Invalid
partition table.Author - Siegmar Schmidt
I have only one partition on my C: drive, and its information is in
the last of four possible positions in the partition table. The first
significant byte (non-zero) is at offset 01EEh in physical sector 0.
The rest, from offset 00EDh to 01EDh is nothing but 00h.
So it would appear that everything from offset 0000h to 00ECh is the
Master Boot CODE, and everything from 00EDh to the end of the sector
(01FFh) is the Master Boot RECORD (aka partition table). More likely,
the partition table probably begins at offset 0100h, and takes up the
last 256 of the 512 bytes available in the sector.
Beginning with the first significant byte of my partition table (at
offset 01EEh), this is what mine shows:
80 01 01 04 03 91 65 11 00 00 00 07 A3 00 00 55 AA
^^
This first byte, I think, is the drive on which this partition
is located, and the next byte might indicate that this is the
first (primary) partition (in my case, the ONLY partition for
this drive).
Now, according to my manual, FDISK /MBR can either re-write only
the Master Boot CODE when necessary; or it can re-write both the
Master Boot Code AND the Master Boot RECORD, if it determines that
the partition table has been corrupted.
If it does re-write both, then you do have to use FDISK without
the /MBR switch after using it with the switch, because the
re-written partition table has no defined partitions until you do.
But when you use the /MBR switch, it produces no screen output
(at least not on the version I'm using), so you don't know whether
it did both or just the code. So you should still check to see that
you have a valid partition by using FDISK without the /MBR switch
afterwards.
Paul Maserang
============================================================================
===
3) SHELL=C:\COMMAND.COM /E:1024 /F /P
The /F in your Config.sys SHELL= statement is another undocumented
feature.
It forces a "Fail" response to the "Abort, Retry, Fail" prompt issued
by the DOS critical error handler.
Dennis McCunney
The /F switch on the SHELL command in CONFIG.SYS will not work in
a DESQview environment. The only thing I have found that will is a
program called FATAL.COM.
Bruce Bowman
COMMAND /F
Makes all those annoying "Abort, Retry, Ignore, Fail?"
disk error messages default to "Fail".
Erik Ratcliffe
For DOS 3.30 (somebody might care to check these for other versions):
COMMAND /P
Docs say that this doesn't allow you to exit back to the
previous shell (ie /Permanent), but /P also forces
\autoexec.bat to be run on secondary shells.
COMMAND /D
(When used with a primary shell, or secondary with /P)
prevents execution of \autoexec.bat
Mitch Ames
I just checked, and these also both apply to DOS 5.00
Mitch Ames
============================================================================
===
4) VER/R
Yields extended information about the OS Version. IE:
MS-DOS Version 5.00
Revision A
DOS is in HMA
Billy Gilbreath
Doesn't work with DOS 3.30
Mitch Ames
============================================================================
===
5) ECHO OFF from the command line erases the prompt and leaves
just a cursor on the screen.
ECHO ON from the command line restores the prompt.
This works with all version of DOS (tested so far!).
Michael Larsson
One of the most frequently asked questions in the BatPower echo
is "How do I ECHO a blank line?" The most common answer is "ECHO."
However, I have captured a few posts which expand on the
possible answers to this request:
Editor's Note
ECHO"
Paul Welsh
just about any white space character will work.
Alan Newbery
I just found out myself that any delimiter will work here
(ECHO. ECHO" ECHO, ECHO: ECHO; ECHO[ ECHO] etc.). Apparently
it's just the way that the command handles the delimiter and
has been available from way back. Microsoft just began
mentioning it in the documentation recently, though, and their
examples use a period.
John Whitfield
============================================================================
===
6) FORMAT
FORMAT /H
In DOS 3.30 (I don't know about other versions), FORMAT /H
will cause the format to begin immediately after pressing Y
in response to "Format another?", rather than displaying
"Place disk to be formatted in drive A: and press Enter" on
a second and subsequent disks.
Mitch Ames
On 5.0 it comes back as "invalid switch".
John Mudge
FORMAT A: /AUTOTEST
The autotest parameter will allow format to proceed, checking
existing format (unless the /u parameter is also present) and
proceeding with the format.
All this will take place with no delay and no waiting for user
input. It will also end without pausing. It will not ask for
a volume label or whether to format another diskette.
WARNING! This procedure will also work on hard drives! Be very
cautious if you plan to use this feature.
Wayne Woodman
Problem is that it won't take any other switches like /U, /S or
/Q which is a bit of a shame really.
Peter Lovell
With Dos 5 it certainly takes /u and /s as I have used it, in
fact I think /u is required if the disk is not pre-formatted as
the drive hangs up otherwise.
