fix(修改 github hosts 错误):

1. 增加备份hosts
2. 从替换编程追加

Author: gclm

centos.sh

@@ -23,7 +23,8 @@ dnf install -y curl wget vim
 
 # 增加github hosts
 echo "==> 增加github hosts"
-cat>/etc/hosts<<EOF
+cp /etc/hosts /etc/hosts.bak
+cat>>/etc/hosts<<EOF
 # 代理
 151.101.0.133 raw.githubusercontent.com
 199.232.68.133 raw.githubusercontent.com