This is a very simple pure Perl solution that will work also on Win32 machines; it is based on an associative array in order to kill duplicate entries. What's nice with it is that if you add to the printing loop $hDat{$d} you get to know how many times a line was repeated. 
use strict;
my %hDat;
my $d;

map( $hDat{$_}++, <DATA> );

foreach $d (sort keys %hDat) { print $d; }

__DATA__
a
b
c
dd
c
aa
zzzz
q
r

[download]
You could also use a similar approach to perform a case-insensitive duplicate line removal that returns the last instance of the duplicate line in the full majesty of its original case: 
use strict;
my %hDat;
my $d;

map( ($hDat{lc $_} = $_), <DATA> );

foreach $d (sort keys %hDat) { 
    print $hDat{$d}; 
}

__DATA__
a
Bongo
c
BoNgo
dd
c
A
zzzz
q
r

[download]

In reply to Re: Sorting Unique File Entries by l3nz
in thread Sorting Unique File Entries by Paulster2

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