I would agree about /q though, this does not work and gives the
error message you quote.
Terry Kreft
FORMAT/U is not available in DOS 3.30
Mitch Ames
FORMAT C: /BACKUP
This week I've read some articles in Dutch computer magazines about
MUF's which are very interesting (if you don't already know about
them).
I already knew the FORMAT option /AUTOTEST, but new to me was the
/BACKUP option.
EXAMPLE: FORMAT A: /BACKUP
It seems to work exactly like /AUTOTEST, but it DOES ask for a
volume label.
Willem Van.den.broek
FORMAT/SELECT
is like DOS-Mirror ... for safety-fanatics only
FORMAT/SELECT/U
makes disks unreadable (remember the U)
Reinhard Kujawa
Info from The German magazine PC PRAXIS
FORMAT A: /SPACE
On IBM DOS v6.01 the command:
FORMAT A: /SPACE
puts a 12288 byte file named MIRROR.FIL on the disk ...
So, the command:
FORMAT A: /U /SPACE
just ruins the durn diskette! A subsequent "DIR A:" gives you a:
General failure reading drive A
Abort, Retry, Fail
Vernon Frazee
============================================================================
===
7) DRIVPARM /c
Syntax: DRIVPARM /d:number [/c] [/f:factor] [/h:heads] [/i] [/n]
[/s:sectors] [/t:tracks]
/d:n refers to the drive NUMBER (0=A:, 1=B:, 2=C:, etc...) of the
drive
whose parameters you are changing (in your case, it would be 2
for
B:).
/c is the switch I was referring to for change line support. IF YOU
INCLUDE /c, YOU ARE TELLING DOS THAT YOUR COMPUTER *CAN* TELL
WHETHER THE DRIVE DOOR HAS BEEN OPENED SINCE THE LAST ACCESS.
/i specifies an electronically-compatible 3.5 inch floppy
disk-drive.
You should use it if your computer's ROM BIOS does NOT support
3.5
floppy diskette drives.
/n specifies a NON-removable block device
The other parms are similar to DRIVER.SYS
IBM Technical Publication Information
forwarded by Andrew Barnhardt
The '/C' switch doesn't actually check to see if the drive -door-
has been opened or not, but it does make another check to see if
the disk in there now is different from the one when the drive was
last accessed. I have to use that switch with my 5 1/4 floppy
because it's an older drive working with a new motherboard (at
least that's the explanation I've heard).
Andrew Barnhardt
Does DRIVPARM return an errorlevel, or give a warning message?
Gary Cooper
No, not that I'm aware of. You insert the drivparm command in
your CONFIG.SYS file. Just DRIVPARM=xx xx ...
Andrew Barnhardt
============================================================================
===
8) IF EXIST
IE: IF EXIST EMMXXXX0 GOTO APPLICATION
This is a handy quirk of DOS - installable drivers are seen as files
in all directories. You can use the if exist test to either test for
the existence of a directory, with "if exist <dirname>\nul", (which
fails if the directory does not exist because the nul device is not
found,) or to test whether a driver is loaded.
Caveats: you need to know the name of the directory or the driver
whose existance you are testing, and this is MS/DOS specific - it
doesn't work on network drives, and may not work under DR-DOS.
Gary Marden
This works definitely under DRDOS:
DR DOS Version 6.0
Copyright (c) 1976,1982,1988,1990,1991 Digital Research Inc.
Alle Rechte vorbehalten.
C:\>if exist emmxxxx0 echo ja
ja
Wolfram Serber
Where did you learn the "EMMXXXX0" name from?
Instead of typing MEM /C, type MEM /D for the "debug" listing.
That should give the names you're looking for.
Erik Ratcliffe
The trouble is, EXISTS returns TRUE for COM3/4 and LPT2/3 even
though the hardware does not exist.
Rudy Lacchin
============================================================================
===
9) SWITCHES
SWITCHES=/W
Enables you to have your WINA20 file anywhere on your boot
drive. Without this you have to have it in the root directory.
Erik Ratcliffe
You should also mention that this one should not be used with
Windows 3.1. I've noticed a lot of people who do, and it wastes
around 120K of UMBs.
George Hannah
This is documented in DOS 6.0
Richard Pade
SWITCHES=/F
Do you know that there is a rarely known switch called /F?
If you put this line:
SWITCHES=/F
as the first line in your CONFIG.SYS, MS-DOS would not delay 2
seconds, but immediately start processing your CONFIG.SYS. This
trick has no other effects (AFAIK), but those who DO know better,
correct me if I'm wrong!
