Shell Programming and Scripting

# !/usr/bin/bash
#
# NoInterfaces
# Utility will create a file of ip addresses( file1) from an ARP file from network admin.
# Utility will create a file of interface ip addresses(file2) from an ARP file from network admin.
# Utility will create a file of user ip addresses(file3) from file1 and file2 created within utility
#

# set some variables
DIR=/export/home/gordonl
file1=$DIR/ipstrings     # Large file containing all arp ip strings
file2=$DIR/intfip        # small file containing interface ip strings
file3=$DIR/output.txt    # output file contains all of file1 - file2
# null the files
>$file1
>$file2
>$file3

# Locate all Internet IP Address strings from RtrARP
grep Internet $DIR/RtrARP | cut -d" " -f3 | sort -n -t . -k 1,1 -k 2,2 -k 3,3 -k 4,4 > $file1

# Locate all Router Interface strings
grep "ip address 1" $DIR/RtrARP | cut -d" " -f4 | sort -n -t . -k 1,1 -k 2,2 -k 3,3 -k 4,4 > $file2

while read HOST
do
   grep -v "$HOST" $file1 > $file3
done < $file2