1) iwconfig
Iwconfig command is used to configure wireless interface in Linux. It is similar to ifconfig command but with lots of wireless paramters.
Sample Commands
iwconfig eth0 essid My Network
iwconfig eth0 channel 3
iwconfig eth0 mode Managed
iwconfig eth0 rts 250
iwconfig eth0 key 0123-4567-89
iwconfig eth0 txpower 15
2) Atheros driver commands ( Madwifi)
a) iwconfig
b) wlanconfig
c) iwpriv
iwconfig ath0 essid test123
ifconfig ath0 up
wlanconfig ath0 create wlandev wifi1 wlanmode ap
iwconfig ath0 essid test123
iwpriv ath0 mode 11G
iwconfig ath0 channel 1
ifconfig ath0 up
wlanconfig ath0 list chan
iwconfig ath0 channel 36
iwpriv wifi0 getCountry
iwpriv wifi0 getCountryiD
iwpriv wifi0 setCountry US
iwpriv ath0 mode 11NAHT20
wlanconfig ath0 destroy