Samuel Tan Yi Hsuen
But where would you put the switch, it's not like you load a device
driver that early in boot up do you?
RF? Beats me. I think it goes in the SHELL= statement. Just don't
RF? remember what character you use. I saw it mentioned in the
RF? Tech conference /K maybe?
No, it's SWITCHES=/F, right?
Paul Senechko
Actually, its both:
/W allows you to move the WINA20.386 file
/K makes your AT Keyboard act like a XT
/F Disables the wait
/N Disables F5/F8 exiting
and to use any just put the command SWITCHES= and the parameters
on the first line of your config.sys (Can go on other lines, but for
the /F and /N you need it at the first line....), also the Switches
command IS compatible w/ DOS 5, but only using the /W & /K options
John Guillory
============================================================================
===
10) FOR IN DO
for %%z in (test1 test2 test3) do goto %%z
goto end
:test1
echo test1
:test2
echo test2
:test3
echo test3
:end
When I posted this explaining the traps and pitfalls
of FOR IN DO, something got lost. GOTO commands in FOR IN DO
statements do not work correctly / as expected. This fragment
will work in 4DOS, but not with COMMAND.COM. You've seen
what happens when running under COMMAND.COM already. 4DOS
will display test1 test2 test3.
So, that's what I was trying to explain: that GOTO's don't work
right, and that IF's will break FOR IN DO's.
Bill George
============================================================================
===
11) FOR %%V IN /SOMETHING
... quoting Dirk Treusch to All ...
How can a batch file (without 4DOS) determine from which drive it has
been started?
Example: C:\> a:test.bat
Now my batch should be able to find out that it is located on drive A:
(not the path - only drive!).
Mitch Ames responds:
The variable %0 contains the name of the batch file
_as_it_was_typed_at_the_command_line. If you call the batch file as
A:TEST.BAT, %0 will be "A:TEST.BAT". If you have the directory on
your path, and simply type TEST, then %0 will be "TEST". The drive,
path and extension will only appear in %0 if you enter them in the
command used to call the batch file (either typed at the command
line, or called from another batch file).
So you _must_ specify the drive as part of the batch filename for
this to work. To extract the drive only, use STRINGS, or similar (I
don't have a copy, so don't ask me to post it). Alternatively use
the undocumented FOR %%V in /SOMETHING command, eg:
set drive=
for %%v in (/%0) do call test2 %%v
echo Calling drive is %drive%
where TEST2.BAT is:
if not '%drive%'=='' set drive=%1:
Disclaimer - I haven't tested this. Debugging is up to you.
(You can, of course, fit this into a single recursive batch file -
but that's left as an exercise for the student.)
FOR %%V IN (/SOMETHING) DO WHATEVER will do WHATEVER twice - the
first time with %%V set to the first character in SOMETHING ("S"),
the second time with all the remaining characters in SOMETHING
("OMETHING"). If SOMETHING is only a single character, WHATEVER will
only be called once, with that character in %%V. If the single
character is a wildcard (? or *) that wild card will _not_ be
expanded to a set of filenames. (The main purpose of this feature is
apparently to allow inclusion of the literal characters "?" and "*"
without them being expanded.)
This works in DOS 3.30 and 5 - I don't know about other versions.
Mitch Ames
============================================================================
===
12) LEADING SLASH WITH FOR IN DO LOOP
In the FOR statement in the INIT and COUNT routines below the
parameters in the () show a leading "/". This seems to separate
the first digit of the environmental variable used within the
brackets (). Am I correct? Is this documented anywhere?
:================= INIT =================
set &=%4&|set n$=%4|set m$=%3|set #=%2|set !=%0
if not '%m$%'=='0' for %%a in (/%m$%z) do if '%%a'=='0' set @=0
%!%
:================= COUNT ================
if '%&%'=='&' goto PROCESS
for %%a in (/%&%) do set &=%%a
Peter Joynson
I have read some articles about this in PC Computing & PC Magazine.
I don't believe it is documented anywhere but you're right, it strips
off the first character of whatever string is passed. I will try to
find one of the articles that explains it better if you need it.
Robert Hupf
Correct. I believe it is not documented (up to DOS 5 anyway) by MS,
but I have read from other sources that the leading / will split an
item into the first character and everything else. Eg:
for %%n in (/hello there) do echo %%n
will display "h", "ello" and "there". "There" is not split because
it is a separate item, delimited by the space. If used with an item
including wildcard (? or *) characters the item will not be expanded
to the files which match it, thus allowing inclusion of those
characters in the set. Eg:
for %%n in (/? /*.bat hello) do echo %%n
will display "?", "*", ".bat", "hello". This apparently is the
original reason for the feature, but it may also be used recursively
to parse a string one character at a time.
