linux/solaris + verify duplicate valid IP address from file

Question

what the best way to find duplicate IP from file ( I have ksh script in this script I need to write function that check for duplicate IP )

for example if IP - 192.1926.23.52 exists twice in file - config_IP.txt then need to print "duplicate IP - xxx.xxx.xxx.xxx"

• solution can be with ksh or perl one liner , sed ,awk etc

the format of the file should be as the following:

more config_IP.txt

 # NETWORK adminstration


 192.192.23.150 192.192.23.120
 192.192.23.152 192.192.23.52      
 192.192.23.153 192.192.23.53      
 192.192.23.154 192.192.23.54      


 #NETWORK private

 192.192.23.170  192.192.23.122         
 192.192.23.172  192.192.23.126  
 192.192.23.174  192.192.23.123     
 192.192.23.177  192.192.23.121  



# NETWORK oracle internal


152.3.4.12 152.3.4.12 
152.3.4.14 152.3.4.16 


# NETWORK oracle ext

152.3.4.10 152.3.4.19 

Answer 1

Something like this (Assuming you want to check for IP against the entire file, not just against the one present in the same line):

awk '/^[0-9]/{for(i=1;i<=NF;i++)if(a[$i]++==1) print "Duplicate IP : ",$i;}' file

Answer 2

I'm not sure I understand the question correctly, but if you want to find duplicate IPs in a file like the one above, just put one IP per line then run it through sort and then uniq -c which will report the count of identical lines before each one:

cat config_IP.txt | sed "s/\s\s*/\n/g" | sort | uniq -c

If you want to check another IPs against the file, you can just group it with the cat:

( cat config_IP.txt; echo "12.34.56.78 90.101.121.131" ) \
    | sed "s/\s\s*/\n/g" | sort | uniq -c

You might also want to add some grep to filter out lines not containing IP addresses before you start sorting.

Answer 3

try this:

cat config_IP.txt|egrep -v '^#|^$'|awk '{if($1==$2){print "Duplicate IP - "$1}}'