Question: If you are root, and you issue 

```
rm -rf / 

```

Then how far can the command go? Can you recover data from this kind of an action? Even after the binaries are gone, would the running processes still be active? What would it take to make the same physical machine boot again? What files would you need to restore to make this happen?

I could try this on a VM and see, but I want to know the rationale behind what to expect if I do this.

Answer: 
This command does nothing, at least on the OS I use (Solaris) with which this security feature was first implemented:

```
# rm -rf /
rm of / is not allowed

```

On other \*nix, especially the Linux family, if a recent enough Gnu rm is provided, you would need to add the `--no-preserve-root` option to enable the command to complete (or at least start).

How far would this command go is undefined. It depends on plenty of more or less unpredictable events. Generally, processes can run even after their binaries have been removed.
One can't simply destroy his/her system by issuing `rm -rf /` as root. Initially, the command will be issued under fail-safe mode, which will restrict the usage of `rm` on `/` but even with `--no-preserve-root` as an argument, the running system will not permit the removal of running processes from the disk; however, the rest of the programs and files will be removed, leaving an unusable system with (almost) no programs to run! Please check the screenshots tarred here, the command was issued in Arch Linux in Virtual Box: <http://bit.ly/q9CsA4>