explain xkcd - User contributions [en]

2989: Physics Lab Thermostat

2024-09-26T13:18:39Z

172.70.91.63: /* Explanation */ Further tweaks.

{{comic
| number = 2989
| date = September 23, 2024
| title = Physics Lab Thermostat
| image = physics_lab_thermostat_2x.png
| imagesize = 264x296px
| noexpand = true
| titletext = Hopefully the HVAC people set it to only affect the AIR in the room.
}}

==Explanation==
{{incomplete|Created by ChatGPT, an actual bot, with the help of human copyeditors and critics as found on the talk page. Do NOT delete this tag too soon.}}

This comic is about a thermostat in a physics lab which, instead of directly controlling the ventilating air-conditioners or radiators, adjusts the {{w|Boltzmann constant}} in the immediate area. This value links our measure of temperature in gas against the energy that physics reveals courses through it. It is equal to 1.38×10−23 J/K, where J is {{w|joule}}s, a unit of energy, and K is {{w|kelvin}}, a unit of temperature. The dial shows different values for the constant, implying that it can be changed, which is absurd because the Boltzmann constant is a fundamental number that (as implied by the name) is supposed to stay the same throughout the universe. In reality, there is no known way to change the Boltzmann constant (and certainly not within an arbitrary zone), so the comic is making fun of the idea of a scientist casually adjusting a fixed law of physics as if it were something simple like room temperature.

If the Boltzmann constant could be changed, it would directly affect how we experience temperature. The constant determines how much energy particles have at a certain temperature. Adjusting the constant would disassociate the measurable temperature from the heat energy. What this practically means is hard to know, since it is not possible to test, but there is no reason to believe that this would act to heat (or cool) the room in any way. It may just require all thermometers to be recalibrated, unless it also effects the thresholds between kinetic energy and the physical states of matter (changes of state or thermal expansion).

The equivalent energy range relative to the actual Boltzmann constant might correspond to temperatures of 15°C (59°F) on the left, to 29°C (84°F) on the right (since raising the value of the constant decreases the temperature for a given energy level). The dial appears to be set to approximately 23°C (73°F), a not untypical desired room temperature within a fairly standard range of thermostat-style choice.  There have previously been control panels for properties of the universe in [[1620: Christmas Settings]] and [[1763: Catcalling]]. A thermometer including units compatible with this thermostat (after dividing by 2/3) is shown in [[2292: Thermometer]].

The title text builds on the absurdity of being able to adjust the Boltzmann constant. It suggests that if the constant could be changed, hopefully it would only affect the air in the room and not other substances. Imagining that this strange version of an HVAC ({{w|heating, ventilation, and air conditioning}}) system could contain such a change to ''just'' the room's air shows the ridiculousness of trying to isolate the effects of altering a universal constant.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A black circular dial is shown with a white indicator line at the upper right. The label above the dial, enclosed in a rectangular box, says:]
:Local Boltzmann Constant
:[The two extremes of the dial are labeled as follows, the first value on the left and the second value on the right:]
:1.418×10-23 J/K
:1.351×10-23 J/K
:[The indicator line is pointing to a position on the dial somewhere around 1.375×10-23 J/K (between the 12th and 13th large ticks clockwise out of 19 total).]
:[Caption below the panel:]
:Physics Lab Thermostat

{{comic discussion}}

[[Category:Physics]]

2960: Organ Meanings

2024-07-18T13:21:59Z

172.70.91.63: /* Explanation */

{{comic
| number = 2960
| date = July 17, 2024
| title = Organ Meanings
| image = organ_meanings_2x.png
| imagesize = 407x346px
| noexpand = true
| titletext = IMO the thymus is one of the coolest organs and we should really use it in metaphors more.
}}

==Explanation==
{{incomplete|Created by a BOT'S PINEAL GLAND - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This is a graph by [[Randall]] ranking how well he understands the function of certain human organs, compared to how much he understands {{w|metaphor}}s using them. 

One might expect understanding an organ's role and its use in metaphor to be strongly correlated, since the metaphors work by drawing a parallel to biological function. However, since our understanding of biological functions has evolved dramatically over time, and metaphorical language does not always keep up, the correspondence is often much looser. To complicate matters, many such anatomical metaphors vary from culture to culture, even though the biological functions remain largely consistent {{Citation needed}}.