Mitch Ames
============================================================================
===
13) ATTRIB
ATTRIB +h dirname
Is there anyway to create a hidden directory on a hard drive?
I've since learned that DOS 5.0 ATTRIB can do the same thing
from the command line: ATTRIB +h dirname.
Gary Smith
ATTRIB ,
attrib ,|echo y|del *.*
It is not really piping the output of attrib to echo. Using the pipe
is one way of stacking multiple commands on one line. All the "attrib
,"
does is reset _ALL_ attributes on _ALL_ files in the current directory.
So if you were to run that from the root of your c: drive you would no
longer have a bootable drive.
Jim Banghart
Worked fine here, took out all the files (system, hidden, read-only),
like a dream with no lock up, using MSDos 5.0
Terry Kreft
I do not recommend this practice. It does attempt to pipe the output
of attrib to echo, and thus writes a file to the directory specified
by the environment variable TEMP. If you try to run this program in
your TEMP directory, you will get a sharing violation. It also
actually slows your program, because it has to write and delete a
useless file (unless you have your TEMP on a ramdisk).
I can't say I see much reason for stacking commands like this -- put
the commands on separate lines. A character is a character, be it a
carriage return or a pipe, and your files will be easier to understand.
Bruce Bowman
============================================================================
===
14) INSTALLHIGH
I think I may have found an undocumented feature for DOS 6....
I wasn't able to find this anywhere in the online help. It's
called INSTALLHIGH= and amazingly enough it works just like
INSTALL= but loads the file high!
The only drawback to this is: Memmaker will not go through and
add switches for that particular line during the "optimizing
process". It just takes it as it is currently. But then again
INSTALL= is ignored too!
Example:
DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\EMM386.EXE NOEMS HIGHSCAN WIN=F500-F7FF WIN=F200-F4FF
dos=HIGH
dos=UMB
installhigh=c:\dos\share.exe
Robin Francis
MUF reported in the magazine C'T: You can use the DOS 6.0 command
"installhigh" in config.sys to load TSR programs into UMA. A 48 byte
environment will be added for every program. If you use it you don't
need the "loadhigh" in autoexec.bat any more.
But Memmaker can't handle installhigh!
Thomas Erbe
Further to Robins explanation, INSTALLHIGH cannot be directed to a
specific UMB area and thus defaults to largest currently available.
Like INSTALL it is processed (about) last of C.SYS lines and causes
more consumed RAM overhead than calling TSR from A.BAT or later.
Richard Pade
There is an undocumented CONFIG.SYS command called INSTALLHIGH. It
is similar to INSTALL except that it will load the TSR into an UMB.
It is available under DOS 6. However, it does not support the
/L and /S switches that DEVICEHIGH and LOADHIGH support.
Tom Dyas
Then it is useless, isn't it? It has less than the capabilities of
LOADHIGH and DEVICEHIGH but load the same TSRs that they load ... no
wonder it is an undocumented command.
Wayne Moses
Just wondering, does INSTALLHIGH work with Microsoft DOS 5? It
would also be nice to know why it is undocumented. It doesn't do
anything major! Microsoft gains nothing by keeping it undocumented.
Loading TSR's from CONFIG.SYS is better because an environment is
not allocated for the TSR. A very small amount of memory is
conserved, but it is still conserved.
Tom Dyas
============================================================================
===
15) : (command)
DOS uses a leading : to indicate a label. If the next character
following the : is a space or other non-alphanumeric char, DOS
will decide it's an invalid label and skip to the next line,
performing no further action.
Dennis Mccunney
============================================================================
===
16) PATH
With MS-Dos 6.0 you CAN exceed the normal path length limit by
putting a "Set Path=C:\;..." in your Config.Sys file instead of
your AutoExec.Bat file. The usual limits do not apply there.
I have put in a path well over 800 characters and it works fine.
The path doesn't display correctly via PATH or SET, but it's in
there and it all gets searched.
I don't recommend having a path that long, mine is normally
only 6-8 directories.
Andrew Barnhardt
============================================================================
===
17) EDLIN
where an EDLIN script is:
-1,#r 1:^Z 1:
-1,#r 2:^Z 2:
-1,#r 3:^Z 3:
-1,#r 4:^Z 4:
-1,#r 5:^Z 5:
-1,#r 6:^Z 6:
-1,#r 7:^Z 7:
-1,#r 8:^Z 8:
-1,#r 9:^Z 9:
e
Note the spaces (one after R, two after ^Z) which prevent replacement
of the second digit in a two digit number.
