1、从服务器下载文件到本地
scp username@servername:/server_path/filename /user/local_path
2、上传本地文件到服务器
scp /path/local_filename username@servername:/server_path
3、从服务器下载文件夹（整个目录）到本地
scp -r username@servername:server_dir/ /local_path
4、上传文件夹（整个目录）到服务器
scp -r /local_path/local_dir user_name@servername:/server_path
