# apt-get install bash-completion

vi /etc/bash.bashrc

# enable bash completion in interactive shells
if ! shopt -oq posix; then
if [ -f /usr/share/bash-completion/bash_completion ]; then
. /usr/share/bash-completion/bash_completion
elif [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
fi

Yukarıdaki kod satırının ilk if den itibaren commentlerini kaldırabilirsiniz.