Is it possible to remove the root directory?

6

1

I noticed in the documentation for rm as obtained by rm --help the following flag:

--no-preserve-root  do not treat `/' specially

What does this mean? Is it actually possible to delete the root directory, apart from its contents? What consequences would that have?

gerrit

Posted 2013-01-28T16:59:43.243

Reputation: 1 357

2Yes, they put in place a protection from people who try rm -rf /. They put that in place because yes, you can and you're system will be useless. – nerdwaller – 2013-01-28T17:02:10.333

In my understanding, rm -rf / deletes the contents of the root directory; but wouldn't the root directory itself still exist? – gerrit – 2013-01-28T17:03:18.383

1@gerrit: Yes, it would. But this command is precisely why the "preserve root" mode was added: rm refuses to operate recursively on / unless you add the --no-preserve-root option. – user1686 – 2013-01-28T17:04:14.397

Answers

16

You cannot delete the root directory itself. However, you can use rm's recursive mode to delete everything in that directory – the infamous rm -rf / command.

The "preserve root" mode stops rm from recursively operating on the root directory:

$ sudo rm -rf /
rm: it is dangerous to operate recursively on ‘/’
rm: use --no-preserve-root to override this failsafe

The --preserve-root option was added to GNU rm in 2003 (commit 9be74f6f125b2be), and was made the default behavior in 2006 (commit aff5a4f2ab86f).

Some say it is because pranksters in #ubuntu kept telling newbies to run rm -rf / – and many did. Some say it is because it is too easy to mistype rm -rf / tmp/junk. Some say it is to prevent accidents when running rm -rf $dir/ when $dir is empty. All we know is, he's called th

Either way, it is part of POSIX requirements nowadays. Solaris rm also has similar protection, as does OpenBSD.

user1686

Posted 2013-01-28T16:59:43.243

Reputation: 283 655

3Did you actually dare to type that for real? – gerrit – 2013-01-28T17:05:51.717

2Linux is cheap, as are old computers. Admit that you've done it on a decommissioned system to see how to quickly create disk space. And the answer is yes. – Fiasco Labs – 2013-01-28T17:19:30.230