The {{w|pineal gland}}, located in the center of the brain, was described as the “Seat of the Soul” by the dualist {{w|René Descartes}} in the 17th century. If this was what it was, the metaphors that might be derived from it would be pretty explicit. It was only in the mid-20th century that its real neuroendocrine (hormone-producing) biological role was grasped. Thus, the real meaning of the metaphor "the pineal gland of something" is uncertain, as is its actual function for the layman.

The {{w|thymus}}, highlighted in the title text, plays an important role in the immune system. It is not commonly used in metaphors,{{Citation needed}} but is perhaps ripe for use in ones describing such things as resilience, indomitability, and adaptability to changing circumstance, were more people to know what it was.

{| class="wikitable" style="margin:auto"
|-
! Organ !! Biological understanding !! Metaphor understanding !! Biological function !! Metaphor meaning(s)
|-
| {{w|Appendix_(anatomy)}} || 3% || 85% || Maintaining gut flora || Uselessness
|-
| {{w|Nerves}} || 40% || 90% || Sensing stimuli, and controlling muscles and organs || Courage; lack of courage; unsettledness
|-
| {{w|Spine}} || 50% || 80% || Holding other bones up || Courage; structural integrity
|-
| {{w|Heart}} || 80% || 90% || Circulation of blood || Emotion; feeling; sympathy; love; courage; resilience
|-
| {{w|Bones}} || 75% || 80% || Holding the skin up || Basic/underlying structure; something hidden; core; essence
|-
| {{w|Stomach}} || 70% || 65% || Repository for cake || Ability to tolerate unpleasant circumstances
|-
| {{w|Liver}} || 10% || 48% || Processing alcohol ||
|-
| {{w|Lungs}} || 60% || 52% || Oxygenation of blood; speaking || Loudness (e.g. of singing)
|-
| {{w|Spleen}} || 22% || 34% || Storing extra blood || Anger
|-
| {{w|Thymus}} || 10% || 13% || Training immune cells (T-Cells) ||
|-
| {{w|Kidneys}} || 47% || 19% || Filtering blood ||
|-
| {{w|Pineal gland}} || 2% || 2% || Produces melatonin ||
|-
| {{w|Tongue}} || 70% || 5% || Taste; chewing; speaking || Speaking; something long and extended
|}

==Transcript==
:[A graph is shown with X and Y-axis without arrow or ticks. To the left of the Y-axis and below the X-axis there are labels with an arrow pointing up from the top of the Y-axis label and an arrow pointing right above the X-axis label, just beneath the x-axis.]
:Y-axis: How well I understand what it means when used in metaphors
:X-axis: How well I understand its actual biological function

:[On the graph is a scatter plot with 13 labels. Each label is written inside a line that goes just around the words. There are most in the top right corner, but they are spread all over the graph. Here in approximate reading order from top left with indicating of where on the graph the words are located:]
:[Top left:]
:Appendix
:[Top middle:]
:Nerves
:Spine
:[Top right:]
:Heart
:Bones
:Stomach
:[Center left:]
:Liver
:Spleen
:[Center right:]
:Lungs
:[Bottom left:]
:Thymus
:Pineal gland
:[Bottom middle:]
:Kidneys
:[Bottom right:]
:Tongue

{{comic discussion}}

[[Category:Scatter plots]]
[[Category:Rankings]]
[[Category:Biology]]
[[Category:Language]]

Talk:525: I Know You're Listening

2024-06-21T23:34:17Z

172.70.91.63: That was a username's input, with easily discovered identity and timestamp (I don't understand what they're saying, however; doesn't make obvious sense).

Whether or not this is what the Citation request needs, http://en.wikipedia.org/wiki/Pascal%27s_Wager#Criticism would be helpful. Most people tend to go for the "What if it's the ''wrong'' god that you believe in?" counter to the wager. i.e. the parts of your religious observance that most please Zeus might well anger Odin greatly, or something similar for any two gods (pantheonic ''or'' sole Authority, this factor also being a major issue of choice) that you might care to compare between. This is mostly covered in the "Argument from inconsistent revelations" section of the above, it appears.

