The command redirects requests for disk operations on one drive to a different drive.
* x The drive letter to reassign.
* y The drive letter that x: will be assigned to.
* /STATUS Displays the current drive assignments.
If typed without parameters then all drive letters are reset to original assignments.
The command is available in MS-DOS 5.00.
Display or sets the search path for data files. DOS will search the specified path(s) if the file is not found in the current path. This had some creative uses, such as allowing non-CD based games to be run from the CD, with configuration/save files stored on the HD.
Change or view the attributes of one or more files. It defaults to displaying the attributes of all files in the current directory.
* To add an attribute attach a ‘+’ in front of it.
* To remove an attribute attach a ‘-‘ in front of it
* Attributes include
o R – Read-only
o A – Archive
o S – System
o H – Hidden
attrib [+|-ahrs] [filespec]
Directory Attrib Functions: It is also possible to use ATTRIB across directories.
Specifies a file or files for attrib to process.
o /D – Process folders as well.
o /S – Process matching files in the current folder and all subfolders.
Roughly equivalent to the Unix commands chattr and lsattr.
Calls one batch program from another. A new batch file context is created with the specified arguments and control is passed to the statement after the label specified.
call [filespec][batch file parameters]
* filespec: name and if necessary path of the new batch file
* parameters: switches
5. cd or chdir
Change current directory. Displays the current working directory when used without a path parameter.
displays the current working directory on the current drive.
displays the current working directory on F:.
changes the working directory on the current drive to directory.
changes the working directory on E: to directory.
changes the working directory to the parent directory (up one directory level).
changes the working directory to the root (top level) directory of the current drive.
Equivalent to the Unix command cd (with a path parameter), or pwd (without a parameter). cd .. changes to the parent directory.
Changes the code page used to display character glyphs in a console window.
With a numeric parameter, this command changes the codepage setting to codepage. Without a parameter, the command displays the currently active codepage.
Verifies a hard disk or a floppy disk for file system integrity.
* /F :
* /P : Forces a full disk verification
* /R : Searches for defective sectors and recovers legible information (applies /F)
chkdsk drive [[path]filename] [/F] [/V]
Equivalent to the Unix command fsck
Allows for batch files to prompt the user to select one item from a set of single-character choices.
Introduced in MS-DOS 6; DR-DOS 7.03.
Clears the screen.
Equivalent to the Unix clear.
Copies files from one location to another. The destination defaults to the current directory. If multiple source files are indicated, the destination must be a directory, or an error will result.
copy filespec [destination]
Files may be copied to devices. For example, copy file lpt1 sends the file to the printer on LPT1. copy file con outputs file to the screen (“console”), which can also be done using type file. Devices themselves may be copied: copy con file takes the text typed into the console and puts it into file, stopping when EOF (Ctrl+Z) is typed.
Files may be concatenated using +. For example, copy file1+file2 file_cat will concatenate the files and output them as file_cat. There are two switches to modify the command’s behaviour, /a (text mode, the default) and /b (binary mode). In text mode, copy will stop when it reaches the EOF character; in binary mode, the files will be concatenated in their entirety, ignoring EOF characters. Examples:
copy /a alpha.txt + beta.txt gamma.txt
copy /b alpha.mpg + beta.mpg gamma.mpg
Equivalent Unix commands are cp (for copying) and cat (for concatenation). Device files may be copied in Unix as well, e.g. cp file /dev/tty will display a file on the screen (but cat file is more commonly used here).
Equivalent RT-11/RSX-11/OpenVMS command is copy.
(in MS/PC-DOS; diskopt in DR-DOS)
Defragments a disk drive.
* -A – Analyses the fragmentation of a disk drive
* -F – Force defragmentation even if disk space is low
* -V – Verbose output mode
Example of usage:
defrag driveletter: -a -v
No Unix equivalent.
12. del or erase
Deletes one or more files.
Equivalent to the Unix command rm.
Equivalent in RT-11/RSX-11/OpenVMS operating systems line is delete command which can be contracted to del.
Deletes a directory along with all of the files and subdirectories that it contains. Normally, it will ask for confirmation of such a drastic action.
deltree [/y] directory
The /y parameter, if present, tells the deltree command to carry out without first prompting for confirmation.
