# The history of the backslash **URL:** \ **Category:** Factual Questions\ **Created:** [May 6, 2013, 8:12pm UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646 "2013-05-06T20:12:52Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [May 6, 2013, 8:12pm UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/1 "2013-05-06T20:12:52Z")
I roll my eyes whenever a radio advertisement announcer reads a URL and keeps saying “backslash.” A guy at work uses a backslash in documents where everyone else would use a regular slash. I used to see it occasionally in ASCII art. The only place I’ve ever seen a backslash really needed is a DOS file path and used as an escape character in regexp (maybe a couple of other things, all computer related). Which got me to thinking–how long has the backslash been on a standard keyboard? Was it introduced to support DOS? Or does it have a more respectable background going back farther than that? Is there any usage of a backslash that predates the computer? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [May 6, 2013, 8:18pm UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/2 "2013-05-06T20:18:45Z")
First hit on Google tells me that it was introduced in 1961 to allow ASCII representation of ALGOL boolean operators. > **[Backslash](https://en.wikipedia.org/wiki/Backslash)** > > U+29F9 ⧹ BIG REVERSE SOLIDUS > The backslash \\ is a typographical mark used mainly in computing and mathematics. It is the mirror image of the common slash /. It is a relatively recent mark, first documented in the 1930s. It is sometimes called a hack, whack, escape (from C/UNIX), reverse slash, slosh, downwhack, backslant, backwhack, bash, reverse slant, reverse solidus, and reversed virgule. > As of November 2022\[update\], efforts to identify either the origin of this character or its purpose bef... ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [May 6, 2013, 9:29pm UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/3 "2013-05-06T21:29:22Z")
> [@gotpasswords](#): > > First hit on Google[URL=“[Backslash - Wikipedia](http://en.wikipedia.org/wiki/Backslash)”] Thanks. I have got to think up more imaginative questions :smack: ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [May 6, 2013, 11:12pm UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/4 "2013-05-06T23:12:28Z")
It was used in DOS, or so I have been given to understand, because in one of the standard OSes available at the time (ex. CP/M) the forward slash encoded a subset of the command, much as the hyphen does in Unix/Linux. Just as “ls -p” says, “List the contents of this directory, a screenful at a time,” the command “list /p” would mean the same thing in that language. ---
**Author:** ![Claverhouse](https://avatars.discourse-cdn.com/v4/letter/c/13edae/32.png) [@Claverhouse](https://boards.straightdope.com/u/Claverhouse)\ **Post date:** [May 7, 2013, 12:30am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/5 "2013-05-07T00:30:09Z")
Previous thread: **[URLs, Why a backslash ?](http://boards.straightdope.com/sdmb/showthread.php?t=632516)** ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [May 7, 2013, 12:55am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/6 "2013-05-07T00:55:37Z")
> [@gotpasswords](#): > > First hit on Google tells me that it was introduced in 1961 to allow ASCII representation of ALGOL boolean operators. > > [Backslash - Wikipedia](http://en.wikipedia.org/wiki/Backslash) On second thought, this is a chicken\egg problem. If it was introduced in ASCII, then was it not yet available on a keyboard? And you had to use numeric codes to enter the character? Or was it available on the keyboard but not yet in the ASCII set? The keyboard question isn’t answered in Wikipedia. ---
**Author:** ![LawMonkey](https://avatars.discourse-cdn.com/v4/letter/l/d6d6ee/32.png) [@LawMonkey](https://boards.straightdope.com/u/LawMonkey)\ **Post date:** [May 7, 2013, 1:12am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/7 "2013-05-07T01:12:46Z")
Curious–in the UK, is it a “backstroke”? ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [May 7, 2013, 1:47am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/8 "2013-05-07T01:47:21Z")
When I lived in Marina, CA, there was a web site design company down the road from my apartment. The big sign the company had with their own site listed, had “http:\” at the beginning. I always wondered if that hurt their business any. ---
**Author:** ![JWT\_Kottekoe](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@JWT\_Kottekoe](https://boards.straightdope.com/u/JWT_Kottekoe)\ **Post date:** [May 7, 2013, 2:10am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/9 "2013-05-07T02:10:52Z")
Which reminds me of the early internet joke ca. 1994: Q. What is O.J.'s internet address? A. Slash, slash, backslash, escape. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [May 7, 2013, 10:35am UTC](https://boards.straightdope.com/t/the-history-of-the-backslash/657646/10 "2013-05-07T10:35:08Z")
> [@LawMonkey](#): > > Curious–in the UK, is it a “backstroke”? No. We have a slash too.