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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 -"

  • 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      

 #NETWORK private   

# NETWORK oracle internal 

# NETWORK oracle ext 
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What is the expected output? –  Thor Jan 3 '13 at 10:53

3 Answers 3

up vote 0 down vote accepted

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
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Not find duplicate IP try - this - echo "" > file echo "" >> file awk '/^[0-9 \.]+$/{ if(a[$0]++) print "Duplicate IP : ",$0;}' RS=" " file –  yael Jan 3 '13 at 10:47
updated the solution.. –  Guru Jan 3 '13 at 10:56

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 "" ) \
    | 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.

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try this:

cat config_IP.txt|egrep -v '^#|^$'|awk '{if($1==$2){print "Duplicate IP - "$1}}'
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isnt find duplicate IP , please try this echo "" > file , cat file |egrep -v '^#|^$'|awk '{if($1==$2){print "Duplicate IP - "$1}}' –  yael Jan 3 '13 at 10:34

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