Hi Summer_Cherry,

Million thanks for giving me the piece of code which will comment starting from second occurance of matched pattern from the starting of line.

intelsol2>cat 1.txt
0152364|134444|10.20.30.40|015236433
0233654|122555|10.20.30.50|023365433
intelsol2>cat 2.txt
0152364|134444|10.20.30.40|015236433
0233654|122555|10.20.30.50|023365433
0789456|332211|10.20.30.40|078945633
1234567|225522|10.20.30.50|123456733
0321654|999999|10.20.30.40|032165433
0456123|777899|10.20.30.40|045612333
intelsol2>
nawk 'BEGIN{FS="|"}
{
if (NR==FNR)
a[$3]=0
else
{
a[$3]++
if (a[$3]>=2)
print "#"$0
else
print $0
}
}' 1.txt 2.txt >3.txt
intelsol2>cat 3.txt
0152364|134444|10.20.30.40|015236433
0233654|122555|10.20.30.50|023365433
#0789456|332211|10.20.30.40|078945633
#1234567|225522|10.20.30.50|123456733
#0321654|999999|10.20.30.40|032165433
#0456123|777899|10.20.30.40|045612333
intelsol2>

Also thanks a lot for unix forum guys "you ppl rock!!!"

FYI, i was trying to search for this code since all the weekend and went through sed manual "http://www.grymoire.com/Unix/Sed.html" sub topic (/1, /2, etc. Specifying which occurrence) however was unlucky in trying all the trial and error method.

Also Summer could you please explain me the code you have written so that i can understand it in a better way.

Again thanks a lot and you can close this thread.

Thanks
-imas