raspberry pi 4 wifi setup using command line only – bash

• find the wifi adaptor name

lshw

ls /sys/class/net

it was wlan0 in my case

• edit /etc/netplan/50-cloud-init.yaml

network:
    ethernets:
        eth0:
            dhcp4: true
            optional: true
    version: 2
    wifis:
        wlan0:
            optional: true
            access-points:
                    "SSID-NAME":
                            password: "your_password"
            dhcp4: yes

• Test the config

netplan try
netplan --debug try

This command will make the above changes for 120seconds if anything wrong it will be reverted back. OR you can hit Enter to make the changes.

• apply config

netplan generate 
netplan apply

#enable wifi module

modprobe brcmfmac

#disable
modprobe -rv brcmfmac


nano /etc/modprobe.d/raspi-blacklist.conf

blacklist brcmfmac
blacklist brcmutil

• Stop wifi without reboot

#disable
rfkill block wifi


#enable
rfkill unblock wifi

• Using NMCLI

nmcli d

nmcli d wifi list

nmcli d wifi connect my_wifi password <password>

#### with BSSID
root@lp-arm-3:~# nmcli device wifi list
IN-USE  BSSID              SSID            MODE   CHAN  RATE        SIGNAL  BARS  SECURITY  
        xx:06:C3:CD:57:xx  TP-Link_123    Infra  153   270 Mbit/s  100     ▂▄▆█  WPA2      
*       xx:06:C3:CD:57:xx  TP-Link_123    Infra  2     130 Mbit/s  93      ▂▄▆█  WPA2 

====================
nmcli d wifi connect xx:06:C3:CD:57:xx password PASSWORD

More : https://raspberrypi.stackexchange.com/questions/108636/setting-wifi-up-via-the-command-line-ubuntu-server-18-04-4-lts-raspberry-pi-4

https://huobur.medium.com/how-to-setup-wifi-on-raspberry-pi-4-with-ubuntu-20-04-lts-64-bit-arm-server-ceb02303e49b

https://ubuntu.com/core/docs/networkmanager/configure-wifi-connections