Linux平台启用systemctl自动补全

1. 安装 bash-completion

Debian/Ubuntu

apt update && sudo apt install bash-completion

RHEL/CentOS

yum install bash-completion

2. 手动加载补全脚本

立即生效，重新登录SSH测试，重启后无需再次执行
source /usr/share/bash-completion/bash_completion