shell判斷網卡是否連接網絡

這個還是因爲樹莓派纔出現的, 直接上代碼

#!/bin/bash
#===============================================================================
#
#          FILE: is_network.sh
# 
#         USAGE: ./is_network.sh 
# 
#   DESCRIPTION: 
# 
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Yehun (), [email protected]
#  ORGANIZATION: Yehun
#       CREATED: 03/04/2018 07:58:08 PM
#      REVISION:  ---
#===============================================================================

ETH0_STATE=`cat /sys/class/net/eth0/operstate`
WLAN0_STATE=`cat /sys/class/net/wlan0/operstate`

if [ "up" == $ETH0_STATE ]; then
    echo "eth0 is network"
fi

if [ "up" == $WLAN0_STATE ]; then
    echo "wlan0 is network"
fi