SSID表示WIFI名称，PASSWORD表示WIFI密码
初次联网
ifconfig wlan0 up
wpa_passphrase SSID PASSWORD >> /etc/wpa_supplicant.conf
wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf
sleep 2
iw wlan0 link
udhcpc -i wlan0
ping www.baidu.com -c 4
重启后联网
不必再次添加WI-FI热点信息
ifconfig wlan0 up
wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf
sleep 2
iw wlan0 link
udhcpc -i wlan0
ping www.baidu.com -c 4
连接失败
ifconfig wlan0 up
sleep 2
iw wlan0 link
udhcpc -i wlan0
ping www.baidu.com -c 4