From charlesreid1

Connecting to Wifi in Linux

One Time

Assuming your wireless device is wlan0,

$ wpa_supplicant -D nl80211,wext -i wlan0 -c <(wpa_passphrase "MyRouter" "MyPassword")

Permanetly

Or, one time. Either one.

First, edit /etc/network/interfaces

Add the wireless interface and WPA information:

auto wlan0
iface wlan0 inet dhcp 
                wpa-ssid MyRouter
                wpa-psk  MyPassword

Now close the file and execute the command:

$ dhclient wlan0