linux expect 中传入退出码来判断进程的执行情况

expect是linux里面用于交互式输入命令的
但expect中间可能要做比较多的判断，判断返回值是否成功或者失败来确定是否继续朝下执行。给一个简单的case.

/usr/bin/expect <<EOF
spawn ssh root@ip
expect {
			"expect success message" {
			       send "echo success\n";
			       exit 0;
			       exp_continue;
			}
			"expect error message" {
			       send "echo failed \n";
			       exit 1;
			       exp_continue;
			}
}
EOF
if [ "$?" -ne 0 ]; then
	echo "failed"
	exit 1;
else
	echo "success"
	exit 0;
fi