The ">>" mode was used precisely because the file is constantly being reopened. But with your ++proposition, the preceding unlink can be removed, to let ">" overwrite the file instead.

Besides, the 3 args version of open with a scalar can be used for many reasons (elegance, safety ...) but at the very least for consistency with the way the input files are opened. 

my $output_file = "mergedlogs.txt";
open my $output_fh, ">", $output_file or die "Can't open $output_file:
+ $!";

{
  local $| = 0;
  local $\ = "\n"; # Automatically append \n
  foreach (@mergedlogs)
  {
    print $output_fh $_; # "$_\n" copies $_ into a new string before a
+ppending \n
  }
}

close $output_fh;

[download]
Although Corion's proposition to write the result straight to the file, without the @mergedlogs intermediate variable is probably a good idea as well.

In reply to Re^2: Write large array to file, very slow by Eily
in thread Write large array to file, very slow by junebob

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