通过已build立的ssh连接进行文件复制

1. 如果我已经build立了一个从系统源到系统目的地的ssh连接，我可以在一个ssh连接中将一个文件从系统源复制到系统目的地

是的， man ssh_config并查看ControlMaster和ControlPath ：

  ControlMaster Enables the sharing of multiple sessions over a single network connection. When set to “yes”, ssh(1) will listen for connections on a control socket specified using the ControlPath argument. Additional sessions can connect to this socket using the same ControlPath with ControlMaster set to “no” (the default). These sessions will try to reuse the master instance's network connection rather than initiating new ones, but will fall back to connecting normally if the control socket does not exist, or is not listening. Setting this to “ask” will cause ssh to listen for control connections, but require confirmation using the SSH_ASKPASS program before they are accepted (see ssh-add(1) for details). If the ControlPath cannot be opened, ssh will continue without connecting to a master instance. X11 and ssh-agent(1) forwarding is supported over these multiplexed connections, however the display and agent forwarded will be the one belonging to the master connection ie it is not possible to forward multiple displays or agents. Two additional options allow for opportunistic multiplexing: try to use a master connection but fall back to cre‐ ating a new one if one does not already exist. These options are: “auto” and “autoask”. The latter requires confirmation like the “ask” option. ControlPath Specify the path to the control socket used for connection sharing as described in the ControlMaster section above or the string “none” to disable connection sharing. In the path, '%L' will be substituted by the first component of the local host name, '%l' will be substituted by the local host name (including any domain name), '%h' will be substituted by the target host name, '%n' will be substituted by the original target host name spec‐ ified on the command line, '%p' the port, '%r' by the remote login username, and '%u' by the username of the user running ssh(1). It is recommended that any ControlPath used for opportunistic connection sharing include at least %h, %p, and %r. This ensures that shared connections are uniquely identified. 

将这2行添加到~/.ssh/config ：

 ControlMaster auto ControlPath ~/.ssh/control:%h:%p:%r 

然后退出任何现有的SSH连接，并build立到服务器的新连接。 现在在第二个窗口中， scp会话将在第一个窗口中传输。

另外，因为我通过SSH连接到系统目的地，有没有办法列出系统源文件？

远程端口转发是你在找什么。

man ssh ：

  -R [bind_address:]port:host:hostport Specifies that the given port on the remote (server) host is to be forwarded to the given host and port on the local side. This works by allocating a socket to listen to port on the remote side, and whenever a connection is made to this port, the connection is forwarded over the secure channel, and a connection is made to host port hostport from the local machine. Port forwardings can also be specified in the configuration file. Privileged ports can be forwarded only when logging in as root on the remote machine. IPv6 addresses can be specified by enclosing the address in square braces. By default, the listening socket on the server will be bound to the loopback interface only. This may be over‐ ridden by specifying a bind_address. An empty bind_address, or the address '*', indicates that the remote socket should listen on all interfaces. Specifying a remote bind_address will only succeed if the server's GatewayPorts option is enabled (see sshd_config(5)). If the port argument is '0', the listen port will be dynamically allocated on the server and reported to the client at run time. When used together with -O forward the allocated port will be printed to the standard out‐ put. 

在服务器上，通过键入以下命令从ssh命令行创build远程端口转发：

• ~C input
• -R 2302:localhost:22 input

你会看到这样的东西：

 [user@server ~] $ ssh> -R 2302:localhost:22 Forwarding port. 

那么您可以通过运行下列命令列出客户端上的文件：

 ssh localhost -p 2302 "ls" 

man ssh_config显示：

ControlMaster启用通过单个networking连接共享多个会话。 当设置为“yes”时，ssh（1）将侦听使用ControlPath参数指定的控制套接字上的连接。 其他会话可以使用ControlMaster设置为“no”（缺省值）的相同ControlPath连接到此套接字。 这些会话将尝试重新使用主实例的networking连接而不是启动新的连接，但是如果控制套接字不存在或不在监听，则会回退到正常连接状态。