expect ssh首次登录自动判断(yes/no)?

v-lhb-prx01:/root/sbin# sh ./expect.sh
spawn ssh root@192.168.32.16
The authenticity of host '192.168.32.16 (192.168.32.16)' can't be established.
RSA key fingerprint is da:3a:61:09:e4:f6:46:d7:01:08:1a:6c:b9:41:e8:4c.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.32.16' (RSA) to the list of known hosts.
root@192.168.32.16's password:
Last login: Wed May 27 09:37:32 2015 from 192.168.33.107

v-dev-redis02:/root# df -h
Filesystem                Size  Used Avail Use% Mounted on
/dev/mapper/vg00-lv_root  7.7G  5.6G  1.8G  77% /
tmpfs                     499M     0  499M   0% /dev/shm
/dev/sda1                 194M   29M  155M  16% /boot
v-dev-redis02:/root# exit
logout
Connection to 192.168.32.16 closed.

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expect {
"(yes/no)?" {
send "yes\n"
expect "password:"
send "$passwd\n"
}
"password:" {
send "$passwd\n"
}
}
# 下面测试是否登录到
expect "#"
send "df -h\n"
send "exit\r"
expect eof