The deltree command is not included in recent Microsoft Windows operating systems. Deleting a non-empty directory in those versions of Windows where the command is not included, can be achieved by using the rmdir command as in the following example:
rmdir /s [/q] directory
In Unix, the functionality of deltree is provided by the rm command with the parameter -r (or -rf for the /y switch).
Lists the contents of a directory.
The dir command typed by itself, displays the disk’s volume label and serial number; one directory or filename per line, including the filename extension, the file size in bytes, and the date and time the file was last modified; and the total number of files listed, their cumulative size, and the free space (in bytes) remaining on the disk. The command is one of the few commands that exist from the first versions of DOS.
dir [drive:][path][filename] [parameters]
Most commonly used parameters of dir include:
* /W : Displays the listing in wide format, with as many as five filenames or directory names on each line.
* /P : Pause at every page
* /S : Also look in subdirectories
* /Axx: Display files with the specified attributes only
* /Oxx: Modifies sort order
* /B : Uses bare format (no heading information or summary)
* > [drive:][path][filename] : To Store Result in a text file;(c:\dir > c:\fileList.txt)
Possible attributes for the A parameter are D (directories), R (read-only files), H (hidden files), A (files/directories with the archive bit on), and S (system files). The prefix – negates an attribute; attributes can be combined (e.g. /AA means directories with the archive bit on).
Possible sort orders are N (name), S (size), E (extension), D (date and time), A (last access date), and G (group directories first). The prefix – reverses the order.
Other less commonly used parameters of dir include:
* /D : Display wide format but sorted by column
* /L : Display forced into lowercase
* /N : Display forced into long file name format instead of 8.3
* /Q : Displays the owner of each file
* /X : Display shows 8.3 names next to long file names
The default parameters of dir can be set using the DIRCMD environment variable.
Equivalent to the Unix command ls (the option -l is “long” list format, it works the opposite way from /w.)
Equivalent in RT-11/RSX-11/OpenVMS operating systems line is directory command which can be contracted to dir.
Prints its own arguments back out to the DOS equivalent of the standard output stream. Usually, this means directly to the screen, but the output of echo can be redirected like any other command. Often used in batch files to print text out to the user.
echo this is text Outputs ‘this is text’
echo. Outputs a blank line
Another important use of the echo command is to toggle echoing of commands on and off in batch files.
echo on turns on echoing of commands
echo off turns off echoing of commands
Traditionally batch files begin with the @echo off statement. This says to the interpreter that echoing of commands should be off during the whole execution of the batch file thus resulting in a “tidier” output. The @ symbol declares that this particular command (echo off) should also be executed without echo. For example the following 2 batch files are equivalent:
echo The files in your root directory:
dir /b /a-d c:\
@echo The files in your root directory:
@dir /b /a-d c:\
Echo can be used to write to files directly from the console, by redirecting the output stream:
echo text > filename
Echo can also be used to append to files directly from the console, again by redirecting the output stream:
echo text >> filename
To type more than one line from the console into a file, use copy con (above).
Equivalent to the Unix command echo.
Converts an executable (.exe) file into a binary file with the extension .com, which is a memory image of the program.
The size of the resident code and data sections combined in the input .exe file must be less than 64KB. The file must also have no stack segment.
Exits the current command processor. If the exit is used at the primary command, it has no effect unless in a DOS window under Microsoft Windows, in which case the window is closed and the user returns to the desktop.
Exit also exists in Unix-shells. If an exit command is used in the primary command shell under Unix, however, it will logoff the user, similar to the control-D keystroke.
Main article: FASTOPEN
19. fc or comp
Compares two files or sets of files and displays the differences between them.
FC [/A] [/C] [/L] [/LBn] [/N] [/T] [/W] [/nnnn] [drive1:][path1]filename1 [drive2:][path2]filename2
FC /B [drive1:][path1]filename1 [drive2:][path2]filename2
/A Displays only first and last lines for each set of differences.
/B Performs a binary comparison.
/C Disregards the case of letters.
/L Compares files as ASCII text.
/LBn Sets the maximum consecutive mismatches to the specified number of lines.
/N Displays the line numbers on an ASCII comparison.
/T Does not expand tabs to spaces.
/W Compresses white space (tabs and spaces) for comparison.
/nnnn Specifies the number of consecutive lines that must match after a mismatch.
[drive1:][path1]filename1 Specifies the first file or set of files to compare.
[drive2:][path2]filename2 Specifies the second file or set of files to compare.