Personally my favoured counter-argument is that any sufficiently omniscient god worth his pillar-of-salt should ''know'' whether you are Wagering, and probably has a special area of Hell (or Tantarus) reserved for those that try to toady up to him by faking a belief (covered by the "Argument from inauthentic belief" section). I choose to believe that an honest non-believer might at least get a look-in at any middle-ground afterlife (regardless of their lack in belief of same), but I also don't have amy great reason to believe that this attitude is going to reward me, either.

(c.f. also the assumption that 'innocents', and people who have never been exposed to the Word Of GodTM are entitled to a free pass to some non-Hell level of afterlife, the punishment only applying after having been introduced to the whole Judeo-Christian system of post-death existence. On this basis, missionaries that go out and inform remote tribespeoples and oceanic islanders of the state of affairs are actually potentially making things a lot worse for their target audience than they ''would'' have been... Assuming that they're right in the first place.)

But note that, for every philosophical argument, there's an equal and opposite philosophical argument. I just plan on being good in the mortal world (where I know I will be rewarded, or at least regarded in a reasonably good light, if perhaps a bit of a doorstep) and if this doesn't help out when I hypothetically find myself at the Pearly Gates then I probably wouldn't have hit on the right form and combination of observances anyway so its not a wager that I could have reasonably 'won'.

This is, of course, way heavier an edit than I had intended, and I'm not suggesting that this is the best intepretation, just my own, and probably not worth a discussion over. [[Special:Contributions/31.111.87.233|31.111.87.233]] 09:28, 28 May 2013 (UTC)

(Forgot to say... non-deity eavesdroppers probably wouldn't have the omniscience, so go ahead and randomly profess your belief in them! [[Special:Contributions/31.111.87.233|31.111.87.233]] 09:30, 28 May 2013 (UTC))

:"Wouldn't have hit on the right form and combination of observances anyway"? Hmm. If only this hypothetical God had hypothetically given us some hypothetical information... like a book or something. That would have been helpful. --[[User:Jlc|Jlc]] ([[User talk:Jlc|talk]]) 02:11, 30 November 2018 (UTC)

:My best argument against pretending to believe something you doesn't is: do you really want to spend an ethernity with people whose belief you faked? For (extreme) example, if only Jehovah's witnesses go to heaven (and assuming you are not one), do you WANT to go there? Similarly, abstinents probably don't want to end in Valhalla. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 08:41, 5 June 2013 (UTC)

::This is a lot of unnecessary talk, even realized to be such by the one who wrote it. The explanation, as written, is fine without this extraneity. [[Special:Contributions/152.119.255.250|152.119.255.250]] 16:24, 30 September 2013 (UTC)
:::Since you did remove the incomplete tag I did add some more explains for Pascal's Wager. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 20:23, 30 September 2013 (UTC)

You get the record for longest expoundition of a title text.[[Special:Contributions/72.70.180.234|72.70.180.234]] 18:21, 19 October 2013 (UTC)

:Yes, check your e-mail. (Not you; him.)

[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 19:36, 30 January 2015 (UTC)

There is a [[explain_xkcd:Community_portal/Proposals#Merge_Cueball_.26_Rob|community portal discussion]] of what to call Cueball and what to do in case with more than one Cueball. I have added this comic to the new Category:Multiple Cueballs. Since there is only one Cueball that "talks" it is obvious to keep him listed as Cueball. Just made a note that the other guy also looks like Cueball. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:43, 15 March 2015 (UTC)

Cueball's calculation here is wrong. Yes, if there's nobody listening, he doesn't lose anything. But if there is, what happens when they think he's on to them could get unpleasant for him. {{unsigned ip|108.162.221.64}}

I'd do this on the internet but there's a good chance they actually are listening. Though they can't arrest commies for being commies, they can still watchlist them and monitor them closely, especially those who admit to plotting revolution. So yes, I know the government is listening, and the government knows I know they're listening. My only wonder is what are the consequences going to be? And how much faster will it be because I know they're listening?

