Debian Wifi

sudo apt-get install isc-dhcp-client

sudo apt-get install firmware-atheros
sudo apt-get install firmware-brcm80211
sudo apt-get install firmware-iwlwifi
sudo apt-get install firmware-ralink
sudo apt-get install firmware-realtek

# The iw package contains the iw command.
# The wireless-tools package contains the iwconfig and iwlist commands.
# The wpasupplicant package contains the wpa_cli command.
sudo apt-get install iw
sudo apt-get install rfkill
sudo apt-get install wireless-tools
sudo apt-get install wpasupplicant

sudo rfkill list

sudo systemctl --type=service           #  The networking.service is down.
                                        #  The systemd-networkd.service is up and running.

lsusb
ip address
sudo iwconfig

sudo ip link set dev wlxa0f3c12af53a up
sudo ip link set dev wlxa0f3c11850e5 up

sudo iwlist wlxa0f3c12af53a scan | grep ESSID
sudo iw dev wlxa0f3c12af53a scan | grep SSID

sudo iwlist wlxa0f3c11850e5 scan | grep ESSID
sudo iw dev wlxa0f3c11850e5 scan | grep SSID

# Private.
wpa_passphrase Private <password> | tee /tmp/wpa_supplicant-Private.conf
sudo wpa_supplicant -c /tmp/wpa_supplicant-Private.conf -i wlx00026fc8b97c                      # Not working.
sudo wpa_supplicant -c /tmp/wpa_supplicant-Private.conf -i wlxa0f3c11850e5                      # Not working.

# Guest.
file="/tmp/wpa_supplicant-Guest.conf"
cat << EOF | sed -e "s/^  //" > "${file}"
  network={
      ssid="Guest"
      group=CCMP TKIP
      key_mgmt=NONE
      scan_ssid=1
  }
EOF
sudo wpa_supplicant -c /tmp/wpa_supplicant-Guest.conf -i wlx00026fc8b97c                        # Not working.
sudo wpa_supplicant -Dnl80211,wext -c /tmp/wpa_supplicant-Guest.conf -i wlx00026fc8b97c         # Not working.

# 3BB.
wpa_passphrase 3bb-wlan <password> | tee /tmp/wpa_supplicant-3BB.conf
sudo wpa_supplicant -B -c /tmp/wpa_supplicant-3BB.conf -i wlx00026fc8b97c                       # Working.
sudo wpa_supplicant -B -c /tmp/wpa_supplicant-3BB.conf -i wlx00026fc8b97c -Dnl80211,wext
sudo wpa_supplicant -B -Dnl80211,wext -c /tmp/wpa_supplicant-3BB.conf -i wlx00026fc8b97c
sudo iwconfig wlx00026fc8b97c

ip address
sudo dhclient wlx00026fc8b97c

# Use square brackets around a character of the search pattern to exclude grep from ps command output.
pid="$(ps ax | grep -w "[w]pa_supplicant" | sed "s/ .*//")"
sudo kill -9 "${pid}"

sudo ip link set dev wlx00026fc8b97c down
sudo ip link set dev wlx788cb5ed6dc4 down

iface="wlx00026fc8b97c"
file="/etc/systemd/network/${iface}.network"
# Do not use single quotes around EOF to allow interpreting variables.
cat << EOF | sed -e "s/^  //" > "${file}"
  [Match]
  Name=${iface}

