/*****in/iwconfig 的是:
lo no wireless extensions.
eth0 no wireless extensions.
eth1 unassociated ESSID:off/any
Mode:Managed Frequency=nan kHz Access Point: Not-Associated
Bit Rate:0 kb/s Tx-Power:16 dBm
Retry limit:15 RTS thr:off Fragment thr:off
Power Management:off
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:320 Missed beacon:0