Autocompletion doesn't work while logged as root

In Debian:

Check your /root/.bashrc file for these lines

if [ -f /etc/bash_completion ]; then
  . /etc/bash_completion
fi

If they do not exist add them to the end of the file using your favorite text editor.

In CentOS:

# yum install bash-completion

How do I use bash Autocomplete feature?