This will update the last line only, so needs to be done at each
boot. '#' means last line +1. '-1' means the line before the current
one (ie: the last line of the file, if "#" is the current line). Note
that you can only use '-1' in later versions (it works in 5, but not
in 3.30 as far as I know).
Mitch Ames
============================================================================
===
18) DELIMITING CHARACTER:
Prior to DOS 5.0, there was an undocumented DOS function that
would allow you to set the DOS option delimiting character to
something else, like -. Once you did this, you could use either
\ *or* / in PATH specs.
DOS 5.0 removed the function to *set* the option delimiter, but
*retained* the one to query what it currently is! (Don't ask me,
ask M'Soft...) Fortunately, the MKS Toolkit still works with no
apparent glitches.
I believe in pre-DOS 3.X versions that there was a parm you could
provide in CONFIG.SYS to do this, but have no further details.
Just remember: "undocumented" is a synonym for "unsupported, and
not guaranteed to be there next release", which is what happened
in the case I mentioned above.
Dennis Mccunney
============================================================================
===
19) REM IN LINES WITH PIPES OR REDIRECTS
ie: REM echo y | del *.*
Michael Serber reported that he encountered problems when
he tried to REM out an "echo y|del *.*" line in his batch
file. Here is the content of some of the responses he
received in response to his question asking why he experienced
the problem:
It (the problem) appears to only occur if there is a pipe or
redirection in the line (REM'd out), leading me to believe that
DOS first handles pipes and redirections, then goes back to
find out what to do with them.
John Mudge
It's actually doing what it thinks you've told it: piping the
output of REM to DEL. Since REM _has_ no output (remember
REM > NULLFILE?), DEL hangs, waiting for the answer to its
question.
Gary Smith
What is happening here is that DOS reads the entire line, and
always processes redirection and piping *first*, regardless of
where they happen to appear.
Dennis Mccunney
============================================================================
===
20) CALL
The DOS 5.0 manual, in the command reference for CALL, states:
Syntax: call [drive:][path]filename [batch-parameters]
Parameters [drive:][path]filename
Specifies the name and location of the batch program you
want to call. Filename must have a .BAT extension.
The latter sentence is not true in DOS 5.0. CALL works
equally well whether "filename" is a .BAT, .COM, or .EXE
file, or even internal command the following all work
just fine:
call dir
call mem
call tree
call echo Phhhhhhht!
Gary Smith
============================================================================
===
21) CHOICE
I blundered onto an interesting choice.com feature:
CHOICE /C:XM*; /N /T:2,5
if errorlevel=4 goto help
if errorlevel=3 goto end
......etc
The "*" is the escape key, and the ";" is F1 etc.
Robert Lindsay
============================================================================
===
22) MEM /A
If you do a MEM /A it'll give you details of what's in the first meg
of memory.
Windoze owners get MSD.EXE (a pretty undocumented utility), that tells
you this sort of thing. If you do a MEM /A it'll give you details of
what's in the first meg of memory.
Ben Davis
============================================================================
===
23) MOUSE /U
Microsoft mouse driver version 8.1 has a /U switch. Adding that switch
loads all but 3.3k of the driver into HMA. It's not quite the most
recent version mouse driver, but hey, a mouse driver is a mouse driver
is a mouse driver, right? Especially when it only takes 3.3k of ram!
Mark Carter
Are you getting that result by loading the mouse driver high on a 286?
If so, that is good news. Mine takes up 12k of main RAM (MS mouse
driver ver. 7.0).
Gerry Pareja
Mouse 8.0 _is_ able to load itself into HMA (I think) on a 286 by using
the undocumented /U switch. I read it in PC Magazine sometime back.
Also, PC Mag said that the BUFFERS have to be set to a low value, e.g.
5.
Ng Cheng Kiang
============================================================================
===
24) %0
Note that %0 is (almost) always defined as the name of the batch file
itself (including drive\directory as typed at the command line). The
only time %0 is not defined is in Autoexec.bat when run by
Command.com at boot time (or command/p).
Mitch Ames
The %0 parameter is the name of the program. But wait, there's
more. If you want to test for the name of the program you are in!
What do your want to test for?
One time you type "edit", another you type "EDIT", another "EDIT.BAT",
another "C:EDIT.BAT", and another "C:\BELFRY\EDIT.BAT". How many
combinations do you want to test for at the start of your batch file?
You can map the file name to upper case and take care of some of the
problem as follows:
SET SAVEPATH=%PATH%
PATH %0
SET PROGNAME=%PATH%
PATH %SAVEPATH%
SET SAVEPATH=
To do the test, something like this might work:
FOR %%E IN (EDIT EDIT.BAT C:EDIT C:EDIT.BAT C:\BELFRY\EDIT ...
