explain xkcd - User contributions [en]

3184: Funny Numbers

2025-12-24T19:36:04Z

Aasasd: /* Explanation */

{{comic
| number = 3184
| date = December 22, 2025
| title = Funny Numbers
| image = funny_numbers_2x.png
| imagesize = 360x453px
| noexpand = true
| titletext = In 1899, people were walking around shouting '23' at each other and laughing, and confused reporters were writing articles trying to figure out what it meant.
}}

==Explanation==
{{incomplete|This page was created by the square root of -2. Don't remove this notice too soon.}}
This comic refers to the recent meme {{w|6-7 meme|"6 7"}}, often accompanied by moving your hands up and down. While many people think that inscrutible obsession over certain numbers is a novel activity of the latest generation of kids, the comic points out that there's a long history of young people finding ways to have fun with certain numbers.

The numbers listed are:
{| class="wikitable sortable"
!Number!!Adopted?!!class="unsortable"|Explanation
|-
|data-sort-value="23"|23 (skidoo!)||data-sort-value="1899"|around 1899||The number relates to leaving quickly (a suggestion to go away), for indeterminate reasons.
{{w|23 skidoo|It was a death row prisoner's number}} in a then-new stage play based on ''A Tale of Two Cities'' by Charles Dickens. Soon after its coining, it was popularly combined with a term of similar use to become the phrase "{{w|23 skidoo}}".

23 gained some popularity again in the 1970s via the {{w|23 enigma}}, the suggestion that the number appears unusually often in significant contexts. This was first noticed by William S. Burroughs, and spread by Robert Anton Wilson and Robert Shea's book ''The Illuminatus! Trilogy'', and by ''Principia Discordia''.
|-
|42||1978||A number made popular by {{w|The Hitchhiker's Guide to the Galaxy}} a radio play, and book by Douglas Adams.
It is the undisputed {{w|Phrases from The Hitchhiker's Guide to the Galaxy#The Answer to the Ultimate Question of Life, the Universe, and Everything is 42|answer}} to the "ultimate question of life, the universe, and everything". Exactly what that question is, however, remains unknown and probably unknowable.
|-
|69||data-sort-value="1795"|1790s?||Refers to {{w|69 (sex position)|the sexual act of simultaneous oral gratification}}.
Described by the French as "soixante-neuf", i.e. "sixty-nine", at least as far back as the eighteenth century; though the concept itself is far older, and it would be very difficult to say when the mathematicians finally took note of 'young people' referencing it. One iconic mention of the number would be "69 dude" from {{w|Bill & Ted}}.
|-
|420||1971||This number (originally the time "4:20 pm", and later connected to April the 20th) has become {{w|420 (cannabis culture)|slang}} for smoking {{w|marijuana}}.
Randall previously made reference to this number in [[2153: Effects of High Altitude]].
|-
|1,337||data-sort-value="1985"|1980s?||"{{w|Leet}}-speak" is a form of textual obfuscation using an alternative orthography (various character substitutions and phonetic shifts) to 'spell' words.
"1337" is the usual way to represent the term "LEET" ("1" is commonly a lower-case "L", "3"s are often used as "E"s – see 58,008's calcuator-speak examples – and "7" closely resembles a "T"). This in turn, pronouncing "L" and "EET" separately, is the word "elite" (i.e. the self-description of the in-group who are using this system).
Randall has previously referred to 1337 in the [[Category:1337|1337]] series and in [[1337: Hack]].
|-
|58,008||data-sort-value="1975"|1970s?||The number "58008" {{w|Calculator spelling|spells}} "BOOBS" if you show it by seven-segment displays, like on many calculators, and turn the display upside down. There is also a longer version "5318008" which spells "BOOBIES".
This is not the only message you can say using calculators; for example, 0.7734 or 0.1134 'spells' "hELL'O"/”hello". Other examples include 71,077,345 ("Shell oil") and 59,611,345 ("Shell gas"). The inverted "3"/"E" relationship may have inspired the use of "1337" to represent "LEET".
|-
|data-sort-value="67"|6 7||2025||{{w|6-7 meme|This meme}} originated from the song "Doot Doot" by Skrilla and quickly became an in-crowd joke, together with hand actions, among many young people.
It was said to have [https://knowyourmeme.com/memes/67-meme been meaningless], though that hasn't stopped people from trying to assign a meaning to it.
|}

The title text claims that the media reaction to "23-skiddoo" around the turn of the 20th century (''one'' of the oldest terms, ''possibly'' the first noted by the mathematicians of that day) was very similar to the current media reaction to "6 7". This highlights a perennial historical cycle of the Young being confusing to the Old; with the Young growing up to become the Old and being confused by a new generation of Young.

Other cartoons featuring lists of symbolic numbers include [[487: Numerical Sex Positions]], while the issue of there being nothing actually new about seemingly contemporary developments is covered in comics like [[1227: The Pace of Modern Life]].

==Transcript==
:[A banner is hanging from the ceiling with a large line of text above a smaller one:]
:<big>Mathematical society</big>
:2025 meeting

:[Below the banner there are four people, three of them are standing close together to the left with Hairbun leftmost addressing Cueball and Megan who is looking at her. Ponytail is standing to the far right next to a whiteboard, and is using a marker to circle round the last of several items on the board.]
:Hairbun: Any other new developments from the year to cover before we wrap?
:Cueball: Oh, the teens picked a new funny number.
:Megan: Aww, I'm glad to hear they're still doing that.
:Ponytail: I'll add it to the list.

:[The board generally contains two columns of numbers, the first row having text after its number, thus across both columns. The last pair of digits is the new 'number' circled round by Ponytail. From top, in reading order, they are:]
:23 (skidoo!)
:42    1,337
:69    58,008
:420   6 7

{{comic discussion}}<noinclude>
[[Category: Comics featuring Hairbun]]
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring Megan]]
[[Category: Comics featuring Ponytail]]
[[Category: Math]]
[[Category: Language]]

Talk:2820: Inspiration

2023-08-26T03:24:17Z

Aasasd:

Here we see Cueball as W. B. Yeats, inventing the silver apples of the moon. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 03:24, 26 August 2023 (UTC)

Talk:2251: Alignment Chart Alignment Chart

2020-01-06T22:29:50Z

Aasasd:

OK, hope someone will now explain it after I created this page. I'm lost on this one ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:49, 6 January 2020 (UTC)

Arrgh, edit conflict! [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 11:55, 6 January 2020 (UTC)

I think the Omnispace Classifier is meant to be a horrific Frankenstein amalgamation of the other 8 kinds of chart. Theoretically it can "classify anything" since it can classify anything the other 8 can, but practically it would obviously be totally useless, or at least a lot less useful than just using the specific chart that works for the situation. [[User:Pureawes0me|Pureawes0me]] ([[User talk:Pureawes0me|talk]]) 12:09, 6 January 2020 (UTC)

I vaguely remember Randall to refer to the clay-sand diagram (or whatever it is called) as his all time favorite diagram on what-if somewhere. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 12:35, 6 January 2020 (UTC)
:You vaguely remember "Starsand" from https://what-if.xkcd.com/83/ with the quote "Fortunately, there's a wonderful chart by the US Geologic Survey that answers all these questions and more. For some reason, I find this chart very satisfying—it's like the erosion geology edition of the electromagnetic spectrum chart." directly applicabe to this chart[[User:Tier666|Tier666]] ([[User talk:Tier666|talk]]) 17:57, 6 January 2020 (UTC)

