shell 获取本地主机指定网络接口的ip

源码：

get_local_ips.sh

#!/bin/bash

get_ip_from_device_index()
{
        index=$1
        sed_cmd="sed -ne '/^$((index)):/,/^$((index+1)):/p'"
        ip a|eval $sed_cmd|grep inet|awk '{ip=substr($2,1,index($2,"/")-1);print ip}'
}

get_index_from_device_name()
{
        name=$1
        sed_cmd="ip a|sed -ne '/^[0-9]:[ ]$name:/p'|cut -d: -f1"
        eval $sed_cmd
}

usage()
{
        cat<<-EOF
        echo usage: $0 <--name NAME|--index INDEX>
                --name:         network device name(eg. wlan0,eth0 etc.).
                --index:        network device index(could get it from command 'ip address').
        EOF
}

main()
{
        case $1 in
                --name)
                        device_name=$2
                        device_index=`get_index_from_device_name $device_name`
                        get_ip_from_device_index $device_index
                        ;;
                --index)
                        device_index=$2
                        get_ip_from_device_index $device_index
                        ;;
                *)
                        usage
                        ;;
        esac
}

main $@

注意：此脚本基于ip address命令的执行结果

使用举例：

比如，执行ip a命令后的结果如下：

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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: enp0s25: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
    link/ether 3c:97:0e:2d:bd:41 brd ff:ff:ff:ff:ff:ff
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether e0:06:e6:cc:ae:b3 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.112/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp3s0
       valid_lft 70129sec preferred_lft 70129sec
    inet6 fe80::c8fa:8f6b:cdf8:f34b/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
4: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 52:54:00:1b:42:84 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
6: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master virbr0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:59:58:85 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe59:5885/64 scope link 
       valid_lft forever preferred_lft forever

这些以（数字：）开头的行中，数字称作索引，数字后面即为接口名称

通过索引获取接口ip

比如:

./get-local-ips.sh --index 3

执行结果：

192.168.1.112
fe80::c8fa:8f6b:cdf8:f34b

通过名称获取接口ip

比如：

./get-local-ips.sh --name wlp3s0

执行结果同上。