open FILE, "data.txt" or die $!;          
while(<FILE>){
   chomp;                   

   my ($uniq,$one,$two,) = split ',';
                          # split the line into its fields

   $line_hash{$uniq} = qq($uniq $one $two);
                          # use a _unique_ key value
                          # describing the line to define
                          # a hash key, and splice the
                          # line to that key.
}
close FILE;                      
                          # now sort by the (presumed)
                          # numerical key, and print a test.

for( sort { $a <=> $b } keys %line_hash ){
    print "test: ",$line_hash{$_},$/ ;
}