I fear any attempt to "explain" the CIE chromaticity diagram will devolve into arguments about why Randall chose it. I have found that folks outside the world of optics or neurooptical studies have a hard time understanding why the raw colors available in single wavelengths comprise that short curvy line inside the full colorspace. The way our brain processes the relative signal strengths from the different types of retinal cones is quite amazing. [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 12:57, 6 January 2020 (UTC)
:CGW I'm shocked! Surely you know that single-wavelengths are the curvy outer boundary while the inner curvy line shows the response to blackbody spectra. ;-) -Fred [[Special:Contributions/173.245.52.61|173.245.52.61]] 19:55, 6 January 2020 (UTC)
::Thanks for that; I was about to question the statement myself. All in all, I feel the current explanation of the chromaticity diagram doesn't really explain much, and seems unnecessarily biased to boot. I know just enough about chromaticity to think it's wrong but not enough to correct it. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 19:58, 6 January 2020 (UTC)
:::I agree that explanation isn't great, if it's not improved when I have free time tonight I'll take a stab at it. Or maybe CelloCGW will, since he IS an optics guru (which is why I had to raz him).[[Special:Contributions/173.245.52.61|173.245.52.61]] 20:13, 6 January 2020 (UTC)

@Fred - mea culpa. I should think before writing. Fortunately :-), the ratio of the colorspace to any 1-dimensional line's area is still infinite! [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 20:33, 6 January 2020 (UTC) .... now that someone did post some explanation of CIE, more comments. The current CIE spec may be paywalled, but it has changed little if at all over the last 40 or 50 years, so it's not all that hard to get the values. There are several sites (naturally I've lost the URLs) which provide algos to convert HSM to RGB to HSV and so on. See Wikipedia, https://law.resource.org/pub/us/cfr/ibr/003/cie.15.2004.tables.xls , and similar repositories [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 20:44, 6 January 2020 (UTC)

I'm only familiar with 4th and 5th edition, but should the "Good/neutral/evil:" axis eplanation be changed to "selfless deeds or selfish deeds"? Good and evil are highly subjective ("One person's 'freedom fighter' is another person's 'terrorist'.") but at least in 5e the axis is explained as risking/sacrificing yourself for the benefit of others (Good) vs. sacrificing others for your own benefit (Evil). Also, the explanation of the CN character may benefit from dividing which parts of the explanation are "chatoic" vs "neutral". Finally the "lacking rhyme or reason" part of chaotic is highly debated within D&D circles. There are certainly people who play that way, but there are also others who feel that chaotic characters have just as much motivation and goals as a lawful or neutral character just that part of their motivation is to act contrarily to Tradition/Authority. [[Special:Contributions/162.158.186.54|162.158.186.54]] 14:37, 6 January 2020 (UTC)

: It seems from this page that even nerds tend to interpret the alignment system by the ‘common sense’ meaning of the names instead of the detailed explanation. I once simply went through the Wikipedia article, which cited the second edition IIRC: ‘lawful’ means sticking to ''some'' code of conduct, whereas ‘chaotic’ is a pure opportunist or behaves randomly. ‘Good’ and ‘evil’ indeed mean selfless vs selfish deeds, but afaik in one of the official explanations ‘evil’ meant exercising authority over others—so all managers would be ‘evil’ automatically. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 16:42, 6 January 2020 (UTC)

I am not sure the phase diagram is for Water - that has nine solid phases. Surely it is merely a simple example.
[[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 16:52, 6 January 2020 (UTC)

As an interesting note, this comic's alt-text also ends with a period inside of a quote. This was discussed at length in the previous comic. [[User:Agrasin|Agrasin]] ([[User talk:Agrasin|talk]]) 16:52, 6 January 2020 (UTC)

I'm just upset that both a soil diagram and the QAPF were included, but not the TAS. Where's the love for extrusive igneous rocks? [[User:Mergelong|Mergelong]] ([[User talk:Mergelong|talk]]) 18:22, 6 January 2020 (UTC)

BTW, I offer my condolences and wish luck to the person who's going to make a transcript of this comic. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 22:28, 6 January 2020 (UTC)

Talk:2251: Alignment Chart Alignment Chart

2020-01-06T22:28:16Z

Aasasd:

OK, hope someone will now explain it after I created this page. I'm lost on this one ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:49, 6 January 2020 (UTC)

Arrgh, edit conflict! [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 11:55, 6 January 2020 (UTC)

I think the Omnispace Classifier is meant to be a horrific Frankenstein amalgamation of the other 8 kinds of chart. Theoretically it can "classify anything" since it can classify anything the other 8 can, but practically it would obviously be totally useless, or at least a lot less useful than just using the specific chart that works for the situation. [[User:Pureawes0me|Pureawes0me]] ([[User talk:Pureawes0me|talk]]) 12:09, 6 January 2020 (UTC)

I vaguely remember Randall to refer to the clay-sand diagram (or whatever it is called) as his all time favorite diagram on what-if somewhere. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 12:35, 6 January 2020 (UTC)
:You vaguely remember "Starsand" from https://what-if.xkcd.com/83/ with the quote "Fortunately, there's a wonderful chart by the US Geologic Survey that answers all these questions and more. For some reason, I find this chart very satisfying—it's like the erosion geology edition of the electromagnetic spectrum chart." directly applicabe to this chart[[User:Tier666|Tier666]] ([[User talk:Tier666|talk]]) 17:57, 6 January 2020 (UTC)

I fear any attempt to "explain" the CIE chromaticity diagram will devolve into arguments about why Randall chose it. I have found that folks outside the world of optics or neurooptical studies have a hard time understanding why the raw colors available in single wavelengths comprise that short curvy line inside the full colorspace. The way our brain processes the relative signal strengths from the different types of retinal cones is quite amazing. [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 12:57, 6 January 2020 (UTC)
:CGW I'm shocked! Surely you know that single-wavelengths are the curvy outer boundary while the inner curvy line shows the response to blackbody spectra. ;-) -Fred [[Special:Contributions/173.245.52.61|173.245.52.61]] 19:55, 6 January 2020 (UTC)
::Thanks for that; I was about to question the statement myself. All in all, I feel the current explanation of the chromaticity diagram doesn't really explain much, and seems unnecessarily biased to boot. I know just enough about chromaticity to think it's wrong but not enough to correct it. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 19:58, 6 January 2020 (UTC)
:::I agree that explanation isn't great, if it's not improved when I have free time tonight I'll take a stab at it. Or maybe CelloCGW will, since he IS an optics guru (which is why I had to raz him).[[Special:Contributions/173.245.52.61|173.245.52.61]] 20:13, 6 January 2020 (UTC)

@Fred - mea culpa. I should think before writing. Fortunately :-), the ratio of the colorspace to any 1-dimensional line's area is still infinite! [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 20:33, 6 January 2020 (UTC) .... now that someone did post some explanation of CIE, more comments. The current CIE spec may be paywalled, but it has changed little if at all over the last 40 or 50 years, so it's not all that hard to get the values. There are several sites (naturally I've lost the URLs) which provide algos to convert HSM to RGB to HSV and so on. See Wikipedia, https://law.resource.org/pub/us/cfr/ibr/003/cie.15.2004.tables.xls , and similar repositories [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 20:44, 6 January 2020 (UTC)

