LINUX下 如何验证系统用户名和密码是否正确。

#!/root/download/expect-5.30/expect -f
#usage:shell_test name password

if {$argc!=2}/
{
send_user "Usage:shell_test name password"
exit 1
}
set name [lindex $argv 0]
set password [lindex $argv 1]
set isSend 0
spawn ssh -t "${name}@localhost"
expect /
{
"* (yes/no)*" {send "yes/r"} /
"* password:*" /
{
send "${password}/r"
set isSend 1
} /
default {send_user "error"}
}
if {$isSend==0}/
{
expect "* password:*" {send "${password}/r"} /
default {send_user "error"}
}
expect /
{
"Permission denied" {send_user "Not allowed"} /
"*~]" /
{
send_user "OK"
send "exit/r"
} /
default /
{
send_user "error"
exit 1
}
}
exit 0