Show wifi password.

def wp(ssid):
    """Show wifi password."""
    if not ssid:
        ok, err = _detect_wifi_ssid()
        if not ok:
            click.secho(click.style(err, fg='red'))
            sys.exit(1)
        ssid = err
    ok, err = _hack_wifi_password(ssid)
    if not ok:
        click.secho(click.style(err, fg='red'))
        sys.exit(1)
    click.secho(click.style('{ssid}:{password}'.format(ssid=ssid, password=err), fg='green'))