DOS non-public Commands and Parameters _dos/bat

There are many commands and parameters that are not exposed in the DOS system. I've been collecting and sorting out a lot. Because there are several kinds of DOS, the following only takes MS-DOS as an example to describe the commands and parameters that are not exposed in common commands. After comparison, I found that in each version of MS-DOS, the unpublished commands and parameters in the 7.x version are the most, and the unpublished commands and parameters in these 7.x versions are usually not available in other DOS versions, but they are very useful, such as the command/z command, This is the only way to display the ERRORLEVEL (Error return code) value with a DOS command (of course, with other add-ons, such as err2env).

DOS not public command:

Truename: Used to display the actual path, useful for commands such as subst.
Installhigh: Used in Config.sys to transfer files to UMB.
Logos and Comment: Only used in Config.sys in MS-DOS 7.x, the usage is unknown.

DOS not exposed parameters:

Command/f makes fail the default option in Abort,retry,fail.
COMMAND/D in DOS5 is prohibited Autoexec.bat automatic execution, in the 6.0+ version is the Forbidden/F parameter.
COMMAND/Z displays ERRORLEVEL (Error return code) information.
COMMAND/T forces Command.com to be permanently transferred to normal memory in MS-DOS 7.x.

Format/autotest automatically completes the formatting process.
Format/backup automatically completes the formatting process and prompts for the volume label.
Format/select only backs up system area data on disk, equivalent to mirror program.
format/select/u the boot area and the file allocation table with F6H.
FORMAT/Z:N sets the cluster size on the FAT32 partition.

FDISK/MBR rewrite the hard drive master boot record.
FDISK/CMBR Drive overrides the master boot record on the specified drive.
Fdisk/pri:size create the primary partition.
Fdisk/ext:size create an extended partition.
Fdisk/log:size creates a logical drive on an extended partition.
fdisk/prmt|/q prompt action/quiet mode.
Fdisk/partn saves the partition table information to Partsav.fil.
Fdisk/actok is used in MS-DOS 7.x to skip integrity testing.
FDISK/FPRMT is used in MS-DOS 7.x, automatically takes the FAT32 and skips the hint message.

Doskey/appedit enables DOSKEY to also be used in other programs, such as Debug, and so on.
Doskey/command and/permanent and/scrsize and/xhistory usages are unknown.

Scandisk/clip is used in MS-DOS 7.x to cut a long file name to a short one.
Scandisk/nolost is used in MS-DOS 7.x without prompting for surface testing or missing clusters.
Scandisk/noui and/text are used in MS-DOS 7.x with a standard DOS interface.
Scandisk/mount is equivalent to the mount=always in Scandisk.ini.
Scandisk/time is equivalent to the Scantimeout=on in Scandisk.ini.

Qbasic/qhelp access to the full screen Help system for DOS, which is equivalent to executing the assist command.
Qbasic/edcom into the DOS file editor, which is equivalent to executing the edit command.

mem/a or Mem/all displays HMA information.

VER/R Displays the extended version information.

Dir/z is used in MS-DOS 7.x to indicate that long file names are not displayed.

Device=himem. sys/q Use Quiet mode when the Himem.sys is loaded.

Device=emm386. EXE NOTR do not detect token Ring network adapters.

DOS Not public usage:

IF EXIST XMSXXXX0 ... This command can determine whether the XMS memory manager (usually Himem.sys) is currently installed. Note: It is XMSXXXX0, not the wrong XMMXXXX0 mentioned in some articles.
IF EXIST EMMXXXX0 ... This command is used to determine whether the EMS memory Manager (usually EMM386.EXE) is currently installed.

:: This symbol can be used in batch files instead of REM annotation commands to speed up the operation.

These are not public commands and parameters in MS-DOS, some of which are very practical, we might as well try.