Set IP Address by using shell script on CentOS

You have a linux machine without GUI and you want to change its IP address? I was in this situation and spent few days to find way out. Now, I want to share this with you. You just copy and create your own shell script, that's all.



Create a bash script file

From command line, just type this then press Enter

$ vi setIP.sh

Copy and paste below scripts and save it

#!/bin/bash

#Usage: setIPHostName <ip> <netMask> <gateWay> <domainName> <domainIP>
get_prop(){ 
    propfile=$1
    key=$2
    grep  "^${2}=" ${1}| sed "s%${2}=\(.*\)%\1%"
}

ip=$1
netmask=$2
gateway=$3
domainname=$4
domainip=$5
hostname=$( cat /etc/hosts | grep 127.0.0.1 | awk '{ print $2 }' )
hostnameAlias=$( cat /etc/hosts | grep 127.0.0.1 | awk '{ print $3 }' )
uuid=`get_prop /etc/sysconfig/network-scripts/ifcfg-eth0 UUID`
hwaddr=`get_prop /etc/sysconfig/network-scripts/ifcfg-eth0 HWADDR`

checkVar ()
{

 echo ""
 echo "Variables to be set"
 echo IP = $ip
 echo NETMASK = $netmask
 echo GATEWAY = $gateway
 echo DOMAINNAME = $domainname
 echo DOMAINIP = $domainip
 echo HOSTNAME = $hostname
 echo HOSTNAME ALIAS = $hostnameAlias
 echo UUID = $uuid
 echo HWADDR = $hwaddr
 echo ""
 echo ""

}

setIpHostname ()
{
        # set hosts file
        echo "127.0.0.1 $hostname $hostnameAlias localhost" > /etc/hosts

        # set resolve.conf
        echo "search $domainname" > /etc/resolv.conf
        echo "nameserver $domainip" >> /etc/resolv.conf

        # set network file
        echo "NETWORKING=yes" > /etc/sysconfig/network
        echo "HOSTNAME=$hostname" >> /etc/sysconfig/network
 echo "GATEWAY=$gateway" >> /etc/sysconfig/network

        # set ifcfg-eth0
        echo "DEVICE=eth0" > /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "NAME=\"System eth0\"" > /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "BOOTPROTO=none" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "ONBOOT=yes" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "NETMASK=$netmask" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "IPADDR=$ip" >>  /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "GATEWAY=$gateway" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "TYPE=Ethernet" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "ONBOOT=yes" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "NM_CONTROLLED=yes" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "IPV4_FAILURE_FATAL=yes" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "IPV6INIT=no" >> /etc/sysconfig/network-scripts/ifcfg-eth0
        echo "DEFROUTE=yes" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "DOMAIN=$domainname" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "DNS1=$domainip" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "UUID=$uuid" >> /etc/sysconfig/network-scripts/ifcfg-eth0
 echo "HWADDR=$hwaddr" >> /etc/sysconfig/network-scripts/ifcfg-eth0
  
}

main ()
{
 setIpHostname
 # This VA so set it for every boot
 #cp /etc/hosts /root/
 #cp /etc/resolv.conf /root/
 #cp /etc/sysconfig/network /root/
 #cp /etc/sysconfig/network-scripts/ifcfg-eth0 /root/

 #{
  #echo "## Following line is added by ISV"
  #echo "cp /root/hosts /etc/hosts"
  #echo "cp /root/resolv.conf /etc/resolv.conf"
  #echo "cp /root/network /etc/sysconfig/network"
  #echo "cp /root/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0"
 #} >> /etc/rc.local

 echo "IP is changed. Rebooting..."
 #sleep 2
 #shutdown -r 1
 shutdown -r now
}

#checkVar
#setIpHostname
main

How to use
From command line, type this

$ ./setIP.sh     

For example

$ ./setIP.sh 192.168.1.241 192.168.1.254 255.255.255.0 google.com 8.8.8.8

NOTE: After run this script, your computer will be restart automatically. After your machine started, check your IP to make sure it is changed by command

$ ifconfig

Done!