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In the PC operating systems MS-DOS and PC DOS, a number of standard system commands were provided for common tasks such as listing files on a disk or moving files. Some commands were built into the command interpreter, others existed as external commands on disk. Over the several generations of DOS, commands were added for the additional functions of the operating system. In the current Microsoft Windows operating system, a text-mode command prompt window can still be used.
The command interpreter for DOS (COMMAND.COM) runs when no application programs are running. When an application exits, if the transient portion of the command interpreter in memory was overwritten, DOS will reload it from disk. Some commands are internal — built into COMMAND.COM; others are external commands stored on disk. When the user types a line of text at the operating system command prompt, COMMAND.COM will parse the line and attempt to match a command name to a built-in command or to the name of an executable program file or batch file on disk. If no match is found, an error message is printed, and the command prompt is refreshed.
External commands were too large to keep in the command processor, or were less frequently used. Such utility programs would be stored on disk and loaded just like regular application programs but were distributed with the operating system. Copies of these utility command programs had to be on an accessible disk, either on the current drive or on the command path set in the command interpreter.
In the list below, commands that can accept more than one filename, or a filename including wildcards (* and ?), are said to accept a filespec (file specification) parameter. Commands that can accept only a single filename are said to accept a filename parameter. Additionally, command line switches, or other parameter strings, can be supplied on the command line. Spaces and symbols such as a "/" or a "-" may be used to allow the command processor to parse the command line into filenames, file specifications, and other options.
The command interpreter preserves the case of whatever parameters are passed to commands, but the command names themselves and filenames are case-insensitive.
A partial list of the most common commands for MS-DOS follows.
Displays 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 has some creative uses, such as allowing non-CD based games to be run from the CD, using configuration/save files stored on the hard drive.
The command redirects requests for disk operations on one drive to a different drive. It can also display drive assignments or reset all drive letters to their original assignments. The command is available in MS-DOS 5.00.
Attrib changes or views the attributes of one or more files. It defaults to displaying the attributes of all files in the current directory. The file attributes available include read-only, archive, system, and hidden attributes. The command has the capability to process whole folders and subfolders of files. the command is roughly equivalent to the Unix commands
These are commands to back up and restore files from an external disk. These appeared in version 2, and continued to PC DOS 5 and MS-DOS 6 (PC DOS 7 had a deversioned check). In DOS 6, these were replaced by commercial programs (CPBACKUP, MSBACKUP), which allowed files to be restored to different locations.
An implementation of the BASIC programming language for PCs. The Basic language as implemented by this was a very common operating system on 8- and 16-bit machines that were made in the 1980's.
IBM computers had BASIC 1.1 in ROM, and IBM's versions of BASIC used code in this ROM-BASIC, which allowed for extra memory in the code area. BASICA last appeared in IBMDOS 5.02, and in OS/2 (2.0 and later), the version had ROMBASIC moved into the program code.
Microsoft released GW-BASIC for machines with no ROM-BASIC. Some OEM releases had basic.com and basica.com as loaders for GW-BASIC.EXE.
Basic was dropped after MS-DOS 4, and PC DOS 5.02. OS/2 (which uses PC DOS 5), has it, while NT (MS-DOS 5) does not.
Given a batch filename and run parameters, the CALL command invokes one batch program from another batch program. A new batch file context is created with the specified arguments and control is passed to the statement after the label specified.
The CHDIR (or the alternative name CD) command either displays or changes the current working directory. The analogous commands in Unix are
cd (change working directory), or
pwd (display working directory).
The command either displays or changes the active code page used to display character glyphs in a console window. The codepage 1252 lets one use the Windows GUI charset in the command line, while codepage 65001 corresponds to the Unicode utf-8 encoding.
CHKDSK verifies a storage volume (for example, a hard disk, disk partition or floppy disk) for file system integrity. The command has the ability to fix errors on a volume and recover information from defective disk sectors of a volume. It is analogous to the Unix command
The CHOICE command is used in batch files to prompt the user to select one item from a set of single-character choices. Choice was introduced as an external command with MS-DOS 6.0; Novell DOS 7 and PC DOS 7.0. Earlier versions of DR DOS supported this function with the built-in switch command (for numeric choices) or by beginning a command with a question mark. This command was formerly called ync (yes-no-cancel).
