How to prevent a mistaken rm -rf for specific folders

administrationrm

I think pretty much people here mistakenly 'rm -rf'ed the wrong directory, and hopefully it did not cause a huge damage.. Is there any way to prevent users from doing a similar unix horror story?? Someone mentioned (in the comments section of the previous link) that

… I am pretty sure now every unix course or company using unix sets
rm -fr to disable accounts of people trying to run it or stop them
from running it …

Is there any implementation of that in any current Unix or Linux distro? And what is the common practice to prevent that error even from a sysadmin (with root access)?

It seems that there was some protection for the root directory (/) in Solaris (since 2005) and GNU (since 2006). Is there anyway to implement the same protection way to some other folders as well??

To give it more clarity, I was not asking about general advice about rm usage (and I've updated the title to indicate that more), I want something more like the root folder protection: in order to rm -rf / you have to pass a specific parameter: rm -rf --no-preserve-root /.. Is there similar implementations for customized set of directories? Or can I specify files in addition to / to be protected by the preserve-root option?

Best Answer

To avoid a mistaken rm -rf, do not type rm -rf.

If you need to delete a directory tree, I recommend the following workflow:

  • If necessary, change to the parent of the directory you want to delete.
  • mv directory-to-delete DELETE
  • Explore DELETE and check that it is indeed what you wanted to delete
  • rm -rf DELETE

Never call rm -rf with an argument other than DELETE. Doing the deletion in several stages gives you an opportunity to verify that you aren't deleting the wrong thing, either because of a typo (as in rm -rf /foo /bar instead of rm -rf /foo/bar) or because of a braino (oops, no, I meant to delete foo.old and keep foo.new).

If your problem is that you can't trust others not to type rm -rf, consider removing their admin privileges. There's a lot more that can go wrong than rm.

Always make backups.

Periodically verify that your backups are working and up-to-date.

Keep everything that can't be easily downloaded from somewhere under version control.

With a basic unix system, if you really want to make some directories undeletable by rm, replace (or better shadow) rm by a custom script that rejects certain arguments. Or by hg rm.

Some unix variants offer more possibilities.

  • On OSX, you can set an access control list on a directory preventing deletion of the files and subdirectories inside it, without preventing the creation of new entries or modification of existing entries: chmod +a 'group:everyone deny delete_child' somedir (this doesn't prevent the deletion of files in subdirectories: if you want that, set the ACL on the subdirectory as well).
  • On Linux, you can set rules in SELinux, AppArmor or other security frameworks that forbid rm to modify certain directories.
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