Talk:1168: tar

Explain xkcd: It's 'cause you're dumb.
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I thought the title text would be "tar --help" 06:59, 1 February 2013 (UTC)

The comic is about the difficulty of the tar program options.

Even if his life depended on it and after years of usage, Bob/Randall could not come up with the right parameters without looking them up. So a situation is shown, where Bob's life depends on coming up with the right parameters:

  • It shows an atomic warhead
  • It has a user interface, which requests any valid tar command
  • If it is not entered on the first try within 10s, the bomb is not disarmed and potentially explodes on the spot

Randall has come up with a situation, where the unix guy Bob can be the hero by knowing tar parameters. This is a pipe dream of a geek; nobody cares IRL, if you know tar parameters on the first try.

It is hilarious, that

  • the bomb says in full detail the rules including that you should not cheat and it probably has no means to check whether you cheated. This is no game, but feels like one. In war and love every means is allowed - even cheating; it would also be self-defense for disarming the bomb; Bob and his colleagues are not even considering to cheat.
  • the user has root access to the bomb, shown by the bomb as ~#, the tilde is the home directory, the # signifies super-user rights; even if the available programs prevent the bomb from being shutdown or disabled by a nonintended way, normally no root access is given for users of linux devices during normal usage; and disarming the bomb with official rules is normal usage of a bomb; a root prompt should not be necessary, if the bomb software is designed and configured well; possibly the unix prompt is a simulation for entering an answer
  • Bob shurely needs more than 10s to come. So the bomb will have announced that questions, which require unix knowledge will follow - or has already asked other Unix questions; perhaps after 10s without entering anything a new question comes up
  • this bomb can be disarmed with "common knowledge"

Small notes:

  • The screen looks to be really grayscale (esp. the inverted "TEN") - not just because of the comic; it has at least 3 colors (black, white, tar gray); it could be that the "TEN" is updated dynamically and is thus inverted
  • The comic is quite black: The screen and the bomb; Randall seldomly uses solid black areas; the bomb is a gloomy topic so it is black like "tar" (pun)

Sebastian -- 07:24, 1 February 2013 (UTC)

I think there is a visual double pun in this strip: the bomb disarmed by a tar command is a reference to the tarbombs, but it also looks like the Tsar Bomb(a). --Koveras (talk) 08:24, 1 February 2013 (UTC)

I don’t think it looks like Tsar Bomba. If anything, it is much more similar to Fat Man. --Mormegil (talk) 08:38, 1 February 2013 (UTC)
Yeah, but "Fat Man" doesn't sound like "tarbomb". --Koveras (talk) 10:48, 1 February 2013 (UTC)

I think another joke is in the fact that you don't know which Unix is running on the bomb so you don't actually know which parameter layout is supported. tar --help for example may or may not be valid since -- is a GNU extension.

tar -bvzx for a tar.bzip2 .... wait... no... argh... I've always just trusted my fingers.. -- 10:14, 1 February 2013 (UTC)

Will tar -? be valid everywhere?. Arifsaha (talk) 19:32, 1 February 2013 (UTC)

tar -lvvb File not found. Sorry, you're dead. ~# 12:35, 1 February 2013 (UTC)

Googling tar commands would definitely take more than 10 seconds, especially considering that Rob did not take his computer. (A smartphone is an option, but...) Then again, why would "ten" be written in letters instead of numerals? Greyson (talk) 13:28, 1 February 2013 (UTC)

I think the current explantion is missing an important point: the tar commands are not that much difficult. What makes tar complicated is that there are many different implementations. The linux guy knows only gnu tar, but some unices have much different implementations and different commands. "tar --help" is certainly not available on an old hpux, for example. That make is difficult to type a valid tar command – even more if you don't know the implementation. 10:26, 1 February 2013 (UTC)

Will tar -? be valid everywhere?. Arifsaha (talk) 19:32, 1 February 2013 (UTC)

I'm a Windows user, so bear with me. Couldn't he type something like "man tar" to get the proper usage of the "tar" command on this particular system? It's a "man" command, so it shouldn't count as a try towards typing a "tar" command. Of course, maybe the bomb would explode if he entered anything else. 13:46, 1 February 2013 (UTC)

Yeah, all standard Unix installations should have man installed. But many mini installations don't, so these days Google is the standard backup.CityZen (talk) 14:58, 1 February 2013 (UTC)

Randall's joke is spot on, as usual. I've been using UNIX for nearly 30 years. Windows User's solution is elegant. Before Google there was the man command. In all seriousness, productivity on a UNIX box can be greatly enhanced simply by keeping good notes. I keep patterns of all sorts of UNIX commands handy so I don't have to look them up. As Wikipedia implies, tar -tf (I prefer -tvf) should be memorized because one quickly learns that one should always inspect tarballs before unpacking them. tbc (talk) 14:11, 1 February 2013 (UTC)

One of the reasons that tar is so useful is that it can often do exactly what you want when other, more obvious commands cannot. For instance, recursively copying a directory from one place to another (using "cp") can be tricky when symbolic links are involved, and thus people memorize incantations like "tar cf - . | (cd dest; tar xf -)". As well, it's a standard tool that's guaranteed to be found on every Unix installation (unlike zip/unzip).CityZen (talk) 14:58, 1 February 2013 (UTC)

tar --help. Problem solved. Davidy22[talk] 15:21, 1 February 2013 (UTC)

Maybe tar -? is better?. Arifsaha (talk) 19:32, 1 February 2013 (UTC)

What about "tar xf foo.tar"? I always assume options without dash work everywhere because options they are the original scheme. Of course, foot.tar might be absent, but in my view, the command itself remains valid. As to the time limit: I imagine a countdown starts when the first key is hit - that leaves little time for "man tar". 16:49, 1 February 2013 (UTC) madd

I think the clock is already counting down. So probably they've discovered the bomb with still some minutes on the display. They call Bob when there is a minute left, He arrives with 25 sec's on the display and 15s later the screendump is made... 22:33, 1 February 2013 (UTC)

This makes sense. --Shine (talk) 22:41, 1 February 2013 (UTC)