7mo ago

Old XKCD, still relevant

Was trying to extract a totally legit copy of Skate 3 I downloaded today to play on my Steam Deck

157 comments

tar --help
- In the true spirit of UNIX, it’s tar -h
  
  F
  
  It's tar --help on my system 💥
  
  tar -?, -h is dereference or smth.
  
  Nope, tar spec doesn't say anything about a help message. The man spec OTOH requires at least syntax documentation for all standard utilities to be present on the system.
- You just killed us all by putting a space between the dashes
  
  Fuckin autocorrect was the death of us all.
  
  Or by using gnu style options on potentially bsd tar

undefined

tar -h
- Just tar, no arguments. Does nothing, still a valid command, no?
  
  Exit code 2 -> boom
- undefined
  
  tar: You must specify one of the '-Acdtrux', '--delete' or '--test-label' options Try 'tar --help' or 'tar --usage' for more information.
- Boom. tar --help for anyone wondering

I do tax -xvf filename
- tax
  Boom.
  
  ah fuck, didn't even notice
  
  I like the way you pointed that out lmao
- .... aaaaaand you've killed us all.

tar -czvf tar_name.tar.gz ./
- I even read this aloud in my head as "CREATE ZE VUCKING FILE" in a particularly bad German accent same as over 20 years ago when a friend I worked for drilled it in my head.
  
  Read it in tf2 medics voice
  
  lol that’s honestly a great mnemonic
- Yep, have this one committed to memory. Though if it asked me to uncompress a tarball, then I'd be fucked
  
  tar xzvf this_awesome_file.tgz
  … fixed. Apparently I can’t type.
- File not found, now we are dead.
  
  Sounds like an error message from a valid tar command

tar --version
You're welcome
- I'd have gone with tar --help
  
  It's insane that this isn't consistent.
  Any combination of -h, -? and --help exists between tools (from 0 to all 3 of them)
- Sorry, the bomb was running MacOS. Your command was not valid and you've doomed us all.
  
  It's literally there at the bottom.
  What isn't valid is MacOS, it's macOS now.

Somehow, idk why. This one is stuck in my head:
undefined

tar -zxvf filename.tar.gz
- tar xzvf
  eXtract Ze Vucking File
  
  I have to do this command often at work and I can never remember the letters perfectly. This is actually useful, thanks!
- The bomb runs AIX. I'm sorry, you're dead
  
  tar zxvf filename.tar.gz file?
- Same, never used a mnemonic for it or anything, just
  zxvf
  Like it's any other word
  
  z=zip (default in most tar), x=eXtract, v=verbose (not needed in most cases), f=target

undefined

tar --version
- Read my mind. :D

tar -xzf stands for tar eXtract Ze Filez
- I like tar xaf (eXtract All Files) better.
- You can skip the z; tar is smart enough to figure it out on its own

tar --help
- That was my first thought too lol
  
  Rofl me too twins

tar --version
- Or is it -v
  
  -v is verbose
  
  Depends. Short options are probably safer if the particular version and flavor of tar are unknown.

There's an easy mnemonic for that : Compress Ze Vucking File !
- Always think about tar commands in your best German accent !

How does it verify the command is valid? Does it run what I enter?
If so, just give it an infinite loop followed by some attempt at a tar command:
undefined

while true; do :; done; tar -xyz
- Next time I build a bomb I let the timer continue while the command is running.
  
  Yeah, what kind of idiot doesn't parallelize their timer function.
- Blue Team: "Okay everyone let's make sure this is absolutely the correct input"
  Red Team: "Lmao lets try this 90mb list of bash command injection patterns"
- i assume its looking for exit code of 0
  
  echo || tar -xfzhd

I'd like to know if there are any XKCDs that are no longer relevant.
- I'd like to know if there's an XKCD about an XKCD that's no longer relevant.
  
  There are some that were wrong to begin with, I remember 622 bothering me.
  https://xkcd.com/622/
  But it could also just be that in the comic, the professor is wrong.
- This one, if by unix he also means modern linux systems. Nowadays you can simply use tar xf my-file.tar.whatever and it should work on most linux systems (it worked on every modern linux system I've tried and every compressed tar file I've tried). I don't think it is hard to remember the xf part.

I hitched my horse to just what I consider the basics--zip and unzip--and that has made it easy for me. But I've been stuck on those.
Extract anything:
undefined

tar xf <archive_file>
Create a tbz2 archive:
undefined

tar cjf <archive_file.tbz2> <stuff to put in it>
(And tossing in a -v is pretty universal, if that's your thing.)
Some day, instead of commenting on a ~~reddit~~ Lemmy post, I think I'll Google how to tell it to use .xz.
Ok, you know what? Today is finally that day. It's just capital -J instead of lower-case -j! That's easy enough to remember, I guess.
- Stay by the phone always. We may need you to defuse a bomb someday.
- Never thought I'd learn how to use tar on a meme post.
  