Equivalent to the Unix commands comm, cmp and diff.20. fdisk
Manipulates hard disk partition tables. The name derives from IBM’s habit of calling hard drives fixed disks. When run from the command line, it displays a menu of various partitioning operations:
1. Create DOS partition or Logical DOS Drive
2. Set active partition
3. Delete partition or Logical DOS Drive
4. Display partition information
5. Change current fixed disk drive (only available if the computer has more than one hard drive)
FDISK /MBR installs a standard master boot record on the hard drive.
FDISK /MBR #: where # is other partition on system. Completes above command on indicated partition.
eg: “C:\FDISK /MBR D:” would install boot record on D:\ partition.
Fdisk exists under Unix with the same name, but it is an entirely different program. However they share purposes.
A filter to find lines in the input data stream that contain or don’t contain a specified string and send these to the output data stream.
Find may also be used as a pipe.
find “keyword” < ”inputfilename” > ”outputfilename”
Searches for a text string in a file or files.
FIND [/V] [/C] [/N] [/I] “string” [[drive:][path]filename[ …]]
/V Displays all lines NOT containing the specified string.
/C Displays only the count of lines containing the string.
/N Displays line numbers with the displayed lines.
/I Ignores the case of characters when searching for the string.
“string” Specifies the text string to find.
[drive:][path]filename Specifies a file or files to search.
If a pathname is not specified, FIND searches the text typed at the prompt
or piped from another command.
Equivalent to the Unix command grep. The Unix command find performs an entirely different function.
Delete all the files on the disk and reformat it for MS-DOS
In most cases, this should only be used on floppy drives or other removable media. This command can potentially erase everything on a computer’s hard disk.
/autotest and /backup are undocumented features. Both will format the drive without a confirmation prompt.
format [options] drive
FORMAT drive: [/V[:label]] [/Q] [/F:size] [/B | /S] [/C]
FORMAT drive: [/V[:label]] [/Q] [/T:tracks /N:sectors] [/B | /S] [/C]
FORMAT drive: [/V[:label]] [/Q] [/1] [/4] [/B | /S] [/C]
FORMAT drive: [/Q] [/1] [/4] [/8] [/B | /S] [/C]
/V[:label] Specifies the volume label.
/Q Performs a quick format.
/F:size Specifies the size of the floppy disk to format (such
as 160, 180, 320, 360, 720, 1.2, 1.44, 2.88).
/B Allocates space on the formatted disk for system files.
/S Copies system files to the formatted disk.
/T:tracks Specifies the number of tracks per disk side.
/N:sectors Specifies the number of sectors per track.
/1 Formats a single side of a floppy disk.
/4 Formats a 5.25-inch 360K floppy disk in a high-density drive.
/8 Formats eight sectors per track.
/C Tests clusters that are currently marked “bad.”
Known as a joke among UNIX users of that time since every user on the machine could easily cause damage with just one command. Therefore, it was known in the UNIX community as “The big DOS timesaver”.
There is also an undocumented /u parameter for “unconditional” that will write strings of zeros on every sector.
Equivalent to the Unix command mkfs.
Equivalent in RT-11/RSX-11/OpenVMS operating systems line is format command which can not create filesystem. After formatting one should use initialize (contracted to init) command to create filesystem (Equivalent to MS-DOS command format /q or “quick format”).
Gives help about DOS.
help ‘command’ would give help on a specific command. By itself, it lists the contents of DOSHELP.HLP. Help for a specific command invokes the command with the /? option. In MS-DOS 6.x this command exists as FASTHELP.
MS-DOS 6.xx help command uses QBASIC to view a quickhelp HELP.HLP file, which contains more extensive information on the commands, with some hyperlinking etc. The MS-DOS 6.22 help system is included on Windows 9x cdrom versions as well.
PC-DOS 7.xx help uses view.exe to open OS/2 style .INF files (cmdref.inf, dosrexx.inf and doserror.inf), opening these to the appropriate pages.
In DR-DOS, help is a batch file that launches DR-DOS’ online reference, dosbook.
Windows NT, all versions, uses DOS 5 style help, but versions before VISTA have also a Windows help file (NTCMDS.HLP or NTCMDS.INF) in a similar style to MS-DOS 6.
FreeDOS uses an HTML help system, which views HTML help files on a specified path. The path is stored in HELPPATH environment variable, if not specified, default path is \HELP on the drive which HELP is placed.
