OpenWrt

OpenWrt is described as a Linux distribution for embedded devices.

#show connected stations
#from https://serverfault.com/questions/226046/how-to-get-a-list-of-the-connected-wifi-clients-in-openwrt-10-03
# Universal (Tested with OpenWRT 14.07 and 15.05.X)
iwinfo wlan0/wl0/ath0 assoclist

# Proprietary Broadcom (wl)
wl -i wl0 assoclist

# Proprietary Atheros (madwifi)
wlanconfig ath0 list sta

# MAC80211
iw dev wlan0 station dump

# iwinfo wlan0 assoclist

#the ubus way
ubus call wireless.accesspoint.station get

#scan for other access points
#from https://openwrt.org/docs/guide-user/network/wifi/connect_client_wifi
iw dev
iw dev wlan0 scan

iw dev wl0 scan | grep -e SSID -e signal