2019-05-31 linux 使用 ip route 命令快速切换网关

工作中如果经常需要切换网关，可使用下面的脚本 方便切换

#!/bin/bash
# desc: change gateway in centos
# author: dbquan

ip_conf_file='/etc/sysconfig/network-scripts/ifcfg-eth0'
gw_arr=(1 2 3 205)
tips==$(echo ${gw_arr[@]} | sed "s/ /|/g")

# check gateway
check_gateway()
{
    now_gw=`grep "^GATEWAY=" $ip_conf_file`
    echo -e "\n===== now $now_gw ======\n"
    echo "please input a gatway: $tips"
    read in_gw

    if [ ! "$in_gw" ] || [[ ${gw_arr[@]/$in_gw/} = ${gw_arr[@]} ]]; then
        echo "[error:] please input gateway what you need to change to"
        echo "usage: $0 $tips"
        exit 1
    fi
}

# check gateway by command
check_gateway()
{
    now_gw=`ip route`
    echo -e "\n===== now $now_gw ======\n"
    echo "please input a gatway: $tips"
    read in_gw

    if [ ! "$in_gw" ] || [[ ${gw_arr[@]/$in_gw/} = ${gw_arr[@]} ]]; then
        echo "[error:] please input gateway what you need to change to"
        echo "usage: $0 $tips"
        exit 1
    fi
}

chg_gw_by_ip_route()
{
    echo -e "start to change \nfrom: $now_gw\n  to: GATEWAY=192.168.0.$in_gw"
    #sudo ip r del default && \
    #    sudo ip route add default via "192.168.0.$in_gw"
    # one line
    sudo ip r replace default via "192.168.0.$in_gw"
    if [ $? -eq 0 ]; then
        echo "succ"
    else
        echo "fail"
    fi
}

check_gateway && chg_gw_by_ip_route