Raspberry pi2にUSB WiFiを設定した記録

 $ uname -a
Linux raspberrypi 5.4.79-v7+ #1373 SMP Mon Nov 23 13:22:33 GMT 2020 armv7l GNU/Linux

dmesg
[456806.044985] usb 1-1.3: Product: 802.11n NIC
[456806.045002] usb 1-1.3: Manufacturer: Realtek
[456806.045018] usb 1-1.3: SerialNumber: 00E04C0001
[456806.313635] lib80211: common routines for IEEE802.11 drivers

lsusb
Bus 001 Device 004: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
Bus 001 Device 006: ID 0bda:8179 Realtek Semiconductor Corp. RTL8188EUS 802.11n Wireless Network Adapter
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

iwconfig
wlan0     unassociated  ESSID:""  Nickname:"<WIFI@REALTEK>"
          Mode:Auto  Frequency=2.412 GHz  Access Point: Not-Associated
          Sensitivity:0/0
          Retry:off   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality:0  Signal level:0  Noise level:0
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

wlan0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 00:00:00:12:cb:3b  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

sudo apt install -y network-manager

# デバイスの認識状況
nmcli d | grep wifi
wlan0   wifi      disconnected  --

# 受信状況の確認
sudo iwlist wlan0 scan | grep ESSID
                    ESSID:"aterm-123456-g"
                    ESSID:"!Setup-G-317C"
                    ESSID:"WXHM_N31_a59733-g"

--- OR ---

# 受信状況の確認
nmcli dev wifi
IN-USE  SSID               MODE   CHAN  RATE       SIGNAL  BARS  SECURITY
        aterm-123456-g     Infra  9     44 Mbit/s  56      ***   WPA1 WPA2
        !Setup-G-317C      Infra  1     44 Mbit/s  42      **    --
        WXHM_N31_a59733-g  Infra  11    16 Mbit/s  26      *     WPA1 WPA2

wpa_passphrase Your_SSID Your_Passphrase

以下の内容を/etc/wpa_supplicant/wpa_supplicant.confに貼り付け
network={
	ssid="aterm-99999-g"
	#psk="password"
	psk=a95ba6a273a2c753185ca2269df798a3b0041a380ccb76d2aeeba2e42711849f
}

sudo vi /etc/wpa_supplicant/wpa_supplicant.conf

# WiFi起動
sudo ifup wlan0

--- OR ---

sudo /etc/init.d/networking restart

# 確認
iwconfig
wlan0     IEEE 802.11bgn  ESSID:"aterm-123456-g"  Nickname:"<WIFI@REALTEK>"
          Mode:Managed  Frequency:2.452 GHz  Access Point: 00:00:00:31:F1:3A
          Bit Rate:72.2 Mb/s   Sensitivity:0/0
          Retry:off   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=94/100  Signal level=66/100  Noise level=0/100
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0