Partially equivalent to the Unix command man.
24. intersvr & interlnk
(in MS-DOS; filelink in DR-DOS)
Network PCs using a null modem cable or LapLink cable. The server-side version of InterLnk, it also immobilizes the machine it’s running on as it is an active app (As opposed to a TSR) which must be running for any transfer to take place. DR-DOS’ filelink is executed on both the client and server.
New in MS-DOS 6.
No direct Unix equivalent, though some Unices offer the ability to network computers with TCP/IP through null modem or Laplink cables using PLIP or SLIP.
Attaches a drive letter to a specified directory on another drive.
JOIN d: [d:\path]
JOIN [/D] (removes drive assignment)
If JOIN a: c:\floppy were executed, c:\floppy would display the contents of the a: drive. The opposite can be achieved via the subst command.
Changes the label on a logical drive, such as a hard disk partition or a floppy disk.
In Unix and Unix-like systems, this differs from filesystem to filesystem. e2label can be used for ext2 partitions.
Loads a program above the first 64K of memory, and runs the program.
Included only in MS/PC-DOS. DR-DOS used memmax, which opened or closed lower, upper, and video memory access, to block the lower 64K of memory.
28. md or mkdir
Makes a new directory. The parent of the directory specified will be created if it does not already exist.
Equivalent to the Unix command mkdir.
Displays memory usage.
o /CLASSIFY or /C – Lists the size of programs, provides a summary of memory in use and lists largest memory block available.
o /DEBUG or /D – Displays status of programs, internal drivers, and other information.
o /PROGRAM or /P Displays status of programs currently loaded in memory.
Equivalent to the Unix command free.
Starting from version 6, MS-DOS included the external program MemMaker which was used to free system memory (especially Conventional memory) by automatically reconfiguring the AUTOEXEC.BAT and CONFIG.SYS files. This was usually done by moving TSR Programs to the Upper memory. The whole process required three system restarts. Before the first restart the user was asked whether he wanted to enable EMS Memory or not.
The use of MemMaker was popular among gamers who wanted to enable or disable Expanded memory in order to run a game which required EMS or not. Better results could be achieved by an experienced user manually configuring the startup files to achieve greater free memory yield.
* /BATCH Runs MemMaker in batch (unattended) mode. In batch mode, MemMaker takes the default action at all prompts.
* /UNDO Instructs MemMaker to undo its most recent changes.
PC-DOS uses another program RamBoost to optimize memory, either the HIMEM/EMM386 or a third-party memory manager.
Configures system devices. Changes graphics modes, adjusts keyboard settings, prepares code pages, and sets up port redirection.
Pages through the output so that you can view more than one screen of text.
command | more
Equivalent to the Unix commands more and less.
More may also be used as a filter.
more < inputfilename
Moves files or renames directories.
move filename newname
move driveletter:\olddir driveletter:\newdir
Example: move c:\old c:\new
Equivalent to the Unix command mv. DR-DOS used a separate command for renaming directories, rendir.
Main article: Microsoft Diagnostics
Provides detailed technical information about the computer’s hardware and software.
New in MS-DOS 6; the PC-DOS version of this command is QCONFIG.
No Unix equivalent, however in GNU/Linux similar type of information may be obtained from various text files in /proc directory.
Suspends processing of a batch program and displays the message ‘Press any key to continue. . .’.
Parks the hard disk heads in order to enable safe shutdown; only used on early versions.
No Unix equivalent.
MS-DOS 3.2 (and possibly others) used the command HHSET
Adds a file in the print queue.
* /D device : Specifies the name of the print devices. Default value is LPT1
* /P filename : Add files in the print queue
* /T : Removes all files from the print queue
* /C filename : Removes a file from the print queue
This command was introduced in MS-DOS version 2. Before that there was no built-in support for background printing files. The user would usually use the copy command to copy files to LPT1.
Equivalent to the Unix command lpr
38. rd or rmdir
Remove a directory, which by default must be empty of files for the command to succeed (the /s flag removes this restriction).
Equivalent to the Unix command rmdir.
Remark statement, normally used within a batch file. An alternative way not to run a specific statement in a batch file is creating a label that will never be used, ::.