  Memes are one of the best source for Linux info 👍.

tar -cvzf /etc/
Edit: we're dead :(

Actually this reminds me, what is the deal with tar command recommendations to use or not use dash? I know GNU tar accepts both (e.g.) tar xvf file.tar and tar -xvf file.tar, but at some points people were like "NO! Don't use the dash! It's going to maybe cause issues somewhere, who knows!" and I was like "OK". Something to do with people up designing the Unix specs?
- I didn't even know the dash was optional. I guess you learn something new everyday.
  
  I still use it though. Its how I learned it all those years ago and its ingrained as muscle memory when typing the command.
- idk if it's optional why bother typing it
  
  personally, it is a little easier to read, especially in a script. and its more consistent with other commands
- POSIX. POSIX didn't get designed but documented behaviour that was portable between different UNIX flavours and was then declared a standard.
  If you're annoyed by it just consider the xvf in tar xvf to be a subcommand as pull is in git pull. Tar simply has a fancy subcommand syntax. At least it's not dd.
- No idea, but with tar I never use dashes. Just tar xf away.

tar -xvf or we all kill
- shouldnt there be a filename argument ?
  
  Yes. However, if you had skipped the -f, it would have been valid. Without the filename argument, it assumes it should extract from the tape drive (TAR = Tape ARchive). The tape device is probably something like /dev/rmt0, but you don't need to specify that. Using the -f is technically an exception which means "instead of extracting from the tape like you'd normally do, pretend that this file is the tape device instead."
  
  I definitely still killed us all, but at the same time how are you supposed to know any of the filenames if none are given from the comic? I guess my real answer is to 'tar -xvf' then hit tab with hopes of decent file completion functionality lol
- ya blew it kid

I just can recall tar xvzf but can't even remember what it's supposed to do.
- eXtract, Verbose, gZip, File.
  Not sure why it doesn’t need the dash though.
  
  The dash used to be how to could tell how long someone had been using tar. If they started with Linux, they probably use a dash. If they started on a UNIX variant, they probably don’t. Either way, the dash isn’t needed.
  Also recently learned that recent versions of tar will autodetect compression. So for extraction, you just need “tar xf “
  
  I always learnt it as Xtract Zee File and to make a tar ball, you want to Compress Zee File
  
  tar doesn’t need dashes because it’s weird.

Remember: Just tell tar to Xtract Z File.
- Xtract gZipped File

I guess man tar is cheating, but it is a command involving tar. Not a command using tar, but a tar command...
- I suppose tar --help would technically be a valid invoking of the binary itself if man tar doesn't
  
  But it would not work on older non-GNU versions of tar.
  GNU introduced the "--foo" style long options, and it was a long time before Unix versions began adopting them.
- It didn’t say you could only enter one try, just that you had 10 seconds. The man page should give you something
  
  True. But then I would use curl cheat.sh/tar

Sudo halt -fn

tar -xzvf file.tar
- That's what I had in mind too. Tar's arguments are really intuitive.
  x - eXtract
  z - use gZip
  v - Verbose
  f - File (requires the path as an argument)

I know tar zxf and xjf off by heart. I probably do 100x as many extracts as creates. Tar is a stupidly antiquated command though.
- Why remember/include the algorithm? Tar can infer that. It's just bsdtar xf filename.* for everything. (bsdtar handles .zip as well)
  
  The bomb said tar.

tar cJf file.tar.xz /path/to/file
tar xJf file.tar.xz /path/to/file.tar.xz -C /path/to/untar
is not very hard to remember
- Unless you use it daily, I think that's something I'd struggle with memorising, I'd just alias it tbh along with ls options

tar --help

tar x
- tar --help

| man tar
- This is a valid man command, but not a tar command
  
  I’ll use the man page to find a command; it said 10 seconds, not 1 try!

Do people not use tab complete?
- Found the person who's never used tar :-P
  
  Thats not true and
  I am fully aware that there are 127 flags. That just makes this even sillier because you have so many valid options to disarm the bomb.

tar -zxvf yourmom.tgz /home/xkcd/yourmomnude/* This was wrong. I intended to be creating a file -zcvf.

tar -cf file.tar directory/
- that was 8 seconds. close one, i saved us all
  
  How do you know directory exists? 😨

tar, the tape archiver, I used it with tape, early 90s

I just use ouch

I've never had a problem remembering tar, but properly using PV, somehow I'm just not able to store that information in my brain.

I memorized tar -cavf file.tar.bz2 directory/* and tar -xavf file.tar.bz2

The fact that this thread contains, like, TONS of invalid invocations that people have been editing for correctness is fucking hilarious.
Also, QED 🤠

cpio is way worse

tar --extract --file file.tar.gz

I always remember that it's eXtract Ze File, tar -xzf... But I'll be honest, I've not used it in years and years

Anyone else make an untar.sh?

All those years of using nautilus have made me weak

undefined

touch foo; tar cvf foo.tar foo
My fucking autocorrect decided that cvf should have been xvf. I caught it before I hit enter to close out the code block, but wtf? When did my keyboard develop opinions on command args‽

Now do a standard pax command.

Tar -xvf

Well, bye everyone.

157 comments