With the unique method. @rows holds the rows and $s holds all unique elements from the rows.

#!/usr/bin/perl
use Set::Scalar;
my @rows;
while(<DATA>){
  my @q = split ' ';
  push @rows, Set::Scalar->new(@q);
}
my $s = Set::Scalar->new->unique(@rows);
__DATA__
1 3 4 5 6 
1 6 4 5 3 
1 2 4 
4 2 1
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