树莓派ubuntu20.04链接wifi

1. 查看wifi连接名

$ ls /sys/class/net

如果是ubuntu18或者20的话，该命令显示的应该有

eth0  lo  wlan0

其中wlan0为wifi的连接名

2. 编辑配置文件

$ cd /etc/netplan

在该目录下，如果是服务器，则会有一个05-cloud-init.yaml的文件，如果是桌面环境，会有一个01-network-manager-all.yaml

这里以05-cloud-init.yaml为例，编辑文件:

注意文件的缩进格式，

network:
  version: 2
  renderer: NetworkManager
  wifis:
    wlan0:
      dhcp4: true
      optional: true
      access-points:
        "你的wifi名称":
          password: "wifi密码"

看有的说还要安装wpasupplicant和network-manager，之前因为搞了那么就也没脸上，我也装了这个 

$ sudo apt-get install wpasupplicant
$ sudo apt-get install network-manager

3. 使文件生效

然后执行如下命令：

$ sudo netplan generate
$ sudo netplan apply

使用ifconfig -a查看连接情况：

看到wlan0中的inet，如果出现ip信息，则表示连接成功

eth0: flags=4099  mtu 1500
        ether xx:xx:xxx:xx:xx  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

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 208  bytes 16100 (16.1 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 208  bytes 16100 (16.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlan0: flags=4163  mtu 1500
        inet 192.168.2.192  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 xxxx:xxxx:xxxx:xxxx:xxxx  prefixlen 64  scopeid 0x0
        inet6 xxxx::xxxx:xxxx:xxxx:xxxx  prefixlen 64  scopeid 0x20
        ether b8:27:eb:f6:ea:8a  txqueuelen 1000  (Ethernet)
        RX packets 654  bytes 81544 (81.5 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 574  bytes 100354 (100.3 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0