Editing Dd (Unix) (section)

== History ==
In 1974, the {{code|dd}} command appeared as part of [[Version 5 Unix]]. According to [[Dennis Ritchie]], the name is an allusion to the [[Job Control Language#In-stream input|DD statement]] found in [[IBM]]'s [[Job Control Language]] (JCL),<ref>{{cite newsgroup |title=Re: origin of the UNIX dd command |first=Dennis |last=Ritchie |date=Feb 17, 2004 |newsgroup=alt.folklore.computers |message-id=c0s1he$1atuh9$1@ID-156882.news.uni-berlin.de |url=https://groups.google.com/forum/#!msg/alt.folklore.computers/HAWoZ8g-xYk/HDUVxwTVLKAJ |quote=dd was always named after JCL dd cards. |access-date=January 10, 2016 |archive-date=January 22, 2011 |archive-url=http://arquivo.pt/wayback/20110122130054/https://groups.google.com/forum/#!msg/alt.folklore.computers/HAWoZ8g-xYk/HDUVxwTVLKAJ |url-status=live }}</ref><ref name="jargon-dd">{{cite web | url=http://www.catb.org/jargon/html/D/dd.html | title=dd | first=Eric S. | last=Raymond | access-date=2008-02-19 | archive-date=2018-12-13 | archive-url=https://web.archive.org/web/20181213051044/https://www.catb.org/jargon/html/D/dd.html | url-status=live }}</ref> where ''DD'' is short for '''''d'''ata '''d'''efinition''.<ref>{{cite book |last1=Struble |first1=George |title=Assembler language programming: the IBM System/360 |date=1969 |publisher=Reading, Mass., Addison-Wesley Pub. Co |page=[https://archive.org/details/assemblerlanguag00stru/page/123/mode/2up?q=%22DD+statement%22+%22data+definition%22 123] |url=https://archive.org/details/assemblerlanguag00stru/page/122/mode/2up?q=%22DD+statement%22+%22data+definition%22}}</ref><ref>{{cite newsgroup |title=Re: etymology of the Unix "dd" command |first=Barry |last=Shein |date=Apr 22, 1990 |newsgroup=alt.folklore.computers |message-id=1990Apr22.191928.11180@world.std.com |url=https://groups.google.com/d/msg/alt.folklore.computers/K4uzWBugSPE/GwSgDUEU_3wJ |access-date=2016-07-14 |archive-date=2023-10-24 |archive-url=https://web.archive.org/web/20231024083144/https://groups.google.com/g/alt.folklore.computers/c/K4uzWBugSPE/m/GwSgDUEU_3wJ |url-status=live }}</ref> According to [[Douglas McIlroy]], {{code|dd}} was "originally intended for converting files between the [[ASCII]], little-endian, byte-stream world of [[Digital Equipment Corporation|DEC]] computers and the [[EBCDIC]], big-endian, blocked world of [[IBM]]"; thus, explaining the cultural context of its syntax.<ref>{{cite tech report |first1=M. D. |last1=McIlroy |author-link1=Doug McIlroy |year=1987 |url=http://www.cs.dartmouth.edu/~doug/reader.pdf |title=A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 |series=CSTR |number=139 |institution=Bell Labs}}</ref> [[Eric S. Raymond]] believes "the interface design was clearly a prank", due to the command's syntax resembling a JCL statement more than other Unix commands do.<ref name="jargon-dd"/>

In 1987, the {{code|dd}} command is specified in the [[X/Open]] Portability Guide issue 2 of 1987{{citation needed|date=April 2025}}. This is inherited by [[IEEE]] Std 1003.1-2008 ([[POSIX]]){{citation needed|date=April 2025}}, which is part of the [[Single UNIX Specification]].<ref name=SUS>{{man|1|dd|SUS}}</ref>

In 1990, David MacKenzie announced [[GNU]] fileutils (now part of [[coreutils]]) which includes the <code>dd</code> command;<ref>{{cite web |title=GNU file utilities release 1.0 |url=https://groups.google.com/g/gnu.utils.bug/c/CviP42X_hCY/m/YssXFn-JrX4J |website=groups.google.com |access-date=2023-04-28 |archive-date=2023-04-28 |archive-url=https://web.archive.org/web/20230428222649/https://groups.google.com/g/gnu.utils.bug/c/CviP42X_hCY/m/YssXFn-JrX4J |url-status=live }}</ref> it was written by Paul Rubin, David MacKenzie, and Stuart Kemp.<ref name=lin>{{man|1|dd|Linux}}</ref> Since 1991, Jim Meyering is its maintainer.<ref>{{cite web |title=GNU's Who |url=https://www.gnu.org/people/people.html#j |access-date=2023-04-28 |archive-date=2023-04-28 |archive-url=https://web.archive.org/web/20230428041041/http://www.gnu.org/people/people.html#j |url-status=live }}</ref>

In 1995, [[Plan 9 from Bell Labs|Plan 9 2nd edition]] was released with a {{code|dd}} command with a more traditional command-line option style than the JCL statement style.<ref>{{man|1|dd|Plan 9}}</ref>

Since at least 1999, [[UnxUtils]] has provided a [[Native (computing)|native]] implementation for the [[Microsoft Windows|Windows]] platform.<ref>{{cite web |title=Native Win32 ports of some GNU utilities |url=http://www.weihenstephan.de:80/~syring/win32/UnxUtils.html |date=15 August 2000|archive-url=https://web.archive.org/web/20000815200240/http://www.weihenstephan.de:80/~syring/win32/UnxUtils.html |archive-date=2000-08-15 }}</ref><ref>{{Cite web|url=http://unxutils.sourceforge.net/|title=Native Win32 ports of some GNU utilities|website=unxutils.sourceforge.net|access-date=2022-02-23|archive-date=2006-02-09|archive-url=https://web.archive.org/web/20060209022842/http://unxutils.sourceforge.net/|url-status=live}}</ref>