Automatic IP address modification using Shell scripts

As a Linux SA, scripts are used in many aspects of daily O & M, while Server ip addresses are generally bound to static ip addresses or MAC addresses. Of course, the latter is relatively cumbersome to operate, in the former, we can set the host name, ip address information, gateway, and other configurations. Modification to a specific host name is also convenient for maintenance and management. The following script is used to modify the ip address, host name, and other information as needed!

 
 

  
  
#! /Bin/sh
  
  
# Auto Change ip netmask gateway scripts
  
  
# Wugk 2012-12-17
  
  
Cat <EOF
  
  
++ Automatically modifies ip address, host name, and other related information.
  
  
ETHCONF =/etc/sysconfig/network-scripts/ifcfg-eth0
  
  
HOSTS =/etc/hosts
  
  
NETWORK =/etc/sysconfig/network
  
  
DIR =/data/backup/'date + % Y % m % d'
  
  
NETMASK = 255.255.255.0
  
  
+++ ++ ------------------------------- ++
  
  
EOF
  
  
# Define Path defines the variable, which can be modified according to the actual situation
  
  

  
  
ETHCONF =/etc/sysconfig/network-scripts/ifcfg-eth0
  
  
HOSTS =/etc/hosts
  
  
NETWORK =/etc/sysconfig/network
  
  
DIR =/data/backup/'date + % Y % m % d'
  
  
NETMASK = 255.255.255.0
  
  

  
  
Echo "============================================== =========="
  
  
Echo
  
  
# Define the change_ip Function
  
  
Function Change_ip ()
  
  
{
  
  
# Determine whether the backup directory exists. There are spaces before and after brackets ,! The exclamation point in shell indicates the opposite meaning #
  
  
If
  
  
[! -D $ DIR]; then
  
  

  
  
Mkdir-p $ DIR
  
  

  
  
Fi
  
  

  
  
Echo "Now Change ip address, Doing Backup Interface eth0"
  
  
Cp $ ETHCONF $ DIR
  
  

  
  
Grep "dhcp" $ ETHCONF
  
  
# $? Used to determine the status of the last operation. The value 0 indicates that the last operation is in correct or successful status #
  
  
If
  
  

  
  
[$? -Eq 0]; then
  
  
# Read-p Interactive input variable IPADDR. Note that there are spaces after the colon, sed-I modify the configuration file #
  
  
Read-p "Please insert ip Address:" IPADDR
  
  
Sed-I's/dhcp/static/G' $ ETHCONF
  
  
# Awk-F. It means to use the. Number to separate domains and print the first three columns #
  
  
Echo-e "IPADDR = $ IPADDR \ nNETMASK = $ NETMASK \ nGATEWAY = 'echo $ IPADDR | awk-F. '{print $1 ". "$2 ". "$3 }''. 254 ">>$ ETHCONF
  
  
Echo "This IP address Change success! "
  
  

  
  
Else
  
  

  
  
Echo-n "This $ ETHCONF is static exist, please ensure Change Yes or NO ":
  
  
Read I
  
  

  
  
Fi
  
  

  
  
If
  
  
["$ I" = "y"-o "$ I" = "yes"]; then
  
  
Read-p "Please insert ip Address:" IPADDR
  
  

  
  
Count = ('echo $ IPADDR | awk-F. '{print $1, $2, $3, $4 }'')
  
  
# Define an array. $ {# count [@]} indicates the total number of retrieved variable values #
  
  
A =$ {# count [@]}
  
  
# The while Condition Statement determines whether the number is correct. If the number is incorrect, the system prompts input in a loop. You can also use [0-9] to determine the ip address #
  
  
While
  
  

  
  
["$ A"-ne "4"]
  
  

  
  
Do
  
  

  
  
Read-p "Please re Inster ip Address, example 192.168.0.11 ip": IPADDR
  
  
Count = ('echo $ IPADDR | awk-F. '{print $1, $2, $3, $4 }'')
  
  
A =$ {# count [@]}
  
  

  
  
Done
  
  
# Sed-e can be used to modify multiple parameters continuously #
  
  
Sed-I-e's/^ IPADDR/# IPADDR/G'-e's/^ NETMASK/# NETMASK/G'-e's/^ GATEWAY/# GATEWAY/ g' $ ETHCONF
  
  
# Echo-e \ n is a continuous Append content with a line feed #
  
  
Echo-e "IPADDR = $ IPADDR \ nNETMASK = $ NETMASK \ nGATEWAY = 'echo $ IPADDR | awk-F. '{print $1 ". "$2 ". "$3 }''. 254 ">>$ ETHCONF
  
  
Echo "This IP address Change success! "
  
  
Else
  
  
Echo "This $ ETHCONF static exist, please exit"
  
  
Exit $?
  
  

  
  
Fi
  
  


  
  
}
  
  


  
  
# Define the hosts Function
  
  
########### Function hosts ##############
  
  
Function Change_hosts ()
  
  
{
  
  

  
  
If
  
  

  
  
[! -D $ DIR]; then
  
  
Mkdir-p $ DIR
  
  

  
  
Fi
  
  

  
  
Cp $ HOSTS $ DIR
  
  
Read-p "Please insert ip address": IPADDR
  
  

  
  
Host = 'echo $ IPADDR | sed's/\./-/G''
  
  
Cat $ HOSTS | grep 127.0.0.1 | grep "$ host"
  
  

  
  
If
  
  
[$? -Ne 0]; then
  
  
Sed-I "s/127.0.0.1/127.0.0.1 $ host/g" $ HOSTS
  
  
Echo "This hosts change success"
  
  

  
  
Else
  
  
Echo "This $ host IS Exist .........."
  
  

  
  
Fi
  
  

  
  
}
  
  

  
  
########## Fuction network ###############
  
  
# Define network functions
  
  
Function Change_network ()
  
  
{
  
  
If
  
  

  
  
[! -D $ DIR]; then
  
  
Mkdir-p $ DIR
  
  

  
  
Fi
  
  
Cp $ NETWORK $ DIR
  
  
Read-p "Please insert ip address": IPADDR
  
  

  
  
Host = 'echo $ IPADDR | sed's/\./-/G''
  
  
Grep "$ host" $ NETWORK
  
  

  
  
If
  
  
[$? -Ne 0]; then
  
  
Sed-I "s/^ HOSTNAME/# HOSTNAME/g" $ NETWORK
  
  
Echo "NETWORK = $ host"> $ NETWORK
  
  

  
  
Else
  
  
Echo "This $ host IS Exist .........."
  
  

  
  
Fi
  
  

  
  
}
  
  


  
  
# The PS3 is generally a menu prompt #
  
  
PS3 = "Please Select ip or hosts Menu ":
  
  
# Select command for the menu, in the format of select $ var in... command... do... done
  
  
Select I in "Change_ip" "Change_hosts" "Change_network"
  
  


  
  
Do
  
  
# Case method, generally used for judgment under multiple conditions
  
  
Case $ I in
  
  
Change_ip)
  
  
Change_ip
  
  
;;
  
  
Change_hosts)
  
  
Change_hosts
  
  
;;
  
  
Change_network)
  
  
Change_network
  
  
;;
  
  
*)
  
  
Echo
  
  
Echo "Please Insert $0: Change_ip (1) | Change_hosts (2) | Change_network (3 )"
  
  
Echo
  
  
;;
  
  
Esac
  
  


  
  
Done