One line: 
ccn@laptop:~$ perl -lane '$H{$F[1].$F[3]}++ or print' file.txt
d1 c1.1  f1  d1.1
d1 c1.1  f2  d1.2
d5 c1.1  f4  d1.4
d6 c1.1  f5  d1.5
ccn@laptop:~$

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In reply to Re: Trying to remove duplicate rows using hashes by ccn
in thread Trying to remove duplicate rows using hashes by Angharad

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