I'm only familiar with 4th and 5th edition, but should the "Good/neutral/evil:" axis eplanation be changed to "selfless deeds or selfish deeds"? Good and evil are highly subjective ("One person's 'freedom fighter' is another person's 'terrorist'.") but at least in 5e the axis is explained as risking/sacrificing yourself for the benefit of others (Good) vs. sacrificing others for your own benefit (Evil). Also, the explanation of the CN character may benefit from dividing which parts of the explanation are "chatoic" vs "neutral". Finally the "lacking rhyme or reason" part of chaotic is highly debated within D&D circles. There are certainly people who play that way, but there are also others who feel that chaotic characters have just as much motivation and goals as a lawful or neutral character just that part of their motivation is to act contrarily to Tradition/Authority. [[Special:Contributions/162.158.186.54|162.158.186.54]] 14:37, 6 January 2020 (UTC)

I am not sure the phase diagram is for Water - that has nine solid phases. Surely it is merely a simple example.
[[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 16:52, 6 January 2020 (UTC)
: It seems from this page that even nerds tend to interpret the alignment system by the ‘common sense’ meaning of the names instead of the detailed explanation. I once simply went through the Wikipedia article, which cited the second edition IIRC: ‘lawful’ means sticking to ''some'' code of conduct, whereas ‘chaotic’ is a pure opportunist or behaves randomly. ‘Good’ and ‘evil’ indeed mean selfless vs selfish deeds, but afaik in one of the official explanations ‘evil’ meant exercising authority over others—so all managers would be ‘evil’ automatically. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 16:42, 6 January 2020 (UTC)

As an interesting note, this comic's alt-text also ends with a period inside of a quote. This was discussed at length in the previous comic. [[User:Agrasin|Agrasin]] ([[User talk:Agrasin|talk]]) 16:52, 6 January 2020 (UTC)

I'm just upset that both a soil diagram and the QAPF were included, but not the TAS. Where's the love for extrusive igneous rocks? [[User:Mergelong|Mergelong]] ([[User talk:Mergelong|talk]]) 18:22, 6 January 2020 (UTC)

BTW, I offer my condolences and wish luck to the person who's going to make a transcript of this comic. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 22:28, 6 January 2020 (UTC)

Talk:2251: Alignment Chart Alignment Chart

2020-01-06T16:42:24Z

Aasasd:

Talk:2251: Alignment Chart Alignment Chart

2020-01-06T16:42:00Z

Aasasd:

936: Password Strength

2019-04-18T11:39:42Z

Aasasd: /* Explanation */ pretty sure a number itself ≠ the number of bits to represent it.

{{comic
| number = 936
| date = August 10, 2011
| title = Password Strength
| image = password strength.png
| titletext = To anyone who understands information theory and security and is in an infuriating argument with someone who does not (possibly involving mixed case), I sincerely apologize.
}}

==Explanation==
This comic says that a password such as "Tr0ub4dor&3" is bad because it is easy for password cracking software and hard for humans to remember, leading to insecure practices like writing the password down on a post-it attached to the monitor. On the other hand, a password such as "correcthorsebatterystaple" is hard for computers to guess due to having more entropy but quite easy for humans to remember.

In simple cases the {{w|Entropy (information theory)|entropy}} of a password is calculated as ''a^b'' where ''a'' is the number of allowed symbols and ''b'' is its length. A dictionary word (however long) has a password space of around 65000, i.e. 16 bits. A truly random string of length 11 (not like "Tr0ub4dor&3", but more like "J4I/tyJ&Acy") has 94^11 = 72.1 bits. However the comic shows that "Tr0ub4dor&3" has only 28 bits of entropy. Another way of selecting a password is to have 2048 "symbols" (common words) and select only 4 of those symbols. 2048^4 = 44 bits, much better than 28. Using such symbols was again visited in one of the tips in [[1820: Security Advice]].

It is absolutely true that people make passwords hard to remember because they think they are "safer", and it is certainly true that length, all other things being equal, tends to make for very strong passwords and this can confirmed by using [http://rumkin.com/tools/password/passchk.php rumkin.com's password strength checker]. Even if the individual characters are all limited to [a-z], the exponent implied in "we added another lowercase character, so multiply by 26 again" tends to dominate the results.

In addition to being easier to remember, long strings of lowercase characters are also easier to type on smartphones and {{w|Virtual keyboard|soft keyboards}}.

xkcd's password generation scheme requires the user to have a list of 2048 common words (log2(2048) = 11). For any attack we must assume that the attacker knows our password generation algorithm, but not the exact password. In this case the attacker knows the 2048 words, and knows that we selected 4 words, but not which words. The number of combinations of 4 words from this list of words is (211)4 = 244, i.e. 44 bits. For comparison, the [http://world.std.com/~reinhold/dicewarefaq.html#calculatingentropy entropy offered by Diceware's 7776 word list is 13 bits per word]. If the attacker doesn't know the algorithm used, and only knows that lowercase letters are selected, the "common words" password would take even longer to crack than depicted. 25 ''random'' lowercase characters would have [http://www.wolframalpha.com/input/?i=log2%2826^25%29 117 bits of entropy], vs 44 bits for the common words list.

;Example
Below there is a detailed example which shows how different rules of complexity work to generate a password with supposed 44 bits of entropy. The examples of expected passwords were generated in random.org.(*)

If ''n'' is the number of symbols and ''L'' is the length of the password, then ''L'' = 44 / log2(n).

{|class="wikitable"
!Symbols
!Number of symbols
!Minimum length
!colspan="2"|Examples of expected passwords
!Example of an actual password
!Actual bits of entropy
!Comment
|-
|a||26||9.3||mdniclapwz||jxtvesveiv||troubadorx||16+4.7 = 20.7||Extra letter to meet length requirement; log2(26) = 4.7
|-
|rowspan="2"|a 9
|rowspan="2"|36
|rowspan="2"|8.5
|rowspan="2"|qih7cbrmd
|rowspan="2"|ewpltiayq
|tr0ub4d0r||16+3=19||3 = common substitutions in the comic
|-
|troubador1||16+3.3=19.3||log2(10) = 3.3
|-
|a A||52||7.7||jAwwBYne||NeTvgcrq||Troubador||16+1=17||1 = caps? in the comic
|-
|a &||58||7.5||j.h?nv),||c/~/fg\:||troubador&||16+4=20||4 = punctuation in the comic
|-
|a A 9||62||7.3||cDe8CgAf||RONygLMi||Tr0ub4d0r||16+1+3=20||1 = caps?; 3 = common substitutions
|-
|a 9 &||68||7.2||_@~"#^.2||un$l|!f]||tr0ub4d0r&||16+3+4=23||3 = common substitutions; 4 = punctuation
|-
|a A 9 &||94||6.7||Re-:aRo||^$rV{3?||Tr0ub4d0r&||16+1+3+4=24||1 = caps?; 3 = common substitutions; 4 = punctuation
|-
|rowspan="2"|common words
|rowspan="2"|2048
|rowspan="2"|4
|rowspan="2"|reasonableretailsometimespossibly
|rowspan="2"|constantyieldspecifypriority||reasonableretailsometimespossibly||11×4=44||Go to random.org and select 4 random integers between 1 and 2048; then go to your list of common words
|-
|correcthorsebatterystaple
|0
|Because of this comic, this password has no entropy
|}

:a = lowercase letters
:A = uppercase letters
:9 = digits
:& = the 32 special characters in an American keyboard; Randall assumes only the 16 most common characters are used in practice (4 bits)

:(*) The use of random.org explains why <code>jAwwBYne</code> has two consecutive w's, why <code>Re-:aRo</code> has two R's, why <code>_@~"#^.2</code> has no letters, why <code>ewpltiayq</code> has no numbers, why "constant yield" is part of a password, etc. A human would have attempted at passwords that looked random.