Perhaps Cueball shouldn't be so quick as to say such... [[User:International Space Station|International Space Station]] ([[User talk:International Space Station|talk]]) 05:25, 22 April 2016 (UTC)

It is funny how embarrassing doing this actually feels, and how hard it seems to be to utter out. [[Special:Contributions/172.68.11.88|172.68.11.88]] 22:14, 1 September 2016 (UTC)

who else say I know your listening, alone. {{unsigned|Overlord of oddities|21:01, 21 January 2020}}
:I just flip the bird at presumed hidden cameras. If I actually thought someone were ''listening'', I'd play ''Why Can't We Be Friends''.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:06, 21 June 2024 (UTC)

Talk:2946: 1.2 Kilofives

2024-06-15T10:34:44Z

172.70.91.63:

Challenge: Come up with a way like this to say the comic number #2946. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:00, 15 June 2024 (UTC)
:How about 4.91 hectosixes? [[Special:Contributions/172.69.33.190|172.69.33.190]] 04:19, 15 June 2024 (UTC)
:A kibitwo, four decascore, four score and eighteen. Two octooctotwentythrees and two. A gross-score, three score and 6. [[User:Jordan Brown|Jordan Brown]] ([[User talk:Jordan Brown|talk]]) 05:00, 15 June 2024 (UTC)
:A semidozen tetrahectaenneacontahena. [[User:Xkcd machine guy|Xkcd machine guy]] ([[User talk:Xkcd machine guy|talk]]) 08:25, 15 June 2024 (UTC)
:A decapentagross minus a semiennea. [[User:Xkcd machine guy|Xkcd machine guy]] ([[User talk:Xkcd machine guy|talk]]) 10:10, 15 June 2024 (UTC)
Interestingly, four score and seven is exactly how you say 87 in French (quatre-vingt sept) and Basque (laurogeita zazpi). Both count on base 20. [[Special:Contributions/172.70.90.138|172.70.90.138]] 05:16, 15 June 2024 (UTC)

Fun fact: libqalculate and the "Qalculate"/"qalc" programs can just deal with the title text:
qalc "50milli score"
50 × (10^−3) × score = 1
But it fails on the main part, the best that works is:
qalc "1.2kilo 5"
1.2 × 10³ × 5 = 6000
"five" gets interpreted as Euler's number × imaginary unit × unknown "f" × unknown "v". On my old laptop, I must have some other configuration or maybe an old version, because there it gets interpreted as 0×i×e=0, so you can enter "five plus five" and get 0. Maybe another challenge would be to get arbitrary misleading results out from equations like this. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 05:59, 15 June 2024 (UTC)

Perhaps East Hills NY, but their "Welcome" boards don't mention population, https://www.google.co.uk/maps/@40.7805262,-73.632634,3a,15y,25.75h,92.88t/data=!3m6!1e1!3m4!1sf5guvv2tETuyn0f_lSFh7A!2e0!7i16384!8i8192?hl=en&coh=205409&entry=ttu so this might just be a random name that R. came up with[[User:Zeimusu|Zeimusu]] ([[User talk:Zeimusu|talk]]) 07:40, 15 June 2024 (UTC)

In the comic *fives* does not stand for the number five alone, but for five people. So using it with a prefix is more valid. Sebastian --[[Special:Contributions/172.68.110.4|172.68.110.4]] 10:15, 15 June 2024 (UTC)
: Five kilopeople would be valid.
: [[Special:Contributions/172.70.91.63|172.70.91.63]] 10:34, 15 June 2024 (UTC)

2878: Supernova

2024-01-10T09:17:32Z

172.70.91.63: /* Explanation */

{{comic
| number = 2878
| date = January 8, 2024
| title = Supernova
| image = supernova_2x.png
| imagesize = 348x227px
| noexpand = true
| titletext = They're a little cagey about exactly where the crossover point lies relative to the likelihood of devastating effects on the planet.
}}

==Explanation==
{{incomplete|Created by A CAGEY MOSTLY HAPPY ASTRONOMER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
A {{w|supernova}} occurs when a heavy star can no longer produce enough energy to fight its own gravity, e.g. because its fuel runs out (type II) or because it has accreted too much mass from a binary companion (type Ia). The collapsing mass leads to a violent explosion, one of the most interesting events for astronomers to observe and one that can be used to glean information about the universe.

At first glance, this graph appears to show the typical {{w|light curve}} of a {{w|type Ia supernova}}, constructed by plotting the brightness of the supernova as a function of time, with negative values indicating a logarithmic luminosity scale (below zero means a linear luminosity of less than the unit amount). In the event of a supernova, a star (which may previously have been unremarkable) becomes notably bright over a short period of time before trailing off again to leave a stellar remnant and expanding cloud of ejecta. Around the time of this comic's release new constraints on the expansion of the universe from the observation of type Ia supernovae were [https://news.fnal.gov/2024/01/final-supernova-results-from-dark-energy-survey-offer-unique-insights-into-the-expansion-of-the-universe/ published], which used the regular shape of their light curves to establish a distance scale.

