AWK - Hard to understand for me

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# 22  
OK in that case, try this:
awk -F\| '!/^#/ && !A[$4]++{print $4}' infile

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# 23  
Thank you sooo much Scrutinizer.

It has worked perfectly the way I wanted... kudos to you.

Can you please explain me the above command, I am bit new to awk.

Thanks Again, Ambar
# 24  
The difference with the earlier explanation given by itkamaraj is !A[$4]++ . This means if the value in array A of element is zero (if NOT (!) it is 1 or more) then perform the action in curly brackets. After the comparison the value of the element is incremented by 1, so the next time the same $4 is encountered later in the file, the expression evaluates to 0 (since the array element is not 1 and it is negated by the ! ), so the second time and any time after that, the action in curly brackets is not performed (in this case {print $4} )
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