ubuntu实现自动补齐的方法：
1.以root权限利用vi编辑器打开/etc/bash.bashrc文件，命令：
sudo vi /etc/bash.bashrc
2.找到/etc/bash.bashrc文件中的下列代码进行修改。
#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
需要去掉去掉 if 到 fi 之间的注释 ＃ 号，例如：
#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.最后刷新保存一下即可，命令：
source /etc/bash.bashrc