However, upon closer inspection this comic purports to depict the relationship between the distance of supernovae from earth, and the consequent happiness of astronomers, which happens to take a similar form. There is a steep rise to a maximum in astronomer happiness. The further away the supernova occurs, the less detail can be learned from it, so the graph beyond the maximum happiness distance appears to show an asymptotic approach to less and less astronomer happiness. On the other hand, a {{w|near-earth supernova}} close enough to flood the Earth with a lethal amount of gamma and X-ray radiation might be considered ''too'' close. Its radiation could destroy life on Earth, or at least significantly harm the biosphere. Astronomers (and many others) would be really unhappy if that happened{{cn}}, shown as a sharp drop in happiness towards smaller distances and negative happiness values for a supernova that is too close. In fact, if a supernova were to instantly destroy Earth, or kill off all life on it, astronomers may no longer be able to be happy or unhappy (depending on your theological/spiritual feelings), so distance values close to zero have undefined astronomer happiness values.

Many astronomers watch and study the stars in the night sky, even those that don't change appreciably over human timescales, but observing and recording such a huge event would be interesting for many reasons. Humans can observe some supernovae with the naked eye, especially if they occur within {{w|Milky Way|our own galaxy}} and are clearly visible from Earth. A potential supernova in the news lately is {{w|Betelgeuse}}, a {{w|red giant}} star that is the left shoulder in the constellation Orion. About 430 light years from the Sun, it has been pulsating, dimming and brightening over exceedingly short time scales compared to the tens of millions of years such a big star is expected to burn. Betelgeuse should be far enough away from Earth that the inevitable explosion would be safe enough for life on Earth (although [https://www.skyatnightmagazine.com/space-science/earth-danger-betelgeuse-supernova some assessments] are not so sure), but it ''will'' outshine all other stars in the night sky, possibly competing with the Moon, and could even be visible during daytime. This would be a dream come true for many astronomers and something obvious to others interested in the night sky. In the first [[:Category:Stargazing | Stargazing]] comic, [[1644: Stargazing | 1644]], the wish that it goes supernova (in [[Randall|Randall's]] lifetime) is clearly expressed.

Since this ''should'' be safe for us, and since it would be a spectacle not seen for hundreds of years here on Earth, this would make astronomers very happy, not just from all they could learn, but also from all the increased interest in gazing at the sky with the 'new' star (and then seeing what happens to it next).
There are thought to be about three supernovae occurring per century within our own galaxy (most stars of which are much further away than Betelgeuse), and many other galaxies within which a supernova explosion can be detected. These remain useful to see, and are often studied as intensively as possible, but have decreasing amounts of thrill to them and are harder to notice/record in the early stages of the explosion (or immediately before, to add even more understanding).

The title text expands upon the point of "too close" supernovae, pointing out that astronomers are not quite clear or perhaps unwilling to admit how close they would like a supernova to be. If it were {{what if|73|close enough}} to severely impact the quality of human life, they would presumably not be happy, but the title text suggests that they might actually be willing to accept some trouble on Earth if they get to the see a supernova comparatively close by{{cn}}.

This is the second comic in a row that mentions exploding stars, after [[2877: Fever]], which like this comic is also a [[:Category:Charts|Charts comic]].

==Transcript==
:[A graph is shown where the axes are labeled and arrows are pointing upward above the Y axis label and to the right above the X axis label. There is a single line on the graph that peaks close to the Y axis, where it reaches close to the top of the drawn part of the Y axis. Then the line approaches the X axis asymptotically towards the far right. But closer to the Y axis, the peak line goes almost vertically down, and continues far below the "bottom of the chart", outside of the boundary of the graph that was only supposed to be above the X axis.]
:Y axis: How happy astronomers are
:X axis: How far away the new supernova is

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Astronomy]]

UniXKCD

2023-12-04T20:11:47Z

172.70.91.63: /* Undocumented commands */

{{incomplete|This page is missing almost all categories. Please run through all the commands and add any relevant category.}}

{{TOC}}On April Fools' Day in 2010, [[Randall Munroe|Randall]] altered [https://xkcd.com xkcd.com] to mimic a {{w|Unix}} command line interface. This interface is still available on [https://uni.xkcd.com uni.xkcd.com] and the source code is [https://github.com/chromakode/xkcdfools available on GitHub]. The comic [[721: Flatland]], which was released on March 31, 2010, was still up on April 1st, 2010, but had in itself nothing to do with the Unix interface. This Unix interface is thus in itself not one of Randall's [[:Category: April fools' comics|April fools' comics]]. The terminal only lists a few available commands, but most commands are undocumented.