The CLS or CLRSCR command clears the terminal screen. It is analogous to the Unix
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 has the ability to concatenate files. The command can copy in text mode or binary mode; n 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. The analogous Unix commands are
cp (for copying) and
cat (for concatenation). The analogous RT-11, RSX-11, and OpenVMS command is
Files may be copied to devices. For example,
copy file con outputs file to the screen console. Devices themselves may be copied to a destination file, for example,
copy con file takes the text typed into the console and puts it into file, stopping when EOF (Ctrl+Z) is typed.
Defines the terminal device (for example, COM1) to use for input and output.
The command has the ability to analyze the file fragmentation on a disk drive or to defragment a drive. The command is called DEFRAG in MS-DOS/PC DOS and diskopt in DR-DOS. The is no Unix equivalent.
DEL (or the alternative form ERASE) is used to delete one or more files. The analogous Unix command is
rm and the analogous RT-11/RSX-11/OpenVMS command is
Deletes a directory along with all of the files and subdirectories that it contains. Normally, it will ask for confirmation of the potentially dangerous action.
deltree command is included in certain versions of Microsoft Windows and Microsoft DOS Operating Systems. It is specifically available only in versions of MS-DOS 6.0 and higher, and in Microsoft Windows 9x. In Microsoft Windows NT, the functionality provided exists but is handled by the command rd or rmdir which has slightly different syntax. This command has been deprecated for windows7. In Unix, the functionality of
deltree is provided by the
The DIR command displays the contents of a directory. The contents comprise 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. The command can display files in subdirectories. The resulting directory listing can be sorted by various criteria and filenames can be displayed in a chosen format. The analogous Unix command is
ls and the analogous RT-11/RSX-11/OpenVMS command is
The ECHO command 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, to files or devices. Often used in batch files to print text out to the user.
Another important use of the echo command is to toggle echoing of commands on and off in batch files. 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.)
The analogous command in Unix is
EDIT is a full-screen text editor, included with MS-DOS 5 and 6, OS/2 and Windows NT to 4.0 The corresponding program in Windows 95 and later, and W2k and later is Edit v2.0. PC DOS 6 and later use the DOS E Editor and DR-DOS used editor up to version 7.
DOS line-editor. It can be used with a script file, like debug, this makes it of some use even today. The absence of a console editor in MS-DOS/PC DOS 1-4 created an after-market for third-party editors.
In DOS 5, an extra command "?" was added to give the user much needed help.
DOS 6 was the last version to contain EDLIN, for MS-DOS 6, it's on the supplemental disks, PC DOS 6 had it in the base install. Windows NT 32-bit, and OS/2 have Edlin.
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.
Show differences between any two files, or any two sets of files.
The FDISK command anipulates hard disk partition tables. The name derives from IBM's habit of calling hard drives fixed disks. FDISK has the ability to display information about, create, and delete DOS partitions or logical DOS drive. It can also install a standard master boot record on the hard drive.
The FIND command is 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. It may also be used as a pipe. The analogous command in Unix is
grep; the Unix command
find performs an entirely different function analogous to
The FOR loop can be used to parse a file or the output of a command.
Deletes the FAT entries and the root directory of the drive/partition, and reformats 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. The analogous command in Unix is
mkfs, and in RT-11/RSX-11/OpenVMS it is the
Gives help about DOS commands.
\HELPon the drive which HELP is placed.
Partially equivalent to the Unix command man.
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 PC DOS 5.02, MS-DOS 6.0
The JOIN command attaches a drive letter to a specified directory on another drive.
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. The command is included only in MS-DOS/PC DOS. DR-DOS used memmax, which opened or closed lower, upper, and video memory access, to block the lower 64K of memory.
hiload in DR-DOS.
Makes a new directory. The parent of the directory specified will be created if it does not already exist. Equivalent to the Unix command
Displays memory usage. It is capable of displaying program size and status, memory in use, and internal drivers. Equivalent to the Unix command
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/she wanted to enable EMS Memory. The use of MemMaker was popular among gamers who wanted to enable or disable Expanded memory in order to run a game. PC DOS uses another program RamBoost to optimize memory, either the HIMEM/EMM386 or a third-party memory manager.
