shell获取本地网卡IP，mac，掩码，dns，外网IP

#/usr/bin/env bash

# Name: get_network_info.sh
# Author: Purple_Grape
# This is a script to gather network information of  your Linux system.
# Test under Ubuntu 10.04 only.

#----------------------------
NIC=eth0
MAC=`LANG=C ifconfig $NIC | awk '/HWaddr/{ print $5 }' `
IP=`LANG=C ifconfig $NIC | awk '/inet addr:/{ print $2 }' | awk -F: '{print $2 }'`
MASK=`LANG=C ifconfig $NIC | awk -F: '/Mask/{print $4}'`
ext_ip=`curl ifconfig.me`

if [ -f /etc/resolv.conf ];
then
     dns=`awk '/^nameserver/{print $2}' /etc/resolv.conf `
fi
#----------------------------
echo "Your network information is as below:"
echo $MAC
echo $IP
echo $dns
echo $ext_ip