at present, I am implementing such a shell, that can successfully log in without secret, but cannot cd to / data/bak/log, for advice
-sharp!/usr/bin/expect
set timeout 30
spawn ssh -p [lindex $argv 0] [lindex $argv 1]@[lindex $argv 2]
expect {
"(yes/no)?"
{send "yes\n";exp_continue}
"password:"
{send "[lindex $argv 3]\n"}
send "cd /data/bak/log\r"
}
interact