==People who don't understand information theory and security==

The title text likely refers to the fact that this comic could cause people who understand information theory and agree with the message of the comic to get into an infuriating argument with people who do not — and disagree with the comic.

If you're confused, don't worry; you're in good company; even security "experts" don't understand the comic:

* Bruce Schneier thinks that dictionary attacks make this method "obsolete", despite the comic ''assuming'' perfect knowledge of the user's dictionary from the get-go. He advocates his own low-entropy "first letters of common plain English phrases" method instead: [https://www.schneier.com/blog/archives/2014/03/choosing_secure_1.html#!s!xkcd Schneier original article] and rebuttals: [http://robinmessage.com/2014/03/why-bruce-schneier-is-wrong-about-passwords/ 1] [http://security.stackexchange.com/a/62881/10616 2] [http://www.reddit.com/r/technology/comments/1yxgqo/bruce_schneier_on_choosing_a_secure_password/cfp2z9k 3] [http://www.reddit.com/r/YouShouldKnow/comments/232uch/ysk_how_to_properly_choose_a_secure_password_the/cgte7lp 4] [http://www.reddit.com/r/YouShouldKnow/comments/232uch/ysk_how_to_properly_choose_a_secure_password_the/cgszp62 5] [http://www.reddit.com/r/YouShouldKnow/comments/232uch/ysk_how_to_properly_choose_a_secure_password_the/cgt6ohq 6]
* Steve Gibson basically gets it, but calculates entropy incorrectly in order to promote his own method and upper-bound password-checking tool: [https://www.grc.com/sn/sn-313.htm#!s!math%20is%20wrong Steve Gibson Security Now transcript] and [https://subrabbit.wordpress.com/2011/08/26/how-much-entropy-in-that-password/ rebuttal]
* Computer security consultant Mark Burnett ''almost'' understands the comic, but then advocates adding numerals and other crud to make passphrases less memorable, missing the point: [https://web.archive.org/web/20150319220514/https://xato.net/passwords/analyzing-the-xkcd-comic/ Analyzing the XKCD Passphrase Comic]
* Ken Grady incorrectly thinks that user-selected sentences like "I have really bright children" have the same entropy as randomly-selected words: [https://www.hellersearch.com/blog/bid/141527/is-your-password-policy-stupid Is Your Password Policy Stupid?]
* Diogo Mónica doesn't understand that the words have to be truly random, not user-selected, like "let me in facebook": [https://diogomonica.com/posts/password-security-why-the-horse-battery-staple-is-not-correct/ Password Security: Why the horse battery staple is not correct]

Sigh.

==Transcript==
:The comic illustrates the relative strength of passwords assuming basic knowledge of the system used to generate them.
:A set of boxes is used to indicate how many bits of entropy a section of the password provides.
:The comic is laid out with 6 panels arranged in a 3x2 grid.
:On each row, the first panel explains the breakdown of a password, the second panel shows how long it would take for a computer to guess, and the third panel provides an example scene showing someone trying to remember the password.

:[The password "Tr0ub4dor&3" is shown in the center of the panel. A line from each annotation indicates the word section the comment applies to.]

:Uncommon (non-gibberish) base word
:[Highlighting the base word - 16 bits of entropy.]
:Caps?
:[Highlighting the first letter - 1 bit of entropy.]
:Common Substitutions
:[Highlighting the letters 'a' (substituted by '4') and both 'o's (the first of which is substituted by '0') - 3 bits of entropy.]
:Punctuation
:[Highlighting the symbol appended to the word - 4 bits of entropy.]
:Numeral
:[Highlighting the number appended to the word - 3 bits of entropy.]
:Order unknown
:[Highlighting the appended characters - 1 bit of entropy.]
:(You can add a few more bits to account for the fact that this is only one of a few common formats.)

:~28 bits of entropy
:228 = 3 days at 1000 guesses/sec
:(Plausible attack on a weak remote web service. Yes, cracking a stolen hash is faster, but it's not what the average user should worry about.)
:Difficulty to guess: Easy

:[Cueball stands scratching his head trying to remember the password.]
:Cueball: Was it trombone? No, Troubador. And one of the O's was a zero?
:Cueball: And there was some symbol...
:Difficulty to remember: Hard

:[The passphrase "correct horse battery staple" is shown in the center of the panel.]
:Four random common words {Each word has 11 bits of entropy.}

:~44 bits of entropy
:244 = 550 years at 1000 guesses/sec
:Difficulty to guess: Hard

:[Cueball is thinking, in his thought bubble a horse is standing to one side talking to an off-screen observer. An arrow points to a staple attached to the side of a battery.]
:Horse: That's a battery staple.
:Observer: Correct!
:Difficulty to remember: You've already memorized it

:Through 20 years of effort, we've successfully trained everyone to use passwords that are hard for humans to remember, but easy for computers to guess.

==External links==
*Some info was used from the highest voted answer given to the question of "how accurate is this XKCD comic" at StackExchange [http://security.stackexchange.com/questions/6095/xkcd-936-short-complex-password-or-long-dictionary-passphrase].
*Similarly, a question of "how right this comic is" was made at AskMetaFilter [http://ask.metafilter.com/193052/Oh-Randall-you-do-confound-me-so] and [[Randall]] responded [http://ask.metafilter.com/193052/Oh-Randall-you-do-confound-me-so#2779020 there].
*Also the Wikipedia article on '{{w|Passphrase}}' is useful.
*In case you missed it in the explanation, GRC's Steve Gibson has a fantastic page [https://www.grc.com/haystack.htm] about this (and may have prompted this comic, as his podcast [http://www.grc.com/sn/sn-303.htm] about this was posted the month before this comic).
* This comic inspired [http://blog.acolyer.org/2015/10/29/how-to-memorize-a-random-60-bit-string/ How to memorize a random 60-bit string] scientific paper (link is to the article about paper, wth paper itself linked)
* [https://github.com/dropbox/zxcvbn zxcvbn password strength estimator] thanks this comic for the inspiration in acknowledgements.
* CMU paper: [http://cups.cs.cmu.edu/soups/2012/proceedings/a7_Shay.pdf Correct horse battery staple: Exploring the usability of system-assigned passphrases]
* [http://research.microsoft.com/pubs/265143/Microsoft_Password_Guidance.pdf Microsoft Password Guidance] (page 8)
* [http://gizmodo.com/the-guy-who-invented-those-annoying-password-rules-now-1797643987 The Guy Who Invented Those Annoying Password Rules Now Regrets Wasting Your Time], August 8, 2017 (this comic is reproduced in the article).

