This is based upon this [hoax question](https://serverfault.com/questions/769357/recovering-from-a-rm-rf) here. The problem described is having a bash script which contains something to the effect of:

```
rm -rf {pattern1}/{pattern2}

```

...which if both patterns include one or more empty elements will expand to at least one instance of `rm -rf /`, assuming that the original command was transcribed correctly and the OP was doing [brace expansion rather than parameter expansion](http://ss64.com/bash/syntax-expand.html).

In the OP's [explanation of the hoax](http://www.snopes.com/man-deletes-company-code/), he states:

> 
> The command [...] is harmless but it seems
>  that almost no one has noticed.
> 
> 
> The Ansible tool prevents these errors, [...] but [...] no one seemed to
>  know that, otherwise they would know that what I have described could
>  not happen.
> 
> 
> 

So assuming you have a shell script that emits an `rm -rf /` command through either brace expansion or parameter expansion, is it true that using [Ansible](https://www.ansible.com/) will prevent that command from being executed, and if so, how does it do this? 

Is executing `rm -rf /` with root privileges really "harmless" so long as you're using Ansible to do it?