How to check status of Wi-Fi adapter through command line?
You can use the ifconfig command, e.g.:

$ ifconfig en0 
en0: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
    ether # Removed for Security. 
    inet6 fe80::c44:6ce5:5d57:5b93%en0 prefixlen 64 secured scopeid 0x9 
    inet 192.168.2.101 netmask 0xffffff00 broadcast 192.168.2.255
    nd6 options=201&lt;PERFORMNUD,DAD&gt;
    media: autoselect
    status: active
$


You can also filter the output, e.g.:

$ ifconfig en0 | awk '/status:/{print $2}'
active
$ 


When not active the output is, e.g:

$ ifconfig en0 | awk '/status:/{print $2}'
inactive
$




If you do not know the device name for the Wi-Fi network adapter, you can use the following examples:

$ networksetup -getairportpower $(system_profiler SPAirPortDataType | awk -F: '/Interfaces:/{getline; print $1;}')
Wi-Fi Power (en0): On
$


Or:

$ ifconfig $(system_profiler SPAirPortDataType | awk -F: '/Interfaces:/{getline; print $1;}') | awk '/status:/{print $2}'
active
$