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Math]]
[[Category:Computers]]
[[Category:Psychology]]

Talk:2132: Percentage Styles

2019-04-03T17:24:16Z

Aasasd:

The only proper style for Britain and the US is ‘%65’. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 16:20, 3 April 2019 (UTC)
:O RLY? [[Special:Contributions/108.162.241.52|108.162.241.52]] 16:37, 3 April 2019 (UTC)

:: Yes. You don't write ‘65$’, do you? British/US standards should be followed properly and consistently. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 17:19, 3 April 2019 (UTC)

::I've definitely seen %NN stated by style guides, but I almost never see anybody using it, because reading it aloud encourages saying it as "percent sixty-five". Oddly, people seem to have no trouble remembering to write $65 instead of 65$, despite the same "dollars sixty-five" vs "sixty-five dollars" vocalization issue. Perhaps it's because we often see things like $65.95 but %65.95 is used less often? Writing 65.95% is potentially ambiguous depending on how it's read out loud: "sixty-five point ninety-five percent" could definitely be misinterpreted very easily. 65.95$ is definitely not ideal, & $65.95¢ is somehow even worse. How about 65$.95¢? ''';S'''
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 17:08, 3 April 2019 (UTC)

----
There's also 65/100, 65:100, <math>\textstyle\frac{65}{100}</math>, sixtyfive-hundreth, 0.65, and point sixty-five. Benny. 16:41, 3 April 2019 (UTC)

There's also 650‰ [[Special:Contributions/172.69.33.41|172.69.33.41]] 16:52, 3 April 2019 (UTC)
:Wouldn't that be 650 hundredths? I've seen "and sixty-five ‰" a cheque before. [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 17:08, 3 April 2019 (UTC)

====
BTW, I can imagine the transcript of this one posing some challenge for screen readers. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 17:01, 3 April 2019 (UTC)

: On a second thought, I can also imagine people who use screen readers never hearing any difference between the writing styles listed in the comic. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 17:24, 3 April 2019 (UTC)

Talk:2132: Percentage Styles

2019-04-03T17:19:03Z

Aasasd:

Talk:2132: Percentage Styles

2019-04-03T17:01:41Z

Aasasd:

Talk:2132: Percentage Styles

2019-04-03T16:20:16Z

Aasasd:

Talk:1727: Number of Computers

2016-08-31T16:26:57Z

Aasasd:

Huh. Just noticed I missed a sentence at the beginning, but I'm too lazy to fix it. Could someone else rewrite my horrible draft? [[Special:Contributions/173.245.50.85|173.245.50.85]] 06:19, 31 August 2016 (UTC)
:I have done that now. ;-) And added a "few" extra details. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:52, 31 August 2016 (UTC)

The dotted line may also mean that the mission could possibly be extended, as happened to many NASA missions, in which case the destruction would occur later than currently planned.
Zetfr 15:22, 31 August 2016 (UTC)

There's a HAL9000 joke <s>in there</s> all over it. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 16:26, 31 August 2016 (UTC)

1692: Man Page

2016-06-10T14:44:47Z

Aasasd:

{{comic
| number = 1692
| date = June 10, 2016
| title = Man Page
| image = man_page.png
| titletext = For even more info, see blarbl(2)(3) and birb(3ahhaha I'm kidding, just Google it like a normal person.
}}

==Explanation==
{{incomplete|The two synopsis lines has not been explained, including the fact that there seems to be missing ending "]" and "}" in both lines (although taken together as one line they actually have the correct amount of brackets, but that would not make sense - I guess?) Someone seems to think the explanation for the copyright is lacking and has left a [text in square bracket] above that explanation. Please improve of delete that text if explanation now OK. Needs fact-checking of the table etc. and needs explanation of symbolic link}}

This comic shows a {{w|Unix}} manual page, i.e. a ''{{w|man page}}'' (hence the title), for a fictional program called "blerp". It details the command line options for this program, many of which are strange, annoying, or even impossible. These options are in alphabetical order (putting lower case before upper case and with an em-dash inserted between b and c the only exception to this order).

Unix man pages are meant to provide a brief reference on the usage of a command, not verbose and well-written explanations as you may find in manuals which is another common type of documentation. This fictional man page seems to exaggerate its crypticness, thus making fun of a common trait that many man pages have.

{{w|Command-line_interface#Command-line_option|Command-line options}}, also known as flags, are typed following a program name to change how the program runs. The following is an example usage.

<code>blerp -a -d -t -p "AVIGNON"</code>

This would run blerp in attack mode, outputting to DEBUG.EXE, with tumble dry, and with POPE set to AVIGNON. In most cases, any number of flags can be used in any order, and applicable flags can be followed by arguments (such as "AVIGNON" in this example).

For a walk through of all possible flags see the [[#Table of flags|table]] below.

Below the flags there are a ''see also'' list with other stupid program names. Apart from two more blerbs there is also blirb, blarb and blorb, with chapter references. The last blorp(501)(c)(3) is not a valid chapter reference for a man page, it is however a slightly covert reference to {{w|501(c)_organization|501(c)(3)}} which is an organization that is tax-exempt.

Then follows a bug report site. inaturalist.org is a site working to extend biological research, and http://www.inaturalist.org/taxa/47744-Hemiptera points to the same page as http://www.inaturalist.org/taxa/Hemiptera. {{w|Hemiptera}} is the order classifying True Bugs, making it the perfect place to report any new bug you have discovered...

[Copyright is a mishmash, "or best offer" is humorous, needs better explanation of individual parts.]

Finally there is a "{{w|copyright}}" line which references several variously open-source content licenses which is also a recurring theme on xkcd (see [[225: Open Source]]). For instance GPL references {{w|GNU General Public License}} and the (2) and (3+) refers to {{w|GNU_General_Public_License#Version_2|GPL 2}} and {{w|GNU_General_Public_License#Version_3|GPL 3 or higher}}. ''CC'' refers to {{w|creative commons}} where ''BY'' is the {{w|Creative_Commons_license#Types_of_licenses|type of license}}, ''5.0'' refers to the attribution and ''RV 41.0'' refers to revision 41.0. However there were no higher attribution than [https://creativecommons.org/licenses/by/4.0/legalcode 4.0] at the time of this comics release. xkcd is released under [http://creativecommons.org/licenses/by-nc/2.5/ CC BY-NC 2.5] as can be seen at the bottom of the {{xkcd}} homepage. A few comics have been released under the [[:Category:CC-BY-SA comics|CC-BY-SA license]] or [http://creativecommons.org/licenses/by-sa/3.0/ 3.0]. BSD refers to {{w|BSD licenses}} a [[:Category:BSD|recurring theme]] in xkcd . "LIKE GECKO" is a reference to a web browser user-agent string; modern user-agent strings include a lot of text designed{{Citation needed}} to let the browser pretend to be several different browsers/renderers, and "(like Gecko)" is the standard text for a browser that wants to be treated as if it were {{w|Gecko (software)|Gecko}} while admitting, if you look closely, that it isn't really Gecko. This copyright line, which includes a lot of mashed-together text that might appear to match any of several different licenses, resembles a user-agent string.

"OR BEST OFFER" is a reference to an auction where the person who bids the highest gets to buy the item. In context, it suggest the person who has the highest offer for blerp will be sold the rights to the program. Since the other licenses mentioned would allow for free usage without paying royalties, it would usually be pointless to buy the rights to the program.

In the title text there is a list with even more info, again with crazy names like blarbl and birb. Again there are page references, but for the last the person writing this stops writing the reference and begins to laugh at who ever still reads this man page and telling them that he is kidding and suggest that they ''just Google it like a normal person''. Seems like [[Randall]] does not believe much in man pages anymore... The writer of this text thus also stops finishing the brackets as the ending ")" for the last chapter is missing.

Man pages were part of the subject of [[293: RTFM]] and were mentioned in [[456: Cautionary]].

