This is easy to do with a hash. Open the file, read in one line at a time and use the split function to put the first element in each line (i.e. the filename) into a variable like $fn. If your hash is called %uniquefiles you then set the value for $fn to some arbitrary value, like

$uniquefiles{$fn} = 1;

If your loop comes across the same filename again, it will simply set the same value for the same filename, in effect eliminating the dupes. When you're all done %uniquefiles will only contain the unique filenames, which you can print like so:

foreach my $k (keys %uniquefiles) {
   print OUT "$k\n";
}

[download]
If you're just learning Perl, make sure you learn about hashes. They're a very powerful feature.

Steve

In reply to Re: output unique lines only by cormanaz
in thread output unique lines only by sbp

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