安装bash-completion

brew install bash-completion

复制kubectl completion bash到completion目录

kubectl completion bash > $(brew --prefix)/etc/bash_completion.d/kubectl

查看要添加到.bash_prfile的语句：

brew info bash-completion
Add the following line to your ~/.bash_profile:
  [[ -r "/usr/local/etc/profile.d/bash_completion.sh" ]] && . "/usr/local/etc/profile.d/bash_completion.sh"

Bash completion has been installed to:
  /usr/local/etc/bash_completion.d

将以下内容添加到~/.bash_profile

vim ~/.bash_profile
追加
[[ -r "/usr/local/etc/profile.d/bash_completion.sh" ]] && . "/usr/local/etc/profile.d/bash_completion.sh"

生效

source ~/.bash_profile