Warn people when they execute harmfull shell commands

[Christoph Langner]

Binary package hint: bash

When a user does something really stupid like

$ sudo apt-get remove libc6

he'll get a very urgent warning, telling him that this is a bad idea:

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  acpi acpi-support acpid adduser alacarte alsa-base alsa-utils anacron apmd
  apparmor apparmor-utils apport apport-gtk
...
  util-linux) tzdata (due to util-linux) libslang2 (due to util-linux) zlib1g
  (due to util-linux)
0 upgraded, 0 newly installed, 1354 to remove and 0 not upgraded.
Need to get 0B of archives.
After unpacking 3136MB disk space will be freed.
You are about to do something potentially harmful.
To continue type in the phrase 'Yes, do as I say!'
 ?]

Sometime people do something like this out of bad luck or bad typing

$ sudo rm -rf / path/to/foo/bar

Which will delete the complete system including their data. I think that people should get a warning, wenn they try something which will have a really bad result for their system, like

$ sudo rm -rf /
$ sudo chmod -R 777 /
$ sudo chown -R foo.bar /

similar to the warning of apt-get.