#!/usr/bin/perl -w
use strict;
my %d = map{
        #cleanup the line
        chomp;
        #does it match
        /^([\d\.]+) \w+/ ? ($1, $_) : ();
    }map{
        #use @ARGV and <> magic to 
        #read in each line from each file.
        local @ARGV = ($_);
        <>;
    }<SomeOutPut*.dat>; #glob in all files that match 

open(OUTPUT, ">unique.dat") or die "a horrible death... $!";
print OUTPUT, $d{$_}."\n" for(sort keys %d);
close OUTPUT;