​​https://www.jianshu.com/p/f5635f967f2a​​

vi /etc/bash.bashrc

反注释掉该部分内容即可

1.  #enable bash completion in interactive shells  
2.  #if ! shopt -oq posix; then  
3.  #      if [-f  /usr/share/bash-completion/bash_completion ]; then  
4.  #          . /usr/share/bash-completion/bash_completion  
5.  #      elif [ -f /etc/bash_completion]; then  
6.  #           . /etc/bash_completion  
7.  #      fi  
8.  #fi

懂得,原来世界如此简单!