... C:\BELFRY\EDIT.BAT) DO IF '%%E'=='%PROGNAME%' GOTO HIT
ECHO BAD COMMAND OR FILE NAME
GOTO ENDIT
...
:HIT
REM START EXECUTION HERE....
There is one last gotcha to %0. When AUTOEXEC.BAT is run by the bootup
sequence, %0 has no value. This is important if you want to find out
if
you are in AUTOEXEC.BAT, and if you are in AUTOEXEC.BAT for the first
time.
I have seen this work with IBM's PC-DOS 3.10, various flavors of
MS-DOS 3.10, 3.30, 3.31, 4.01, and 5.00. It also seems to work
with DR-DOS 6.0. As to 4DOS, I have no idea, but would welcome
feedback on the matter (although 4DOS and DR-DOS hardly qualify
for a MUF entry....)
Mike Avery
So far as I know, it's not been documented anywhere 'officially',
but I did read about it in an article sometime back, probably
either in PC Magazine or in PC Computing.
Gary Smith
I've never seen it documented - it just bit me one day REAL HARD!
Well, the way I figured it was that when the boot process hands control
to AUTOEXEC.BAT, the normal command line interface isn't used, so %0
never gets set.
Mike Avery
This feature can actually be useful, because you can put
statements like this in your autoexec:
if NOT (%0) == () goto skip
[statements that should not be re-executed go here]
:skip
[statements that can be re-executed go here]
path ...
set ...
etc.
Then you can recreate your bootup environment at any time by
simply typing AUTOEXEC.
Gary Smith
============================================================================
===
25) , . ...
DIR, Using a comma IMMEDIATELY after DIR, shows ALL files, including
the HIDDEN ones.
EXAMPLE: DIR,
Willem van den Broek
This appears only to work with version 5. I tried it with 3.30,
and it didn't display either IO.SYS, MSDOS.SYS (both with S, H
and R attribs) or a test file with A and H attribs.
With version 5 it displayed the test file with H and A, but would
not display IO.SYS or MSDOS.SYS with S, H and R. This doesn't
surprise me actually, since S alone (without H) will prevent
inclusion of a file in a normal DIR.
I didn't try version 4.
Mitch Ames
Interesting: it does for me (display DOS5 IO.SYS and MSDOS.SYS):
However, 4DOS does not do it:
Dennis Mccunney
It was pointed out in the 4DOS echo, and there were people
who said it didn't work for them. But, on my machine
running straight dos6, it works! DIR, (dir comma) in my C:\
shows all files including hidden and system.
Bill George
DIR.. With DOS 6.0 you can get a directory of -all- files (hidden,
system, etc.) with this command.
It was in a PC/Mag. or PC/Comp. issue not too long ago.
Andrew Barnhardt
Have you noticed also how DIR... only displays directories, not
files?
Gary Marden
That's pretty slick. I tried DIR.. and got the parent
directory. DIR... got the current directory subdirs only.
Bill George
Works for any level of directories. ".." will go to the previous
directory as with pure DOS, "..." will go to the directory before
the previous and so on.
Ng Cheng Kiang
In DOS 5.0 it displays directories and files with no extensions.
I tried "DIR ...", "DIR...", and "DIR ....". They all behave
the same way.
Gary Smith
With DOS 5.0 and NDOS 6.0 DIR... gives me a list of
subdirectories off of the root and a list of all files in
the root directory, regardless of the file extension.
It will yield this result regardless of what directory /
subdirectory I am in at the time the command is issued.
Gary Cooper
COMMAND.COM generally seems to ignore excess characters. Try
copying something the AIRPLANES.PLAN, for example, and see what
happens.
Gary Smith
While I was playing around with "dir ..." and trying to see how
it parses to showing all extensionless entities in the current
directory, I noticed that DIR doesn't care if a specified directory
structure exists or not, as long as the overall structure points
back to something that does exist, i.e.
"dir \thisdirdoesnotexist\.."
will ignore the garbage and show the root directory. If
c:\bat exists, then
"dir c:\bat\thisdirdoesnotexist\nordoesthisone\..\.."
will show the c:\bat directory.
Again, absolutely useless as far as i can tell <g>, but interesting.
BTW, has anybody solved the "dir ..." mystery yet? I also noticed
"dir \..." works while "dir \bat\..." fails (any explicitly
specified
directory other than the root generates an "invalid directory"
message).
