Check wifi's working

1lspci -k

Or for usb wifi:

1dmesg | grep usbcore

... and hopefully it'll say the new interface is registered.

Check if a wifi interface has been created

1ip link

or

1iw dev

Assuming it's wlan0, bring it up with

1ip link set wlan0 up

Error messages probably means your wireless chipset requires a firmware to function. In this case, check the kernel messages for firmware being loaded

1dmesg | grep firmware

Utilities

iw doesn't do wpa/wpa2. wpa_supplicant does everything. iwd does everything except WEXT encryption.

Connecting

Get the link status:

1iw dev wlan0 link

Scan for available points:

1iw dev wlan0 scan

The connecting commands do not cover wpa2.