===Table of flags===
*There are 28 flags.
**Only these five letters are not used: l, m, w, x, z.
**j and k are used together as jk.
**The following seven capital letters are used: D, I, O, R, S, U, V.
***That makes it one capital letter for every lower case letter that is not used by itself.
**Finally the em dash "—" is used as the only non-letter character. Also the only that breaks the strict adiabatically sorting of the list, with lower case before upper case letters.
{| class="wikitable"
!Flag!!Description!!Explanation
|-
| -a||ATTACK MODE||This sounds like a command for a robot or something similar. Strange for a command line program. Possibly this is designed to break something?
|-
| -b||SUPPRESS BEES||Nonsensical option. This is a word play, meaning either to suppress {{w|Bee|Bees}} (the insects) or the letter '''B'''. This is also a possible {{w|Discworld}} reference, as the ''{{W|Hex_(Discworld)#Structure_and_technology|long-term storage}}'' of the only recurring computer in the series, ''{{w|Hex (Discworld)|Hex}}'', is composed of a beehive. (Note that the actual computer runs on ants.)
|-
| -—||FLAGS USE EM DASHES||Command line options (flags) typically use {{w|Hyphen|hyphens}} (short horizontal lines largely used within words). {{w|Dash#Em_dash|Em dashes}} (longer, with the same length as the letter "m") can't easily be typed into a command line interface, so switching flags from hyphens to em dashes is excessively difficult and nonsensical.
Also implies a paradox where if flags were to use em dashes, this flag itself would be invalid.
|-
| -c||COUNT NUMBER OF ARGUMENTS||Most likely not useful.
|-
| -d||PIPES OUTPUT TO DEBUG.EXE||{{w|DEBUG.EXE}} is the old 16-bit debugger that came with MS-DOS. On a Unix system it is much more likely that one would use the {{w|GNU Debugger}} (GDB). A debugger is usually called by calling the debugger with the program (or script) to be debugged as parameter.
{{w|Pipeline (Unix)|Piping}} in Unix means that the output of one program serves as input for another program.
|-
| -D||DEPRECATED||Many programs contain legacy options to avoid breaking scripts that use them. While the option should still work, the documentation is changed to say "deprecated" to discourage further use. Eventually such options usually get removed.
|-
| -e||EXECUTE SOMETHING||Vague. Also a possible pun on a kill-switch.
|-
| -f||FUN MODE||Strange and slightly ominous, given some of the other options. See under -O.
|-
| -g||USE GOOGLE||As an actual program flag, a bit hackjob-ish, but it is possible it is telling the user to use Google to find out what this tag does.
|-
| -h||CHECK WHETHER INPUT HALTS||Completely impossible, by the {{w|Halting problem}} which is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running or continue to run forever. {{w|Alan Turing}} proved in 1936 that a general algorithm to solve the halting problem for all possible program-input pairs cannot exist.
|-
| -i||IGNORE CASE (LOWER)||Usually, ignoring case means that a program will run without differentiating between upper- and lowercase. This flag suggests that blerp will run ignoring all the lowercase characters completely, or ignoring all the uppercase characters with the next flag "-I". Note that using this may make it ignore the difference for flags like -i and -I...
|-
| -I||IGNORE CASE (UPPER)||See above. Also possible that all text is converted to upper case, or that upper-case requirements only are ignored
|-
| -jk||KIDDING||A common acronym for [http://www.urbandictionary.com/define.php?term=jk Just Kidding], not a program flag. Also note that standard behavior of Unix command line options is that a single "-" can be followed by multiple one-letter options, making -jk equivalent to -j -k.
|-
| -n||BEHAVIOR NOT DEFINED||Possibly mathematically ominous? Otherwise useless.(Possible debug/unstable feature flag)
|-
| -o||OVERWRITE||Standard program flag, usually meaning that the program will overwrite a file rather than make a new one when data is output.May work strangely with -d.
|-
| -O||OPPOSITE DAY||Strange flag, possibly means that all other flags (or maybe even including this one!) have the opposite effects - if so, a lot of strange things would happen. (Especially with -b, -e, -f, -jk, -O...) Possible reference to the [https://www.youtube.com/watch?v=-zEGjlHZMiM Cyanide and Happiness Short: Opposite Day]
|-
| -p||SET TRUE POPE; ACCEPTS "ROME" OR "AVIGNON"||This refers to a {{w|Western_Schism|historical schism}} in the {{w|Catholic Church}}. In the 14th century, the Pope briefly ruled from Avignon, France, instead of Rome. After the Papacy was returned to Rome in 1377, the Church split (the so-called Western Schism) as not everyone accepted the move and the Pope who ordered it. This flag apparently allows the user to select a preferred Pope. There is actually a possible feature request here, as "PISA", a third Pope, should also be an option. It is the second time this week that Popes have been mentioned, last time was two comics before in [[1690: Time-Tracking Software]] regarding the Popes sexual activity.
|-
| -q||QUIET MODE; OUTPUT IS PRINTED TO STDOUT INSTEAD OF BEING SPOKEN ALOUD||In most cases, a program will output basic information to the console, and running it in quiet mode will make it run without outputting anything. Blerp, on the other hand, outputs information through audio, and the quiet flag causes it to run like a normal program. "STDOUT" is short for "standard output".
|-
| -r||RANDOMIZE ARGUMENTS||Pointless and possibly damaging.
|-
| -R||RUN RECURSIVELY ON <nowiki>http://*</nowiki>||The star (*) symbol is often used as a wildcard to match any string of characters. "<nowiki>http://*</nowiki>" suggests that blerp will be run on every (unsecured) webpage on the internet, or on each page recursively. What it might do in order to make this valid is also ominous.
|-
| -s||FOLLOW SYMBOLIC LINKS SYMBOLICALLY||[Needs explanation of symbolic links] Many commands offer an option to follow filesystem links, this option however seems to suggest that it will only politely pretend to do so.
|-
| -S||STEALTH MODE||Similar to -a, in that it sounds more like an option for some kind of robot.
|-
| -t||TUMBLE DRY||Perhaps useful for a program that runs on a clothes dryer. Refers to [https://img1.etsystatic.com/000/0/5254504/il_570xN.184726893.jpg directions like these]. Many clothing items are marked "do not tumble dry" in the care instructions, but this would be extremely difficult to make relevant to a program. Given the other flags, this may be less nonsensical than it would first appear..
|-
| -u||UTF-8 MODE; OTHERWISE DEFAULTS TO ANSEL||{{w|ANSEL}} is an old and obscure character encoding that predates ASCII. Using ANSEL as a default would be strange and largely incompatible with most modern systems. On the other hand, UTF-8 is rather standard. Similar in this regard to -q, blerp does something non-standard by default. The problem with using different modes (where the original was also UTF-8) is shown in the title text of [[1683: Digital Data]].
|-
| -U||UPDATE (DEFAULT: FACEBOOK)||Update usually refers to replacing an old software with a newer version. The default here suggests posting a status update to Facebook, sourcing an update form Facebook, or updating Facebook itself.
|-
| -v||VERBOSE; ALIAS TO find / -exec cat {}||Almost standard flag, in ordinary programs the opposite of -q - instead of silencing output, it makes it more specific, usually to help with debugging. Instead, this flag gets replaced with a command that prints the contents of all files in the filesystem tree. However, it will never complete, as certain device files never end (/dev/urandom contains random bytes). Note that the "find" command is missing <code>\;</code> and will not run, instead complaining <code>find: missing argument to `-exec'</code> .
|-
| -V||SET VERSION NUMBER||Many programs will have a flag to view the version number. This flag changes the version number instead.
|-
| -y||YIKES||[[wiktionary:yikes|yikes]] is an interjection which can express fear or empathy with unpleasant or undesirable circumstances. It is unclear how this would influence the program.
|}

==Transcript==
:[A terminal screen; the background is black and the text is white.]
:{| class="wikitable"
|style="background-color:black;"|
;NAME
:blerp

;SYNOPSIS
:blerp {[ OPTION | ARGS ]...[ ARGS ... -f [FLAGS] ...}
:blerp {... DIRECTORY ... URL | BLERP} OPTIONS ] -{}

;DESCRIPTION
:blerp FILTERS LOCAL OR REMOTE FILES OR RESOURCES USING PATTERNS DEFINED BY ARGUMENTS AND ENVIRONMENT VARIABLES. THIS BEHAVIOR CAN BE ALTERED BY VARIOUS FLAGS.