Paul Leonard
============================================================================
===
26) COPY. A:
The use of a decimal point IMMEDIATELY after some DOS statements,
will replace *.*
EXAMPLES: DEL. (erase all files in current directory)
COPY. A: (copy all files in current directory to A:)
There may be more statements with which it works, but I haven't
tried them yet.
Willem van den Broek
"." means the current directory, and Command.com will assume that
\directory implies \directory\*.* for most commands where a
filename(s) should be specified, eg:
DIR \ is the same as DIR \*.*
COPY \FRED is the same as COPY \FRED\*.*
COPY. A:\ is the same as COPY .\*.* A:\ which is the same as COPY *.*
A:\
DEL. is the same as DEL .\*.* which is the same as DEL *.*
Mitch Ames
Have you noticed also how DIR ... only displays directories, not files?
Gary Marden
In DOS 5.0 it displays directories and files with no extensions.
I tried "DIR ...", "DIR...", and "DIR ....". They all behave
the same way.
Gary Smith
Another good thing is you can travel from directories to
directories without typing "CD". Just type the directory name
followed by a backslash '\'.
Example: To go from C:\BATCH to C:\WP51, you type "\wp51\".
That's it! fast and easy.
Marc Y. Paulin
If you are in the following directory :
\WORD\FILES\LETTERS\APRIL
And wanted to go to the directory \WORD\FILES, you'd normally
type two lines :
CD \
CD WORD\FILES
Or even the single line "CD \WORD\FILES" to combine the two
commands into one. There is a shorter way, simply type the
following : CD ..\.. You're there !
Andrew Barnhardt
In DOS 5.0, it displays files and directories which have no extension.
Larry Kessler
On this machine with DOS 5.0 and NDOS 6.0 DIR... gives me a list of
subdirectories off of the root and a list of all files in the root
directory, regardless of the file extension. It will yield this result
regardless of what directory/subdirectory I am in at the time the
command
is issued.
Gary Cooper
Editor's Note:
I admit that "features" in the last two MUFs may be documented
(although obscure feature), the reason that it continues to be
seen in the MUF list is because I believe that the ability to use
the period immediately IE: COPY. is not documented. What is
documented is the fact that "." and ".." can be used to represent
the current and parent directories respectively, and these will work
with many applications which can handle directory names as arguments.
In this case the "." could also be viewed as a replacement for "*.*"
============================================================================
===
27) MULTIPLE DOS COMMANDS ON ONE LINE
set &=%4&|set n$=%4|set m$=%3|set #=%2|set !=%0
/|\ /|\ /|\ /|\
|_________|_________|________|_________________________Separators
The separators (|) used in the line, are these doing anything
other than separating commands? Can this be used for entering multiple
commands on any line in a batch file regardless of type of command?
Peter Joynson
I believe you are right about this, but I think it pipes any output from
the previous command to the next one (your example doesn't have any
output. For example: ECHO Y|ERASE *.* This would pipe the Y to the
command ERASE *.* so you wouldn't have to enter the Y for the "Are you
sure" prompt.
Robert Hupf
The | is a pipe symbol, well documented in your DOS manual. (Read it
before you read the rest of this message if you don't know about
pipes already, otherwise the rest won't make sense.) Pipes can be
used to put multiple commands on a single line, provided that the
first command does not write anything to StdOout which might cause a
problem when read by the second command as StdIn. Also, it is assumed
that you don't want to see the output of any but the last command,
since each command's output will be piped to the next's input. Note
that in this case SET neither writes anything to StdOut nor reads
StdIn. Thirdly, you must have write access to the current drive, or
%temp% if defined, since a pipe always creates a temporary file. Eg
this would not work if run from a write protected floppy (unless
%temp% was defined), since DOS would fail to create the temporary
files.
Pipes create temporary files even if no actual data is sent to
StdOut because Command effectively treats this:
prog1 | prog2
as something like this:
prog1 > %temp%tempfile
prog2 < %temp%tempfile
del %temp%tempfile
Even if prog1 doesn't create any output, at least one zero length
file is created. To demonstrate, try this
set temp=
set | dir
I must say this beats the usual boring old "how do I echo a blank
line in a batch file" etc.
Mitch Ames
============================================================================
===
28) COM or EXE
Also, have you noticed that 4DOS.COM (when viewed with LIST) begins
with the letters "MZ"? Isn't that the mark of a .EXE file? Very
interesting...
Thomas Smith
It sure is, and that's an example of something else that may be
a MUF. DOS doesn't care whether the extension on an executable
file is .COM or .EXE. It looks at the beginning of the file and
does the right thing according to what it finds.
