1.安装wget下载工具
yum install wget -y
2.下载
wget https://rpmfind.net/linux/centos/7.9.2009/os/x86_64/Packages/bash-completion-2.1-8.el7.noarch.rpm
3.安装
rpm -ivh bash-completion-2.1-8.el7.noarch.rpm
3.配置立即生效
source /etc/profile
4.测试
输入任意命令，如systemctl re 按Tab键会给出提示
