In
computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...
,
DELTREE
(short for ''delete tree'') is a
command line
A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...
command
Command may refer to:
Computing
* Command (computing), a statement in a computer language
* COMMAND.COM, the default operating system shell and command-line interpreter for DOS
* Command key, a modifier key on Apple Macintosh computer keyboards
* ...
in some
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
s,
SpartaDOS X
SpartaDOS X (or SpartaDOS 4.0) is a disk operating system for the Atari 8-bit family of computers that closely resembles MS-DOS. It was developed and sold by ICD, Inc. in 1987-1993, and many years later picked up by the third-party community S ...
and
FreeDOS
FreeDOS (formerly Free-DOS and PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running Legacy system, legacy software and supporting embedded system ...
that recursively deletes an entire subdirectory of files.
Overview
When
IBM and Microsoft introduced
PC DOS
PC or pc may refer to:
Arts and entertainment
* Player character or playable character, a fictional character controlled by a human player, usually in role-playing games or computer games
* ''Port Charles'', an American daytime TV soap opera
* ...
1.0 and
MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few ope ...
1.0, subdirectories were not yet supported. This state of affairs was remedied with the release of DOS 2.0, which introduced support for subdirectories and directory nesting; however, it had no built-in facility for deleting entire subdirectory trees.
Through the release of MS-DOS 5.0, removing nested subdirectories required removing all of the files in the lowest subdirectories, then removing the subdirectory itself, then repeating the process up the directory tree. By 1991 at least one competing product,
DR-DOS
DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with IBM PC DOS and MS-D ...
, had introduced a well-received utility that enabled recursive file deletion.
[ With the introduction of MS-DOS 6.0, Microsoft regained parity by adding the ]DELTREE
command.[
]DELTREE
was retained in Windows 9x
Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in subs ...
but was not shipped in Windows NT
Windows NT is a proprietary graphical operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems sc ...
family of operating systems. Instead, the rmdir
In computing, rmdir (or rd) is a command (computing), command which will remove an empty directory (file systems), directory on various operating systems.
Implementations
The command is available in Unix (e.g. macOS, Solaris (operating system), ...
(alias rd
) command removes a subdirectory along with all its files if the /S
command-line switch
A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive command
Command may refer to:
Computing
* Command (computing), a statement in a computer language
* COMMAND.COM, the default operating system ...
is given.
Implementations
In MS-DOS, PC DOS and Windows 9x, DELTREE
was implemented as an external command, with its functionality kept in a separate file outside of COMMAND.COM
COMMAND.COM is the default command-line interpreter for MS-DOS, Windows 95, Windows 98 and Windows Me. In the case of DOS, it is the default user interface as well. It has an additional role as the usual first program run after boot (init proc ...
.[ Normal operation prompted the user for verification that the specified directories were indeed intended to be removed, but this safeguard could be suppressed with a command-line option.][ Unlike most other commands that operated on the file system, multiple directories could be passed to the command at one time.][ An undocumented feature allowed the user to append a trailing "/" character to a directory name in order to preserve the directory but remove everything underneath it.][ In theory, deleted material could be recovered.][
]Datalight
Datalight was a privately held software company specializing in power failsafe and high performance software for preserving data integrity in embedded systems. The company was founded in 1983 by Roy Sherrill, and is headquartered in Bothell, Washi ...
ROM-DOS
Datalight was a privately held software company specializing in power failsafe and high performance software for preserving data integrity in embedded systems. The company was founded in 1983 by Roy Sherrill, and is headquartered in Bothell, Washi ...
also includes an implementation of the command.
The FreeDOS
FreeDOS (formerly Free-DOS and PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running Legacy system, legacy software and supporting embedded system ...
version was developed by Charles Dye and is licensed under the GPL v2
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general us ...
.
Syntax
The command-syntax is:
DELTREE YDRIVE:]ATH
Ath (; nl, Aat, ; pcd, Ât; wa, Ate) is a city and municipality of Wallonia located in the province of Hainaut, Belgium.
The municipality consists of the following districts: Arbre, Ath, Bouvignies, Ghislenghien, Gibecq, Houtaing, Irc ...
Use in malware and sabotage
DELTREE
was designed to ignore all file and directory attributes, such as ''hidden'', ''read-only'' and ''system''.[ The command was described as "potentially dangerous" and "capable of wiping out hundreds of files at a time".][ Combined with the PURGE command (which prevented data recovery), it became an example of a worst-case payload for ]malware
Malware (a portmanteau for ''malicious software'') is any software intentionally designed to cause disruption to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, depri ...
[ as well as figuring in one of the early computer sabotage trials.][
Contributing to the problem is the fact that MS-DOS and Windows 9x do not support ]discretionary access control
In computer security, discretionary access control (DAC) is a type of access control defined by the Trusted Computer System Evaluation Criteria (TCSEC) as a means of restricting access to objects based on the identity of subjects and/or groups to w ...
to mitigate this issue. The Windows NT family does. Furthermore, starting with Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...
, mandatory access control
In computer security, mandatory access control (MAC) refers to a type of access control by which the operating system or database constrains the ability of a ''subject'' or ''initiator'' to access or generally perform some sort of operation on a ...
and User Account Control
User Account Control (UAC) is a mandatory access control enforcement feature introduced with Microsoft's Windows Vista and Windows Server 2008 operating systems, with a more relaxed further mitigate the issue.
See also
*List of DOS commands
This article presents a list of commands used by DOS operating systems, especially as used on x86-based IBM PC compatibles (PCs). Other DOS operating systems are not part of the scope of this list.
In DOS, many standard system commands were pro ...
References
Further reading
*
*
External links
MS-DOS and Windows command line deltree command
{{Windows commands
External DOS commands
Windows administration
File deletion