解决shell脚本中 telnet ap自动输入用户名和密码以及回车符

#!/bin/bash
function change_ap {
  (
  s=`stty -g`;
  str=$"\n"
  sstr=$(echo -e $str)
  stty raw -echo;
  sleep 2;
  echo "xxxx";
  sleep 2;
  echo "xxxxx";
  sleep 2;
  echo "system-view";
  sleep 2;
  echo "wlan service-template 3 crypto";
  sleep 2;
  echo "service-template disable";
  sleep 2;
  echo "ssid 8888888";
  sleep 2;
  echo "service-template enable";
  sleep 2;
  echo "save";
  sleep 2;
  echo "Y";
  sleep 2;
  echo  "$sstr";
  sleep 2;
  echo "Y";
  dd bs=1 cbs=1;
  stty $s
  ) | telnet 172.16.1.251 | cat
}
change_ap