Linux: ssh是什么协议？

安全外壳协议（SSH）是一种在不安全网络上提供安全远程登录及其它安全网络服务的协议。Secure Shell，又可记为S S H

NAME
ssh - OpenSSH SSH client (remote login program)

SYNOPSIS
ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec] [-D
[bind_address:]port] [-e escape_char] [-F configfile]
[-i identity_file] [-L [bind_address:]port:host:hostport]
[-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port] [-R
[bind_address:]port:host:hostport] [-S ctl_path]
[-w local_tun[:remote_tun]] [user@]hostname [command]

DESCRIPTION
ssh (SSH client) is a program for logging into a remote machine and for
executing commands on a remote machine. It is intended to replace rlogin
and rsh, and provide secure encrypted communications between two
untrusted hosts over an insecure network. X11 connections and arbitrary
TCP ports can also be forwarded over the secure cha