Connect to WPA network (dhcp)

First of all, we need a configuration file (example.conf), and of course you need to know the details of the network:

network = {
    ssid="NAME_OF_THE_NETWORK"
    proto=WPA
    key_mgmt=WPA-PSK
    pairwise=TKIP
    group=TKIP
    psk="NETWORK_PASSWORD"
    wpa_ptk_rekey=600
}

Then, as root or using sudo you need to execute the following lines.
Please note that in this case my wireless interface is wlan0.

pylon~ $  wpa_supplicant -B -D wext -i wlan0 -c example.conf
pylon~ $  dhcpcd wlan0