操作系统：CentOS 7.0
使用场景：查看网卡IP地址
使用技巧：没有ifconfig命令，可以使用ip addr show/list查看，或是ip a
没有ifconfig命令，可以安装软件包net-tools;
使用经验：强烈建设使用ifconfig命令。
命令如：
ifconfig
ip addr show ip addr list ip a
上述两类命令的效果略有差别。
[sky9890@localhost ~]$ ifconfig
eth0: flags=4163
inet 192.168.153.128 netmask 255.255.255.0 broadcast 192.168.153.255
inet6 fe80::d84f:63df:d5a:2641 prefixlen 64 scopeid 0x20
ether 00:0c:29:65:85:ee txqueuelen 1000 (Ethernet)
RX packets 683 bytes 63920 (62.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 577 bytes 75167 (73.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 64 bytes 5568 (5.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 64 bytes 5568 (5.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[sky9890@localhost ~]$ ip a
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:
link/ether 00:0c:29:65:85:ee brd ff:ff:ff:ff:ff:ff
inet 192.168.153.128/24 brd 192.168.153.255 scope global noprefixroute dynamic eth0
valid_lft 1015sec preferred_lft 1015sec
inet6 fe80::d84f:63df:d5a:2641/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[sky9890@localhost ~]$ ip addr show
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:
link/ether 00:0c:29:65:85:ee brd ff:ff:ff:ff:ff:ff
inet 192.168.153.128/24 brd 192.168.153.255 scope global noprefixroute dynamic eth0
valid_lft 997sec preferred_lft 997sec
inet6 fe80::d84f:63df:d5a:2641/64 scope link noprefixroute
valid_lft forever preferred_lft forever