Expect自动ssh登录

#!/usr/bin/expect 
set timeout 5
set cmd_prompt "]#|~]?"
set server [lindex $argv 0] 
set user [lindex $argv 1] 
set passwd [lindex $argv 2] 

spawn ssh -l $user $server 
expect { 
"(yes/no)" { send "yes\r"; exp_continue } 
"password:" { send "$passwd\r" } 
}
#expect "$cmd_prompt" interact
expect "*Last login*" interact