;OPTIONS
:{|
! scope="row" | -a
| ATTACK MODE
|-
! scope="row" | -b
| SUPPRESS BEES
|-
! scope="row" | -—
| FLAGS USE EM DASHES
|-
! scope="row" | -c
| COUNT NUMBER OF ARGUMENTS
|-
! scope="row" | -d
| PIPES OUTPUT TO DEBUG.EXE
|-
! scope="row" | -D
| DEPRECATED
|-
! scope="row" | -e
| EXECUTE SOMETHING
|-
! scope="row" | -f
| FUN MODE
|-
! scope="row" | -g
| USE GOOGLE
|-
! scope="row" | -h
| CHECK WHETHER INPUT HALTS
|-
! scope="row" | -i
| IGNORE CASE (LOWER)
|-
! scope="row" | -I
| IGNORE CASE (UPPER)
|-
! scope="row" | -jk
| KIDDING
|-
! scope="row" | -n
| BEHAVIOR NOT DEFINED
|-
! scope="row" | -o
| OVERWRITE
|-
! scope="row" | -O
| OPPOSITE DAY
|-
! scope="row" | -p
| SET TRUE POPE; ACCEPTS "ROME" OR "AVIGNON"
|-
! scope="row" | -q
| QUIET MODE; OUTPUT IS PRINTED TO STDOUT INSTEAD OF BEING SPOKEN ALOUD
|-
! scope="row" | -r
| RANDOMIZE ARGUMENTS
|-
! scope="row" | -R
| RUN RECURSIVELY ON <nowiki>http://*</nowiki>
|-
! scope="row" | -s
| FOLLOW SYMBOLIC LINKS SYMBOLICALLY
|-
! scope="row" | -S
| STEALTH MODE
|-
! scope="row" | -t
| TUMBLE DRY
|-
! scope="row" | -u
| UTF-8 MODE; OTHERWISE DEFAULTS TO ANSEL
|-
! scope="row" | -U
| UPDATE (DEFAULT: FACEBOOK)
|-
! scope="row" | -v
| VERBOSE; ALIAS TO find / -exec cat {}
|-
! scope="row" | -V
| SET VERSION NUMBER
|-
! scope="row" | -y
| YIKES
|}

;SEE ALSO
:blerp(1), blerp(3), blirb(8), blarb(51) blorp(501)(c)(3)

;BUG REPORTS
:<nowiki>http://www.inaturalist.org/taxa/47744-Hemiptera</nowiki>

;COPYRIGHT
:GPL(2)(3+) CC-BY/5.0 RV 41.0 LIKE GECKO/BSD 4(2) OR BEST OFFER

|}

{{comic discussion}}

[[Category:Programming]]
[[Category:Computers]]
[[Category:BSD]]
[[Category:Animals]]

Talk:1638: Backslashes

2016-02-03T10:13:54Z

Aasasd:

It should be noted that this also occurs in almost every programming language where "\" is the escape character. i.e.
print("Hello")
> Hello
print("\"Hello\"")
> "Hello"
print("\\Hello\\")
> \Hello\
Oh, and by the way, isn't this the third comic to mention "Ba'al, the Soul Eater"? Maybe we should start a category. (Others are [http://www.explainxkcd.com/wiki/index.php/1246:_Pale_Blue_Dot 1246] (title text) and [http://www.explainxkcd.com/wiki/index.php/1419:_On_the_Phone 1419].)
[[Special:Contributions/173.245.54.29|173.245.54.29]] 06:14, 3 February 2016 (UTC)
:[[:Category:Ba'al|Did that]] before seeing you comment, so yes I agree. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:47, 3 February 2016 (UTC)

;I don't think the regex is invalid

According to <tt>man grep</tt> you need to specify the <tt>-E</tt> option to use extended regex; without it unescaped parentheses are not interpreted, so they don't need to match.

My - very wild - guess is that it was the command he used to find the line with the most special characters, but I am not confident enough to edit the article (if someone can confirm?). {{unsigned ip|141.101.66.83}}

If it was supposed to do that, it doesn't work. Running it on my bash history matches no lines, and I have lots of special characters in there [[Special:Contributions/197.234.242.243|197.234.242.243]] 07:12, 3 February 2016 (UTC)

Explain it to me like I'm dumb. What is this comic going on about? I think the explanation needs more examples like that hello, above, because that's almost understandable. --[[Special:Contributions/198.41.238.231|198.41.238.231]] 07:47, 3 February 2016 (UTC)
:I agree. But I cannot help either.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:51, 3 February 2016 (UTC)

This is the third time Randall has mentioned Ba'al the Soul Eater xD [[User:International Space Station|International Space Station]] ([[User talk:International Space Station|talk]]) 08:26, 3 February 2016 (UTC)
:Yes, that was already mentioned a few hours before you comment, see the first comment. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:51, 3 February 2016 (UTC)

After passing the regex through bash, you get <nowiki>\\[[(].*\\[\])][^)\]]*$</nowiki> That is, the literal character \, followed by [ or (, followed by any number of any characters, followed by \, followed by ] or ), followed by any number of characters that aren't ) or ], until the end of the line. [[Special:Contributions/108.162.216.44|108.162.216.44]] 08:33, 3 February 2016 (UTC)
:It sounds like you know what you are talking about. Anyone who can explain it good enough for the explanation, and correct the explanation of the title text if it is wrong to say that it would not work. I have added this as the reason for incomplete. But maybe also examples are needed for people with not programming skills/knowledge. We also enjoy xkcd ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:51, 3 February 2016 (UTC)
For fun:
cat ~/.bash_history | xargs -d "\n" -n 1 -I {} bash -c 'chars="$(echo "$1" | grep -o "[a-zA-Z0-9 ]" | wc -l)"; echo "$(( 100 - $(( $chars * 100 / ${#1} )) )) $1"' _ {} | sort -nrk 1 | less

Outputs your bash_history, ordered by relative gibberishness. This was copied by hand from desktop to mobile, might well have a few typos.--[[Special:Contributions/162.158.90.208|162.158.90.208]] 10:04, 3 February 2016 (UTC)

