my @lines;

{
   local *FILE;

   open(FILE, "< filename.in")
   or die("Couln't open input file: $!\n");

   chomp(@lines = <FILE>);
}

my @sorted_lines = map { $_->[0]}
                   sort ( $a->[1] <=> $b->[1] }
                   map { [ $_, 0+$_ ] }
                   @lines;

{
   local *FILE;

   open(FILE, "> filename.out")
   or die("Couln't open output file: $!\n");

   local $, = "\n";
   print FILE (@lines);
}

Whats with the curly brackets? Here's what I have tried. It looks like the file is already ordered alphabetically by id when I used "du -ks *" but I need it by size which is the numbers. Here's my code, it doesnt seem to change the order.

#Push data into an array
die("Cannot open Log file to read from.")
	unless(open(TAKE, "<unix_list.txt"));	

while ($line = <TAKE>) {
	push(@list_all, $line);
}
close(TAKE);	

@list_all = sort { $a <=> $b } @list_all;

die("Cannot open Log file to write to.")
	unless(open(NEW, ">unix_list.txt"));

print NEW @lines;

close(NEW);