之前把自己电脑弄成双系统了，加了个centos7 服务器端。现在放假回家连不上家里的网络，各种着急啊。。
经过一番调查终于连上了，留个笔记以备后用，哈哈。
1、首先，切换到超级管理用户
[user@localhost]$ su root
2、检查当前可用的网卡，红色标记的就是网卡，这个并不是都是相同的
[root@localhost]$ iw dev
phy#0
Interface wlp2s0
ifindex 3
wdev 0x1
addr a4:db:30:84:4b:1c
type managed
以上是未连接网络的打印信息，如果已经连上则如下：
[root@localhost]# iw dev
phy#0
Interface wlp2s0
ifindex 3
wdev 0x1
addr a4:db:30:84:4b:1c
ssid liylr
type managed
channel 11 (2462 MHz), width: 40 MHz, center1: 2452 MHz
ssid就是广播信道名称，也就是你的无线网络信号，广播信道就是最后一个
3、查看连接前的初始状态
[root@ localhost]# ifconfig wlp2s0
wlp2s0: flags=4098 < BROADCAST,MULTICAST> mtu 1500
ether 60:d8:19:cc:74:84 txqueuelen 1000 (Ethernet)
RX packets 13547 bytes 13381624 (12.7 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 12659 bytes 1974514 (1.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
4、测试是否已经链接网络
[root@ localhost]# iw wlp2s0 link
Not connected.
5、获取SSID
[root@ localhost]# iw wlp2s0 scan | grep SSID
command failed: Network is down (-100)
无线网络未激活，先激活。
[root@ localhost]# ifconfig wlp2s0 up
[root@ localhost]# ifconfig wlp2s0
wlp2s0: flags=4099 < UP,BROADCAST,MULTICAST> mtu 1500
ether 60:d8:19:cc:74:84 txqueuelen 1000 (Ethernet)
RX packets 13547 bytes 13381624 (12.7 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 12659 bytes 1974514 (1.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
6、查看所有可用的无线网络信号
[root@localhost]# iw wlp2s0 scan | grep SSID
SSID: USER-20150101NS_Network_2
SSID: Tenda_17BEF8
SSID: PC-20140723DBVC_Network_1
SSID: 123
SSID: Tenda_0A6410
SSID: xiaohui
SSID: Tenda_51E4F0
SSID: Nobody Can
SSID: TP-LINK_3C479
7、连接无线网
[root@localhost]# wpa_supplicant -B -i wlp2s0 -c <(wpa_passphrase "Tenda_17BEF8" "useradmin")
Successfully initialized wpa_supplicant
Tenda_17BEF8是你想链接的SSID，useradmin为链接密码。
8、分配IP地址（通过dhclient控制网卡进行网络操作获取IP）
[root@localhost]# dhclient wlp2s0
9、最后，查看无线网卡地址信息，有ip地址表示网络连接成功了
[root@ localhost]# ifconfig wlp2s0
wlp2s0: flags=4163< UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.168.139 netmask 255.255.255.0 broadcast 192.168.168.255
inet6 fe80::62d8:19ff:fecc:7484 prefixlen 64 scopeid 0x20
ether 60:d8:19:cc:74:84 txqueuelen 1000 (Ethernet)
RX packets 13567 bytes 13386147 (12.7 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 12682 bytes 1979923 (1.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0