MS-DOS secret and/or unknown commands

Below is a listing of MS-DOS commands that are not listed in any available help manual or in the commands syntax or are commonly unknown commands. Many of these commands that are known can be very useful when using MS-DOS, while some of the other commands are unknown and/or appear to do nothing. 
Please use these commands cautiously, some of the commands can erase data and/or erase data without warning.  
ATTRIB ,  The command is short for ATTRIB -a -h -r - s *.* (removes all attributes of a file). 
BACKUP /HP Unknown 
DIR , This lists all files including hidden files, does not work in Windows 95 / 98 / NT / 2000. 
DIR ... Lists all directories that do not have extensions. In Windows 95 / Windows 98 will list the contents of the directories previous to the directory currently in. 
DOSKEY /APPEDIT Utilize doskey functions in MS-DOS command utilities such as edlin and debug. 
DOSKEY /COMMAND Unknown 
DOSKEY /PERMANENT  Unknown 
DOSKEY /SCRSIZE Unknown 
DOSKEY /XHISTORY Unknown 
FDISK /MBR Recreates the Master Boot Record See CH000175 for additional information. 
FDISK /PRI See FDISK Page for additional information. 
FDISK /EXT See FDISK Page for additional information. 
FDISK /LOG See FDISK Page for additional information. 
FDISK /Q Prevents fdisk from booting the system automatically after exiting fdisk.  
FDISK /STATUS Shows you the current status of your hard drives. 
FORMAT /AUTOTEST Formats the hard drive without any prompting. 
FORMAT /BACKUP  Like /AUTOTEST but it will ask you for a volume label. 
FORMAT /Z:n Command used with FDISK supporting FAT32, used to specify the cluster size in bytes where n is multiplied by 512. 
MEM /A or /ALL Adds a line into the MEM command tells the available space in HMA. 
RESTORE /Y Unknown 
RESTORE /Z Unknown 
SET DIRCMD=0 Will make all directories hidden however still accessible, to get them back SET DIRCMD= 
SHARE /NC Unknown 
TRUENAME When placed before a file, will display the whole directory in which it exists. 
VER /R Tells you the Revision and if DOS is in HMA. 
DOS TOP 10 COMMANDS
Below is a listing of the top 10 MS-DOS commands most commonly used and that you will most likely use during a normal DOS session. 
 1. cd   2. dir 
 3. copy   4. del 
 5. edit   6. move 
 7. ren (rename)  8. deltree 
 9. cls   10. format 
TOP 10 COMMAND PAGES
 Below is a listing of the top 10 MS-DOS command pages by the amount of times they have been accessed on the Computer Hope server.
 1. fdisk   2. format 
 3. copy   4. xcopy 
 5. dir   6. cd 
 7. deltree   8. net 
 9. Ansi   10. ping