“ssh-keygen -F”似乎为给定的主机名返回一个主机密钥（第一个匹配？），而“ssh-keyscan”似乎返回所有匹配的，但顺序不清楚。
两者的具体区别是什么？
从ssh-keygen(1)页：
-H Hash a known_hosts file. This replaces all hostnames and addresses with hashed representations within the specified file; the original content is moved to a file with a .old suffix. These hashes may be used normally by ssh and sshd, but they do not reveal identifying information should the file's contents be disclosed. This option will not modify existing hashed hostnames and is therefore safe to use on files that mix hashed and non-hashed names.
并从ssh-keyscan(1)页：
-H Hash all hostnames and addresses in the output. Hashed names may be used normally by ssh and sshd, but they do not reveal identifying information should the file's contents be disclosed.
前一个朗姆酒本地 ，哈希你的~/.ssh/known_hosts文件，而后者联系远程服务器来请求其密钥。