Gary Smith
============================================================================
===
Editor's Note:
Technically the following information is NOT a MUF, but is included
here due to the fact that it may help save someone a lot of grief!
Similar to advising others not to use delayed cache writes and DOS
6.0's DoubleSpace.
29) CHKDSK
Can you tell me the _date_ of the BAD CHKDSK? I live in
fear of it as I mainly work on other peoples computers an I
have no way of telling if I will destroy their HD with a
simple chkdsk command!
Wallace Mcgee
The only problem with CHKDSK is with large partitions where DOS uses
a 256-sector FAT. Specifically with partition sizes in the ranges of:
127MB-129MB
254MB-258MB
508MB-516MB
1018MB-1030MB
2035MB-2061MB
The date of the CHKDSK that has that problem is 04/09/91. The
replacement being dated 11/11/91.
UNDELETE has the same problem for the same reason.
Bottom line is - if you don't have partitions in these size ranges -
you don't have a problem.
The corrected versions can be had by downloading from the MS BBS.
Probably also available off of CompuServ. The file to look for is:
PD0464.EXE. The phone number for the MS BBS is (206) 936-6735.
Hope that helps you and others with the same question.
Steve Osterday
============================================================================
===
30) DELTREE
Another new, and potentially dangerous, feature of IBM DOS v6.01.
If you were on drive C: and issued the command:
DELTREE /Y \
it would dutifully, and without stopping to ask for verification,
delete your entire drive C:!
(You can test it on a floppy with directories, subdirectories,
and files scattered throughout ... just make sure you specify
and/or are on that drive (disk) when issuing the above command).
Vernon Frazee
============================================================================
===
Well folks, that's it for Vol.1 #6
Please forward any information about other Fabulous MUFs to Gary Cooper
in the FidoNet BatPower echo or at the addresses below.
Gary Cooper, Co-Sysop Programmer's Corner FidoNet 1:255/6.0
gary.cooper.@f6.n255.z1.fidonet.org
I would also appreciate some feedback as to how far and wide the MUF
list travels. A postcard (with some exotic stamps) would be appreciated
as well, and can be forwarded to me at the following snail mail address:
46B Pettingill Rd.
Quispamsis, NB
Canada E2E 3R6
Thanks! Till next time, we return you to your regularly scheduled
BatPower program . . .
Geoff Cutter
> (MicroSoft's Undocumented Features)
>
> Volume 1 Number 6
I have Vol 1 No 7 (Aug 1995)
--
regds Geoff Friday, 1999-02-12
http://www.geocities.com/Athens/Troy/6747/index.html
(last change 98-12-05)
Bert
>
> I blundered onto an interesting choice.com feature:
>
> CHOICE /C:XM*; /N /T:2,5
> if errorlevel=4 goto help
> if errorlevel=3 goto end
> ......etc
>
> The "*" is the escape key, and the ";" is F1 etc.
>
> Robert Lindsay
Really??
If that's true then might work.
G = Up Left Key
H = Up Key
I = Up Right Key
K = Left Key
L = Centre Key
M = Right Key
O = Down Left Key
P = Down Key
Q = Down Right Key
; = F1
< = F2
= = F3
> = F4
? = F5
@ = F6
A = F7
B = F8
C = F9
D = F10
Yup I have just checked them and they do work :)
Cool
--
Bert
Outsider
alpha numeric nor what's available on the keyboard.
I have a password batfile which sounds a siren after
7 attempts to access the computer. The only way to turn
off the siren (besides the off button) is hold down the
Alt key and press 219
Regards,
Outsider
Bert wrote:
>
> >21) CHOICE
> >
> > I blundered onto an interesting choice.com feature:
> >
> > CHOICE /C:XM*; /N /T:2,5
> > if errorlevel=4 goto help
> > if errorlevel=3 goto end
> > ......etc
> >
> > The "*" is the escape key, and the ";" is F1 etc.
> >
> > Robert Lindsay
>
Tom Lavedas
>
> >21) CHOICE
> >
> > I blundered onto an interesting choice.com feature:
> >
> > CHOICE /C:XM*; /N /T:2,5
> > if errorlevel=4 goto help
> > if errorlevel=3 goto end
> > ......etc
> >
> > The "*" is the escape key, and the ";" is F1 etc.
> >
> > Robert Lindsay
>
If you're really interested in using these keys, check out the articles
about extending CHOICE at my web site. There's a way to distiguish
between the F1 key and the semicolon, without having to listen to the
darn beeps that CHOICE puts out when function keys ar struck.
BTW, it's really a bug in CHOICE that can be turned into a 'feature'.
Tom Lavedas
-----------
http://www.pressroom.com/~tglbatch/