  [Network]
  DHCP=ipv4

  [DHCP]
  ClientIdentifier=mac
  RouteMetric=20
  UseDomains=yes
EOF

iface="wlx00026fc8b97c"
file="/etc/udev/rules.d/95-wireless.rules"
# See https://github.com/systemd/systemd/issues/2891
# Do not use single quotes around EOF to allow interpreting variables.
cat << EOF | sed -e "s/^  //" > "${file}"
  ACTION=="add", SUBSYSTEM=="net", KERNEL=="${iface}", TAG+="systemd", ENV{SYSTEMD_WANTS}="wpa_supplicant@${iface}.service"
EOF

file="/lib/systemd/system/wpa_supplicant@.service"
# Back up original file if backup file is missing.
if [ -f "${file}" ] && [ ! -f "${file}.org" ]; then cp -a "${file}" "${file}.org"; fi
# Modify file if modification is missing.
if ! grep -q "^ExecStartPre=/bin/dmesg --console-off$" "${file}"; then
  # Disable printing of messages to console.
  sed -i "/^ExecStart=/i ExecStartPre=/bin/dmesg --console-off" "${file}"
fi
# Modify file if modification is missing.
if ! grep -q "^ExecStartPre=/sbin/modprobe -r b43$" "${file}"; then
  sed -i "/^ExecStart=/i ExecStartPre=/sbin/modprobe -r b43" "${file}"
fi
# Modify file if modification is missing.
if ! grep -q "^ExecStartPre=/sbin/modprobe -r ssb$" "${file}"; then
  sed -i "/^ExecStart=/i ExecStartPre=/sbin/modprobe -r ssb" "${file}"
fi
# Modify file if modification is missing.
if ! grep -q "^ExecStartPre=/usr/sbin/rfkill unblock wifi$" "${file}"; then
  sed -i "/^ExecStart=/i ExecStartPre=/usr/sbin/rfkill unblock wifi" "${file}"
fi

# Create configuration file for wpa-roam mode.
iface="wlx00026fc8b97c"
file="/etc/wpa_supplicant/wpa_supplicant-${iface}.conf"
ssid1="Private"         # wap07smru
ssid2="Guest"
ssid3="3bb-wlan"        # 1111100000
ssid4="TOT"             # admin1234
# Generate WPA pre-shared key from 1st Wi-Fi SSID and 1st passphrase.
  psk1="$(wpa_passphrase "${ssid1}" "<password>" | grep "\spsk=" | sed "s/\spsk=//")"
# Generate WPA pre-shared key from 3rd Wi-Fi SSID and 3rd passphrase.
  psk3="$(wpa_passphrase "${ssid3}" "<password>" | grep "\spsk=" | sed "s/\spsk=//")"
# Generate WPA pre-shared key from 4th Wi-Fi SSID and 4th passphrase.
  psk4="$(wpa_passphrase "${ssid4}" "<password>" | grep "\spsk=" | sed "s/\spsk=//")"
# Note: The "scan_ssid=1" line is needed when the Wi-Fi does not broadcast its SSID.
# Do not use single quotes around EOF to allow interpreting variables.
cat << EOF | sed -e "s/^  //" | sudo tee "${file}"
  ######################## Global Configuration Options ########################

  country=TH
  ctrl_interface=DIR=/run/wpa_supplicant GROUP=netdev
  update_config=1

  ######################## Network Block Configurations ########################

  network={
    ssid="${ssid1}"
    group=CCMP TKIP
    key_mgmt=WPA-PSK
    pairwise=CCMP TKIP
    priority=1
    proto=WPA2
    psk=${psk1}
    scan_ssid=1
  }

  network={
    ssid="${ssid2}"
    group=CCMP TKIP
    key_mgmt=NONE
    scan_ssid=1
  }

  network={
    ssid="${ssid3}"
    group=CCMP TKIP
    key_mgmt=WPA-PSK
    pairwise=CCMP TKIP
    priority=3
    proto=WPA2
    psk=${psk3}
    scan_ssid=1
  }

  network={
    ssid="${ssid4}"
    group=CCMP TKIP
    key_mgmt=WPA-PSK
    pairwise=CCMP TKIP
    priority=4
    proto=WPA2
    psk=${psk4}
    scan_ssid=1
  }

EOF
sudo chmod 600 "${file}"

sudo wpa_supplicant -c /etc/wpa_supplicant/wpa_supplicant-wlx00026fc8b97c.conf -i wlx00026fc8b97c