Iwlist

iwlist shows you available wireless networks. It is a command that is part of the Wireless Tools. To install it, install the Wireless Tools.

Example usage: santosh:~ # iwlist eth3 scanning eth3     Scan completed : Cell 01 - Address: 00:0F:C9:01:F5:F4 ESSID:"SWWLAN" Protocol:IEEE 802.11bg Mode:Master Channel:10 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality=59/100 Signal level=-72 dBm  Noise level=-72 dBm Extra: Last beacon: 24ms ago santosh:~ #

In this case, eth3 is the wireless network device. To find out which is your wireless network device, you can use iwconfig.