### First I read from database.

$data_path = "data/mixed.data";
open(DAT, $data_path) || die("Could not open file!");
@rawdata=<DAT>;
close(DAT); 
chomp @rawdata;  ## <<-- add this line here

##</code><code>##

###  Then I overwrite mixed.data with

$data_path = "data/mixed.data";

open(O, ">$data_path"); 
print O @scale;    ## <<-- don't use 'join "\n",...'
close(O);