1、利用vi编辑器打开 /etc/bash.bashrc文件（需要root权限）
sudo vi /etc/bash.bashrc
接下来会提示输入密码
此时vi可能会出现上下左右出现问题,解决办法：
(1)执行命令 sudo apt-get remove vim-common
(2)执行命令 sudo apt-get install vim
2、找到文件中的下列代码
#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
将注释符号#去掉，即改成
#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
3、最后 source一下 /etc/bash.bashrc即可， 即
sudo source /etc/bash.bashrc
