this post was submitted on 09 Sep 2024
273 points (80.8% liked)

linuxmemes

20741 readers
833 users here now

I use Arch btw


Sister communities:

Community rules

  1. Follow the site-wide rules and code of conduct
  2. Be civil
  3. Post Linux-related content
  4. No recent reposts

Please report posts and comments that break these rules!

founded 1 year ago
MODERATORS
 
you are viewing a single comment's thread
view the rest of the comments
[–] crimsoncobalt@lemmy.world 17 points 1 week ago (5 children)

Does this really work? Wouldn't rm remove itself in /bin early in the process?

[–] rbn@sopuli.xyz 48 points 1 week ago* (last edited 1 week ago) (2 children)

I think it would continue even after it's own deletion as the binary is already loaded into memory, so process is not dependent on the file system. Still doubt that it'll complete successfully. Most likely the system crashes in the middle.

[–] kirk781@discuss.tchncs.de 13 points 1 week ago (1 children)

I thought - - no-preserve root also needed to be added as an argument for self destruct to completely work.

[–] elvith 11 points 1 week ago* (last edited 1 week ago) (1 children)

Yes, though you could also do rm -rf /* afaik to not need --no-preserve-root

Edit: I just realized that the * is already in the meme. So this should already work as is. Alternatively you could always use the good old way of "act now and remove all French roots of your system: rm -fr / --no-preserve-root"

[–] blibla@slrpnk.net 1 points 1 week ago (1 children)

i dont get why you can't just do sudo rm -fr /

[–] elvith 2 points 1 week ago

because it won't let you do that:

elvith@testvm:~$ sudo rm -fr /

rm: it is dangerous to operate recursively on '/'

rm: use --no-preserve-root to override this failsafe

[–] SpaceCadet@feddit.nl 1 points 1 week ago

as the binary is already loaded into memory

That’s not the reason why it continues. It’s because there’s still a file descriptor open to rm.

[–] SpaceCadet@feddit.nl 18 points 1 week ago* (last edited 1 week ago)

In Unix/Linux, a removed file only disappears when the last file descriptor to it is gone. As long as the file /usr/bin/rm is still opened by a process (and it is, because it is running) it will not actually be deleted from disk from the perspective of that process.

This also why removing a log file that's actively being written to doesn't clear up filesystem space, and why it's more effective to truncate it instead. ( e.g. Run > /var/log/myhugeactivelogfile.log instead of rm /var/log/myhugeactivelogfile.log), or why Linux can upgrade a package that's currently running and the running process will just keep chugging along as the old version, until restarted.

Sometimes you can even use this to recover an accidentally deleted file, if it's still held open in a process. You can go to /proc/$PID/fd, where $PID is the process ID of the process holding the file open, and find all the file descriptors it has in use, and then copy the lost content from there.

[–] Arcity@feddit.nl 10 points 1 week ago (1 children)

rm doesn't remove memory in RAM

[–] SpaceCadet@feddit.nl 1 points 1 week ago* (last edited 1 week ago)

That’s not the reason why it continues. It’s because there’s still a file descriptor open to rm.

[–] Johanno 9 points 1 week ago (1 children)

Since you forgot to add - - preserve-root It won't go too far. But at some point the system wants to load a file that is deleted and the kernel will panic. System crash. Delete incomplete. But rest assured, the important stuff is gone.

[–] SpaceCadet@feddit.nl 5 points 1 week ago (1 children)

Since you forgot to add - - preserve-root It won’t go too far

Go on then ... try it.

Or don't because you will erase your system. (Hint: it's in the asterisk)

[–] Johanno 2 points 1 week ago (2 children)

Or was it non preserve. I never tried it though. I guess a vm should be fine to test it. On the other hand I don't care enough.

[–] SpaceCadet@feddit.nl 2 points 1 week ago* (last edited 1 week ago)

The flag is called --no-preserve-root, but the flag wouldn't do anything here because you're not deleting root (/), you're deleting all non-hidden files and directories under root (/*), and rm will just let you do it.

Pretty sure it's --no-preserve-root or something similar.