On the command line, rem can also be used to create a zero length file by redirecting an empty remark statement to a filename.
rem > newfilename
In Unix, the # sign can be used to start a comment; the zero-length file can be achieved using various methods, such as the touch command or dd.
Renames a file. Unlike the move command, this command cannot be used to rename subdirectories, or rename files across drives.
ren filename newname
You can rename files in another directory by using the PATH parameter:
ren [path]|[filename] [newfilename]
An example could be:
ren c:\Windows filex.txt filey.txt
On DOS with long filename support, care must be taken when directories have spaces in their names like “Documents and Settings”. In these cases double-quotes are used to enclose them:
ren c:\”Documents and Settings”\”All Users”\Desktop filex.txt filey.txt
Mass renames can be accomplished by the use of wildcards. For example, the following command will change the extension of all files in the current directory which currently have the extension htm to html:
ren *.htm *.html
In Unix, this functionality of a simple move is provided by the mv command, while batch renames can be done using the rename command.
Disk diagnostic utility. Scandisk was a replacement for the chkdsk utility, starting with later versions of MS-DOS. Its primary advantages over chkdsk is that it is more reliable and has the ability to run a surface scan which finds and marks bad clusters on the disk. chkdsk had surface scan and bad cluster detection functionality included, and was used again on Windows NT based operating systems.
Equivalent to the Unix command fsck.
Sets environmental variables. See Environment variable.
Since Windows 2000 it can be even used for command line inputs by using Parameter /P
set /p choice=Type your text.
echo You typed: “%choice%”
Installs support for file sharing and locking capabilities.
share [/F:space] [/L:locks]
/F:space Allocates file space (in bytes) for file-sharing information.
/L:locks Sets the number of files that can be locked at one time.
A filter to sort lines in the input data stream and send them to the output data stream.
sort < inputfilename > outputfilename
Equivalent to the Unix command sort.
A utility to map a subdirectory to a drive letter.
subst <d:> <path>
subst <d:> /D (Deletes the substitute drive)
If SUBST e: c:\edrive were executed, a new drive letter e: would be created, showing the contents of c:\edrive. The opposite can be achieved via the join command.
A utility to make a volume bootable.
48. time and date
Display and set the time and date
When these commands are called from the command line or a batch file, they will display the time or date and wait for the user to type a new time or date and press RETURN. The command ‘time /t’ will bypass asking the user to reset the time.
The Unix command date displays both the time and date, but does not allow the normal users to change either. Users with superuser privileges may use date -s <new-date-time> to change the time and date.
The Unix command time performs a different function.
Shows the directory tree of the current directory
/F (Displays the names of the files in each folder.)
/A (Use ASCII instead of the extended characters.)
/? (Shows the help)
tree [options] [directory]
If typed without a parameter then the current active drive pathname is displayed.
If typed with a parameter then the command outputs the entire path (full directory and filename) of the path or filename. For example, if the working drive and directory were C:\PROGRAMS and one typed truename fish, the output would be C:\PROGRAMS\FISH. This command also displays the UNC pathnames of mapped network or local CD drives.
This command is an undocumented DOS command. The help switch “/?” defines it as a “Reserved command name”. It is available in MS-DOS 5.00.
This command is similar to the Unix which command, which, given an executable found in $PATH, would give a full path and name. The C library function realpath performs this function.
Display a file. The more command is frequently used in conjunction with this command, e.g. type long-text-file | more.
Equivalent to the Unix command cat.
Restores file previously deleted with del. By default all recoverable files in the working directory are restored. The options are used to change this behavior. If the MS-DOS mirror TSR program is used, then deletion tracking files are created and can be used by undelete.
* /list : lists the files that can be undeleted.
* /all : Recovers all deleted files without prompting. Uses a number sign for missing first character.
* /dos : Recover only MS-DOS aware files, ignore deletion tracking file.
* /dt : Recover only deletion tracking file aware files.
In Unix and Unix-like systems this differs from filesystem to filesystem. People who use the ext2 filesystem can try the command e2undel.
Shows the version of MS-DOS you are using.
Some versions of MS-DOS support an undocumented /r switch, which will show the revision as well as the version.
Roughly equivalent to the Unix command uname.
Enables or disables the feature to determine if files have been correctly written to disk.
If no parameter is provided, the command will display the current setting.
Copy entire directory trees.
xcopy directory [destination-directory]
Equivalent to the Unix command cp when used with -r parameter.