$ sudo iwconfig
[sudo] password for sjbrown: 
lo        no wireless extensions.

wlan0     IEEE 802.11abgn  ESSID:""  Nickname:""
          Mode:Managed  Frequency:2.412 GHz  Access Point: Not-Associated   
          Bit Rate:14 Mb/s   Tx-Power:32 dBm   
          Retry min limit:7   RTS thr:off   Fragment thr:off
          Power Managementmode:All packets received
          Link Quality=5/5  Signal level=0 dBm  Noise level=-91 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

eth0      no wireless extensions.