用户目录下面的 .bashrc 最好是先从 cp /etc/bash.bashrc .bashrc 复制一份过来，然后，下面是我从archlinux wiki找到的解决方案，应该会跟bash completion 冲突，如果你没有使用 completion,可以试试下面的办法：
Customize per-command Note: Using the complete builtin may cause conflicts with bash-completion. By default Bash only tab-completes file names following a command. You can change it to complete command names using complete -c: ~/.bashrc complete -c man which or complete command names and file names with -cf: complete -cf sudo