[linux] shell 에서 wifi 연결하기

1. connmanctrl
    $> connmanctrl
    connmanctrl> agent on
    connmanctrl> scan wifi
    Scan completed for wifi
    connmanctrl> services
        aaa     wifi_xxxxx_managed_psk
        bbb     wifi_xxxxx_managed_psk
     connmanctrl> connect wifi_xxxx_managed_psk
     ...........
     Passphrase?  pwd 입력
   
99. Troubleshooting
     Error /net/connman/service/wifi_xxxx_managed_psk: Not registered
    >> commanctrl 에서 agent on 을 호출하지 않는 경우 발생