WiFi設定 ( command line )

掃描ESSID

sudo iwlist wlan0 scan | grep -i ESSID

另一種命令列的方法：

https://askubuntu.com/questions/138472/how-do-i-connect-to-a-wpa-wifi-network-using-the-command-line

先修改/etc/wpa__supplicant/wpa_supplicant.conf權限

i@raspberrypi:/etc/wpa_supplicant $ ls -l
total 48
-rwxr-xr-x 1 root root   937 Sep 18  2016 action_wpa.sh
-rwxr-xr-x 1 root root 25892 Sep 18  2016 functions.sh
-rwxr-xr-x 1 root root  4696 Sep 18  2016 ifupdown.sh
-rw------- 1 root root   153 Apr 26 16:30 wpa_supplicant.conf
-rw------- 1 root root   153 Apr 26 16:05 wpa_supplicant.conf.backup
pi@raspberrypi:/etc/wpa_supplicant $ sudo chmod 777 wpa_supplicant.conf
pi@raspberrypi:/etc/wpa_supplicant $ ls -l
total 48
-rwxr-xr-x 1 root root   937 Sep 18  2016 action_wpa.sh
-rwxr-xr-x 1 root root 25892 Sep 18  2016 functions.sh
-rwxr-xr-x 1 root root  4696 Sep 18  2016 ifupdown.sh
-rwxrwxrwx 1 root root   153 Apr 26 16:30 wpa_supplicant.conf
-rw------- 1 root root   153 Apr 26 16:05 wpa_supplicant.conf.backup

透過wpa_passphrase指令寫入wifi參數

pi@raspberrypi:/etc/wpa_supplicant $ cat wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=GB

network={
    ssid="MySSID"
    psk="MyPassword"
    key_mgmt=WPA-PSK
}
pi@raspberrypi:/etc/wpa_supplicant $ sudo wpa_passphrase MyAnotherSSID MyAnotherPassword > /etc/wpa_supplicant/wpa_supplicant.conf
pi@raspberrypi:/etc/wpa_supplicant $ cat wpa_supplicant.conf
network={
    ssid="MyAnotherSSID"
    #psk="MyAnotherPassword"
    psk=b9cb1e33a09c3ee95055b37bca12f932d4f7ea36c44bfb8f958cf2c3f721afa7
}

編輯設定檔 wpa_supplicant.conf

sudo vim /etc/wpa_supplicant/wpa_supplicant.conf

參考這篇https://www.raspberrypi.com.tw/2152/setting-up-wifi-with-the-command-line/

土炮查WiFi訊號強度/品質

handy@handy-dell ~ $ cat /proc/net/wireless 
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
 wlan0: 0000   70.  -21.  -256        0      0      0     81   5552        0

或是

handy@handy-dell ~ $ iwconfig wlan0 | grep -i --color quality
          Link Quality=70/70  Signal level=-22 dBm

專業查WiFi訊號強度/品質

$sudo apt-get install wavemon

WiFi 開關

$sudo ifup wlan0
$sudo ifdown wlan0

WiFi 查SSID

$iwlist scanning | grep SSID