==Documented commands==
* <code>next</code> shows the next comic. It shows the error "Time travel mode not enabled" on the last comic (see <code>enable time travel</code>).
* <code>prev</code> shows the previous comic.
* <code>first</code> shows the first comic.
* <code>last</code> shows the last comic.
* <code>display [number]</code> shows the comic with the specified number. (Trying to display comic [[404: Not Found|404]] will result in an endless loading attempt.)
* <code>random</code> shows a random comic.
* <code>ls</code> shows the content of the current directory.
* <code>cat [filename]</code> shows the content of the file, or "You're a kitty!" if [filename] is left blank.
* <code>cd [directory]</code> changes to the specified directory.

==Undocumented commands==
* <code>:(){:|:&};:</code> This command, otherwise known as a [https://askubuntu.com/questions/159491/why-did-the-command-make-my-system-lag-so-badly-i-had-to-reboot shell fork bomb] will make the terminal display the <code>[. . .]</code> loading text indefinitely, as though it crashed.
* <code>a/s/l</code> [https://www.urbandictionary.com/define.php?term=a%2Fs%2Fl A/S/L] is not a Unix command, but an acronym of Age/Sex/Location. The following replies are possible:
** "2/AMD64/Server Rack", answered as if the server replied.
** "328/M/Transylvania", answered by {{w|Dracula}}.
** "6/M/Battle School", answered by {{w|Ender Wiggin}} or another boy from battle school.
** "48/M/The White House", answered by {{w|Barack Obama}} or another male of the same age in the White House.
** "7/F/Rapture", answered by a {{w|Little_Sister_(BioShock)|Little Sister}} from {{w|BioShock}}.
** "Exactly your age/A gender you're attracted to/Far far away.", Requests for a/s/l are often not answered truthfully, but crafted to suit the one asking the question.
** "7,831/F/Lothlórien", answered by {{w|Galadriel}} or another elf.
** "42/M/FBI Field Office", answered by an FBI agent (referencing the old [https://tvtropes.org/pmwiki/pmwiki.php/Main/ThereAreNoGirlsOnTheInternet trope] that all girls on the internet are FBI agents impersonating them).
* <code>apt-get</code> replies "This APT has Super Cow Powers.". The <code>apt-get</code> command is part of the Debian package manager {{w|Advanced_Packaging_Tool|APT}}. This reply is one of the built-in Easter eggs.
* <code>apt-get moo</code> replies "Have you mooed today" with an ASCII cow.
* <code>asl</code> same as <code>a/s/l</code>.
* <code>bash</code> replies "You bash your head against the wall. It's not very effective.". {{w|Bash}} is a shell for POSIX-based systems.
* <code>buy stuff</code> same as <code>cd store</code>.
* <code>cat [number]/alt.txt</code> displays the title text of the specified comic.
* <code>cat</code> (without a filename, or an invalid one) will show "You're a kitty!", possibly referencing [[231: Cat Proximity]].
* <code>cheat</code> promotes the [https://store.xkcd.com/ xkcd store].
* <code>clear</code> clears the screen.
* <code>curl</code> creates an iframe to the URL specified
* <code>date</code> replies "March 32nd".
* <code>dir</code> same as <code>ls</code>.
* <code>echo</code> replies "Echo ... echo ... echo ...". The {{w|Echo_(command)|echo}} command is used to print text to the terminal.
* <code>ed</code> replies "You are not a diety ''[sic]''.". {{w|Ed_(text_editor)|ed}} is a very simple text editor. It is usually not considered very user-friendly (see also <code>vi</code> and <code>emacs</code>).
* <code>emacs</code> replies "You should use Vim.". References [[378: Real Programmers]].
* <code>enable time travel</code> replies "TARDIS error: Time Lord missing.". A {{w|Doctor Who}} reference. See also the <code>next</code> command.
* <code>exit</code> will end the terminal session.
* <code>find kitten</code> showed the {{w|robotfindskitten}} game (the link to the Flash version no longer works, but an HTML version is available [http://robotfindskitten.org/play/robotfindskitten/ here]).
* <code>find</code> replies "What do you want to find? Kitten would be nice.".