The problem in the comic is not with regexes per se but with situations when the entered text or expression passes through several interpreters, like bash -> grep/sed/awk, or program text -> external shell command. In such cases, you have to escape backslashes for each program in the sequence, and it gets worse if you have 'real' backslashes in the final text that you're processing with the utilities (Windows' file paths, for example). See https://en.wikipedia.org/wiki/Leaning_toothpick_syndrome.
Feel free to lift this to the explanation page, since I'm not good at longer and more careful explanations than this one.
Also, gotta notice that Feedly stripped paired backslashes in the title text (probably passed it through some 'interpreter' embedded in its scripts). [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 10:13, 3 February 2016 (UTC)

Talk:1564: Every Seven Seconds

2015-08-18T08:01:47Z

Aasasd:

Not true, but where did it come from? http://www.snopes.com/science/stats/thinksex.asp [[Special:Contributions/108.162.249.155|108.162.249.155]] 11:55, 14 August 2015 (UTC)

Sorry SteveMB, but I don't think we need to tell the joke again in order to explain it. [http://www.explainxkcd.com/wiki/index.php?title=1564%3A_Every_Seven_Seconds&diff=99634&oldid=99632]. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 12:58, 14 August 2015 (UTC)
:While this may be true, I actually found the first explanation to be much more valuable and insightful than this two mini-paragraph drab. The author of this new version doesn't even make the distinction between thinking about sex every seven seconds and thinking about having sex every seven seconds. [[User:Jarod997|Jarod997]] ([[User talk:Jarod997|talk]]) 13:04, 14 August 2015 (UTC)
::Agreed. Although the first explanation wasn't perfect, it was better than the replacement. The title text explanation in this version is missing the point. We should look to re-incorporate some/most of the original explanation. --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 13:08, 14 August 2015 (UTC)
:::The first explanation says nothing about sociologists. I added that when I realized I had missed it, and Pudder realized it was missing when he read my terse explanation, but not when he read the verbose explanation that SteveMB wrote. Note also that we always explain the difficult terms first ''(seven seconds'' in this case). The original "explanation" actually is a retelling of the joke. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 13:29, 14 August 2015 (UTC)
:::: The sociologist joke explanation was missing, I noted that when I added the incomplete tag, not because of your comment. In adding your explanation you wiped a lot of existing explanation, perhaps you believe it isn't necessary, but its frustrating because your explanation is frankly no better. In particular, your version of the title text explanation is simply missing the point. (The point that was previously explained!) --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 13:34, 14 August 2015 (UTC)

The title text is misunderstood. It's about <<sex in every 7 seconds>> he thinks, how unplausible ''that'' would be. [[Special:Contributions/141.101.97.202|141.101.97.202]] 13:39, 14 August 2015 (UTC)

You all may be right about the title text. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 13:44, 14 August 2015 (UTC)

Please compare
{|class=wikitable
!Verbose!!Terse
|-
|Cueball is raising skeptical objections to something, first dismissing the notion out of hand ("There's no way that's true."), then noting that it would cause obvious and unmistakable effects that are not, in fact, observed ("It would interfere with basic cognition."), then deciding that the idea is tied to an absurd worldview ("Such a ridiculous view of masculinity."), then raising the question of how anyone would even know whether or not the claim is true ("How would you even ''study'' that?"). These objections, particularly the second and third one, and the title "Every Seven Seconds" suggest that the statement Cueball is dismissing is the oft-stated assertion that men think about sex every seven seconds.
 
The title text confirms this inference...
|In this joke Cueball seems to be raising skeptical objections to this myth ''[the seven-seconds myth]''. The title of the comic (Every seven seconds) hints strongly about it, and all comments lead us to believe that Cueball wants to debunk the myth. However in the punchline we learn that Cueball is a sociologist who disbelieves in a team of his colleagues actually studying such a difficult subject (the same objection raised in BBC's reference).
|-
|}
The first explanation says nothing about sociologists, and falls into the trap of believing that the joke is simply about debunking an urban myth. I fell into that trap myself, but soon I realized my mistake. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 13:51, 14 August 2015 (UTC)

I think the Explanation is missing the obvious connotations to this joke. For example, ''"Cueball is a sociologist who disbelieves in a team of his colleagues actually studying such a difficult subject"'' what does this even mean? The explanation is that sociologists (implied: all sociologists) think about the urban myth every seven seconds and the thought bubbles in the comic are their possible thoughts. Each thought bubble would take place predictably every seven seconds. The setup is that thinking about sex every seven seconds would be dysfunctional and unproductive in addition to making working, social interactions, etc... nearly impossible as explained by the sociologists thoughts. The punch line is that thinking about how ridiculous it is to think about sex every seven seconds is just as dysfunctional and unproductive even if the thought time is spent refuting the original notion as understood in third person.--[[User:R0hrshach|R0hrshach]] ([[User talk:R0hrshach|talk]]) 16:27, 14 August 2015 (UTC)
:Agreed, nowhere does the comic imply that Cueball is thinking about any "team". His thoughts are about how ridiculous the fact is. [[Special:Contributions/162.158.255.156|162.158.255.156]] 04:54, 15 August 2015 (UTC)

;Plausibility of every seven seconds

Cueball is thinking about it from a statician's standpoint (units have a tendency to be within a couple orders of magnitude at furthest). However, it should be pointed out that from a math & physics perspective, there's nothing irrational about the comment at all. Afterall, a person can assume that it's an average. (Afterall, it would be difficult for a counterpoint of un-concious un-dreaming men to be thinking about sex every seven seconds.) "Once" leaves a lot of wiggle room as "once" is not coupled with any particular unit of measurement. Once could be one second, it could be seven seconds, it could be a millionth of a second.

All a man (or woman) would have to do is think about sex once in their entire lifespan, and that moment would just have to be divided by 1/7th of all of the seconds in their life combined, and you have your average figure.

So, considering that interpretation, I would like to present my mathmatical observation to provide a more complete picture of men thinking of sex every seven seconds...

Women think about sex once every 3 seconds.

[[Special:Contributions/108.162.237.191|108.162.237.191]] 07:10, 15 August 2015 (UTC)

:If you think about it from a math & physics perspective, you are actually showing how ridiculously unsubstantial that "once per 7 seconds per average" statement is. Puting aside the "how do you count that" problem, the BBC approach of counting how many times per day people think about sex makes more sense. For example, if you are actually HAVING sex, you are likely to think about it for (significantly) longer than 7 seconds without interruption. (Jokes about premature ejaculation and about women thinking what to make for dinner while having sex notwithstanding.) -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 12:01, 15 August 2015 (UTC)
Having sex an average of an hour each day and defining "thinking about" as to cover each moment would give a rate of once every twenty-four seconds. Note that if ones definition of "thinking about" allows for multiple thoughts in parallel (e.g. while dancing at a concert, think of the beat, the melody, your partners, the crowd, your current/anticipated dance moves, the lyrics, sex AND drugs) would increase the feasibility of such high ratios.

Measuring frequency of sexual thoughts by giving a click counter for subjects to press when for each direct and indirect thought about sex can approach 100%, if the subject thinks about sex by considering whether to push the button, because each button press would correspond to another thought to be tallied.
[[User:Comet|Comet]] ([[User talk:Comet|talk]]) 20:27, 15 August 2015 (UTC)

You are standing on a garden path. To the left, the complex houses married and single soldiers and their families. To the right, the horse raced past the barn fell. The old man the boat. The government plans to raise taxes were defeated. [[User:Aasasd|Aasasd]] ([[User talk:Aasasd|talk]]) 08:01, 18 August 2015 (UTC)