考题：取ifocnfig eth0 的ip地址
目标：192.168.1.200
[root@NFS ~]# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:50:56:33:66:20 inet addr:192.168.1.200 Bcast:192.168.1.255? Mask:255.255.255.0 inet6 addr: fe80::250:56ff:fe33:6620/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:62 errors:0 dropped:0 overruns:0 frame:0 TX packets:59 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:7676 (7.4 KiB) TX bytes:7967 (7.7 KiB)
思路：
目标之前的内容inet addr: 就用 ^.*addr:
目标结尾的内容Bcast:10.0.0.255 Mask:255.255.255.0 就用Bc.*$
解题过程：
#打印ip地址所在的行
[root@NFS ~]# ifconfig eth0|sed -n ‘2p’
inet addr:192.168.1.200? Bcast:192.168.1.255? Mask:255.255.255.0
#将以inet addr:开头的内容替换为空，即过滤掉
[root@NFS ~]# ifconfig eth0|sed -n ‘2s/^.*addr://gp’
192.168.1.200? Bcast:192.168.1.255 Mask:255.255.255.0
#将以Bcast:10.0.0.255 Mask:255.255.255.0结尾的内容替换为空，即过滤掉
[root@NFS ~]# ifconfig eth0|sed -n ‘2p’|sed ‘s/Bc.*$//g’
inet addr:192.168.1.200
#将前2个命令组合一下，就OK了
[root@NFS ~]# ifconfig eth0|sed -n ‘2s/^.*addr://gp’|sed ‘s/Bc.*$//g’
192.168.1.200
其他方法取ip地址，可以用cut实现
[teddylu@Web-02 ~]$ ifconfig eth0|grep ‘inet addr’|cut -d: -f2|cut -d” ” -f1
192.168.1.204
cut参数说明
-d, –delimiter=DELIM
use DELIM instead of TAB for field delimiter 指定分隔符
-f, –fields=LIST
select only these fields; also print any line that contains no delimiter character, unless the -s option is specified指定输出的域
解题的思路：
[teddylu@Web-02 ~]$ ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:D7:0C:6D
inet addr:192.168.1.204 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fed7:c6d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1866319 errors:0 dropped:0 overruns:0 frame:0
TX packets:136224 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2761798157 (2.5 GiB) TX bytes:15149581 (14.4 MiB)
[teddylu@Web-02 ~]$ /sbin/ifconfig eth1|grep ‘inet addr’
inet addr:10.0.0.204 Bcast:10.0.0.255 Mask:255.255.255.0
[teddylu@Web-02 ~]$ ifconfig eth0|grep ‘inet addr’|cut -d: -f2
192.168.1.204 Bcast
[teddylu@Web-02 ~]$ ifconfig eth0|grep ‘inet addr’|cut -d: -f2|cut -d” ” -f1
192.168.1.204
[root@dl-AN-S142 ~]# ifconfig|awk -F “[ :]+” ‘NR==2{print $4}’
172.19.63.93
其他方法(centos7):
[root@ilovelluvia re]# ifconfig eth0|grep -w inet|sed ‘s/inet//g’|awk -F” ” ‘{print $1}’
10.0.0.3