* <code>finger</code> replies "Mmmmmm...".
* <code>fuck</code> replies "I have a headache.".
* <code>goto [any]</code> shows comic [[292: goto]] and asks if you meant <code>display</code> instead.
* <code>go back</code> replies "You cannot go back."
* <code>go down</code> replies "On our first date?"
* <code>halp</code> same as <code>help</code>.
* <code> Hello Joshua </code> replies "How about a nice game of Global Thermonuclear War?". A reference to the {{w|WarGames}} movie.
* <code>hello</code> replies "Hello.". A second reply "Why hello there!" is coded, but it is never used.
* <code>help</code> says "That would be cheating!".
* <code>hi</code> replies "Hi.".
* <code>hint</code> randomly replies "We offer some nice polos.", "This terminal will remain available at xkcd.com/unixkcd/", "Use the source, Luke!" or "There are cheat codes.".
* <code>i read the source code</code> replies "<3".
* <code>irc [nick]</code> starts an {{w|IRC}} session on the xkcd channel on irc.foonetic.net.
* <code>kill</code> replies "Terminator deployed to 1984.". A reference to the {{w|The_Terminator|Terminator}} movie. In Bash, <code>kill</code> is used to end a process.
* <code>locate [filename]</code> is normally used to locate a file in a directory. It will give humorous results when searching for <code>ninja</code>, <code>keys</code>, <code>joke</code>, <code>problem</code> and <code>raptor</code>.
* <code>logout</code> same as <code>exit</code>.
* <code>lpr</code> replies "PC LOAD LETTER". {{w|Line_Printer_Daemon_protocol|lpr}} is a command to print documents. {{w|PC_LOAD_LETTER}} is a printer error.
* <code>make love</code> replies "I put on my robe and wizard hat.". A reference to this [http://www.albinoblacksheep.com/text/bloodninja roleplay chat transscript] (NSFW), also mentioned in [[442: xkcd Loves the Discovery Channel]]. <code>make love</code> is a standard Unix joke, because the reply is "make: don't know how to make love.".
* <code>make me a sandwich</code> behaves like [[149: Sandwich]].
* <code>man [command]</code> show unhelpful information about the command (only <code>last</code>, <code>help</code>, <code>next</code>, <code>cat</code> or no command are supported).
* <code>moo</code> replies "moo".
* <code>more</code> replies "Oh, yes! More! More!". The {{w|More_(command)|more}} command is used to paginate output.
* <code>nano</code> replies "Seriously? Why don't you just use Notepad.exe? Or MS Paint?". {{w|GNU_nano|Nano}} is another text editor for Unix systems (see <code>vi</code> and <code>emacs</code>).
* <code>ping</code> replies "There is another submarine three miles ahead, bearing 225, forty fathoms down.". The {{w|Ping_(networking_utility)|ping}} command is used to measure round trip times to a destination. The name does indeed originate from {{w|sonar}} technology.
* <code>pwd</code> replies "You are in a maze of twisty passages, all alike.". The {{w|pwd}} command prints the current working directory (see <code>look</code>).
* <code>poweroff</code> same as <code>shutdown</code>.
* <code>quit</code> same as <code>exit</code>.
* <code> Reddit [number]</code> shows the [https://www.reddit.com/ Reddit] voting bar for the specified comic (or xkcd when no number is specified).
* <code>rm [filename]</code> will "remove" a file, while <code>rm -r</code> will remove a directory. (<code>sudo rm -rf /</code> will break all commands until the page is reloaded.)
* <code>serenity</code> replies "You can't take the sky from me.". This is a line from the Balad of Serenity from the {{w|Firefly_(TV_series)|Firefly}} TV series.
* <code>shutdown</code> replies "Must be root.". See also <code>sudo poweroff</code>.
* <code>ssh</code> replies "ssh, this is a library.". {{w|Secure_Shell|ssh}} is the command to start a secure shell, but it also resembles the "{{w|Shh}}" sound.
* <code>su</code> replies "God mode activated. Remember, with great power comes great ... aw, screw it, go have fun.". The {{w|Su_(Unix)|su}} command is used to log in as an upper user, which gives you full and potentially dangerous access to the system. On some systems, "with great power comes great responsibility" is also part of a message that is printed the first time <code>sudo</code> is used.
