Configure Wireless Networking in Ubuntu via the Command Line

First, you need to install the relevant software. You need to have a wired connection at this point, otherwise this wont work.

sudo apt-get install wireless-tools wpasupplicant

If you are connecting to an open network, you wont need wpasupplicant. Next, you need to “bring up” (essentially this means activate) your WiFi interface. So, issue:

sudo ifconfig wlan0 up

Next, to make sure your wireless device is working as it should issue:

iwconfig
and then
sudo iwlist scanwpa_passphrase YOURSSID YOURWIFIPASSWORD

This will result in something that looks like this:

network={
ssid="YOURSSID"
#psk="YOURWIFIPASSWORD"
psk=fe727aa8b64ac9b3f54c72432da14faed933ea511ecab1 5bbc6c52e7522f709a
}sudo nano /etc/network/interfaces

sudo vi /etc/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant                        ctrl_interface_group=0

eapol_version=2
ap_scan=1
fast_reauth=1
country=NL

### Associate with any open access point
###  Scans/ESSID changes can be done with wpa_cli
network={
  ssid=""
  key_mgmt=NONE
  priority=1
}

# WEP
network={
  ssid="ubuntuwifi"
  scan_ssid=1
  key_mgmt=NONE
  wep_key0="OpenSesame"
  wep_key1="OpenOtherSesame"
  # Use the correct key..
  wep_tx_keyidx=0
  priority=5
}

# WPA/WPA2
network={
  ssid="ubuntuwifi"
  scan_ssid=1
  psk=24f87a7583001eb7cea2394bbdb04eb2d3641f0b907dd31bd286be628c1841f8
  priority=5
  ## The configuration items listed below do not need to be set, the defaults are
  ## pretty 'let us do it for you'.
  ## See /usr/share/doc/wpasupplicant/wpa_supplicant.conf.gz for more information.
  # key_mgmt=WPA-PSK
  # proto=WPA RSN
  # pairwise=CCMP TKIP
  # group=CCMP TKIP
}

start    WPA/WPA2

/sbin/wpa_supplicant -c /etc/wpa_supplicant.conf -i wlan0 -D  -B -f /var/log/wpa_supplicant.log