===== WPA without NetworkManager or alike =====
<code>
$ sudo chmod 0600 /etc/network/interfaces
$ sudo wpa_passphrase myssid my_very_secret_passphrase
</code>

The output will be similar to this:
<code>
network={
        ssid="myssid"
        #psk="my_very_secret_passphrase"
        psk=ccb290fd4fe6b22935cbae31449e050edd02ad44627b16ce0151668f5f53c01b
}
</code>

Configure /etc/network/interfaces:
<code>
iface wlan0 inet dhcp
    wpa-ssid myssid
    wpa-psk ccb290fd4fe6b22935cbae31449e050edd02ad44627b16ce0151668f5f53c01b

</code>

==== References ====
  * https://wiki.debian.org/WiFi/HowToUse