* <code>sudo [command]</code> executes the command with {{w|Superuser|root}} privileges.
* <code>sudo apt-get dist-upgrade</code> Returns "You are already running [OS].".
* <code>sudo apt-get moo</code> replies "Have you mooed today?" (apt-get Easter egg).
* <code>sudo apt-get update</code> Refreshes the package list so the system knows which updates are available.
* <code>sudo apt-get upgrade</code> shows a link to [http://abetterbrowser.org/ A Better Browser] on Internet Explorer and Firefox (< v3). On all other browsers, it doesn't complain.
* <code>sudo make me a sandwich</code> behave like [[149: Sandwich]].
* <code>sudo !!</code> will sudo the last command.
* <code>sudo poweroff</code> will shutdown the system.
* <code>sudo reboot</code> will restart the system.
* <code>sudo restart</code> same as <code>sudo reboot</code>.
* <code>sudo shutdown</code> same as <code>sudo poweroff</code>.
* <code>sudo sudo</code> will print An internal error occurred: RangeError: Maximum call stack size exceeded in red text.
* <code>time travel</code> displays [[630: Time Travel]].
* <code>top</code> replies "It's up there --^". The {{w|Top_(software)|top}} command shows a table of processes. Here it is taken literally.
* <code>uname</code> replies "Illudium Q-36 Explosive Space Modulator". <code>uname</code> on Unix lists system information. The Illudium Q-36 Explosive Space Modulator is an explosive device created by Marvin the Martian in the {{w|Looney Tunes}} series.
* <code>unixkcd</code> opens a new terminal window.
* <code>use the force luke</code> replies "I believe you mean source.". A reference to the {{w|The_Force_(Star_Wars)|Force}} in the {{w|Star Wars}} franchise.
* <code>use the source luke</code> replies "I'm not luke, you're luke!", an old programmers' joke.
* <code>vi</code> reply "You should use emacs.". References [[378: Real Programmers]].
* <code>vim</code> same as <code>vi</code>.
* <code>wget [url]</code> shows the content of the specified url. The {{w|wget}} command on Unix will download the content and not show it.
* <code>who</code> replies "Doctor Who?". Another {{w|Doctor Who}} reference. The <code>who</code> command on Unix lists the logged-in users.
* <code> Whoami </code> replies "You are Richard Stallman.". The {{w|whoami}} command lists the name of the current user. Richard Stallman is the creator of the GNU project and the Free Software Foundation.
* <code>write [nick]</code> same as <code>irc</code>.
* <code>xkcd</code> replies "Yes?".
* <code>xyzzy</code> replies "Nothing happens.". {{w|Xyzzy_(computing)|xyzzy}} is a magic word, originally used in the game {{w|Colossal Cave Adventure}}.
* <code>your gay</code> replies "Keep your hands off it!".
* <code>!!</code> reruns the previous command after stating the command.

===Game commands===
* There are also some other commands borrowed from a {{w|Zork}} like {{w|Text-based game|text based adventure game}}.
* <code>look</code> describes your current surroundings.
* <code>go [direction]</code> moves you in the specified direction.
* <code>light lamp</code> lights your lamp.
* <code>sleep [seconds]</code> sleeps for the specified time. Without specifying, the nap is 5 seconds. You will be killed by a {{w|Grue (monster)|grue}} if you don't light your lamp when going south. Going wWestrepeatedly will list the refrain from the song {{w|Go West (song)|Go wWest}.

===Konami code===
[[File:Konami code.png|300px|thumb|The image used as the background after using the Konami code five times.]]
The terminal also responds to the {{w|Konami code}} Up, Up, Down, Down, Left, Right, Left, Right, B, A. Entering this code repeatedly will, in order:
# Transform all characters to uuppercase# Add a greatest shadow
# Add an orange text-shadow
# Shake the screen
# Add a background image of [[Richard Stallman]] from [[345: 1337: Part 5]].

[[Category:April fools' comics]]
[[Category:Comics featuring Richard Stallman]]