Moves files or renames directories. Equivalent to the Unix command
mv. DR-DOS used a separate command for renaming directories,
The MSD command provides detailed technical information about the computer's hardware and software. MSD was new in MS-DOS 6; the PC DOS version of this command is QCONFIG. The command appeared first in Word2, and then in Windows 3.10. No Unix equivalent, however in GNU/Linux similar type of information may be obtained from various text files in /proc directory.
Displays or sets a search path for executable files.
Suspends processing of a batch program and displays the message 'Press any key to continue. . .'. This command exists in all versions of Microsoft Windows and has the exact same function, except in windows7. In windows7 it just pauses it.
The PRINT command adds or removes files in 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 commands
Remove a directory (delete a directory); by default the directories must be empty of files for the command to succeed. The deltree command in some versions of MS-DOS and all versions of Windows 9x removes non-empty directories.
Remark command, normally used within a batch file, and for DR-DOS, PC/MS-DOS 6 and above, in CONFIG.SYS. This command is processed by the command processor. Thus, its output can be redirected to create a zero-byte file. REM is useful in logged sessions or screen-captures. One might add comments by way of labels, usually starting with double-colon ::. These are not processed by the command processor. In Unix, the
# sign can be used to start a comment.
The REN command renames a file. Unlike the
move command, this command cannot be used to rename subdirectories, or rename files across drives. Mass renames can be accomplished by the use of wildcards. In Unix, this functionality of a simple move is provided by the
mv command, while batch renames can be done using the
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. It also provided mouse point-and-click TUI, allowing for interactive session to complement command-line batch run.
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
Sets environmental variables. CMD.EXE in Windows NT 2000, 4DOS, 4OS2, 4NT, and a number of third-party solutions allow direct entry of environment variables from the command prompt. From at least Windows 2000, the
set command allows for the evaluation of strings into variables, thus providing inter alia a means of performing integer arithmetic.
TSR designed to return a different value to the version of DOS that is running. This allows programs that look for a specific version of DOS to run under a different DOS.
Setver appeared in version 4, and has been in every version of DOS, OS/2 and Windows NT since.
Installs support for file sharing and locking capabilities.
A utility to map a subdirectory to a drive letter.
A utility to make a volume bootable. Sys rewrites the Volume Boot Code (the first sector of the partition that Sys is acting on) so that the code, when executed, will look for Io.sys. Sys also copies the core DOS system files, Io.sys, Msdos.sys, and Command.com, to the volume. Sys does NOT rewrite the Master Boot Record, contrary to widely-held belief.
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 Unix command
date displays both the time and date, but does not allow the normal users to change either. Users with superuser privileges may change the time and date. The Unix command
time performs a different function.
Shows the directory tree of the current directory.
The TRUENAME command produces the full path name of drives, files, or directories.
MS-DOS can find files and directories given their names, without full path information, if the search object is on a path specified by the environment variable PATH. For example, if PATH includes C:\PROGRAMS, and file MYPROG.EXE is on this directory, then if
MYPROG is typed at the command prompt, the command processor will execute
TRUENAME command will expand a name in an abbreviated form which the command processor can recognise into its full form, and display the result. It can see through SUBST and JOIN to find the actual directory. This command 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. The Microsoft Windows command processors do not support this command.
Displays 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. TYPE can be used to concatenate files (type file1 file2 > file3); however this won't work for large files--use copy command instead.
Restores file previously deleted with del. By default all recoverable files in the working directory are restored; 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. Undeletion in Unix and Unix-like systems differs from filesystem to filesystem. For the ext2 filesystem, one example command is e2undel.
An internal DOS command, that reports the DOS version presently running, and since MS-DOS 5, whether DOS is loaded high. The corresponding command to report the Windows version is
winver. Values returned:
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 is a version of the copy command that can move files and directories from one location to another. Equivalent to the Unix command
cp when used with
|Wikibooks has a book on the topic of: Guide to Windows Commands|
There are several guides to DOS commands available that are licenced under the GNU Free Documentation License: