You are on the right track, but missing a couple of critical steps, which leaves you throwing out data that you don't want to throw out.

I'll walk through the first version you proposed, because I like it better (I personally find that style easier to read than the other one you mentioned, and it's also closer to being right):

opendir(LOGS,".");   
sort @val = map { -M $_ } grep(/.*\.log/,readdir(LOGS));
[download]

Problem one: sort returns a (sorted) list, which you're discarding. So *if* everything else were right (we'll get there), you would want

@val = sort map {-M $_} grep {...
[download]

To see the bigger problem, we break it down a bit more, working from right to left down that line:

@tmp1 = readdir LOGS;  
     # @tmp now contains the files listed in "."

@tmp2 = grep {/.*\.log/} @tmp1;
     #@ tmp2 now contains files that contain ".log"

@tmp3 = map {-M $_} @tmp2; 
     #@tmp3 now contains what?

@val = sort @tmp3;
[download]

If you re-read map, you'll discover that the list it generates is simply the result of the block {-M $_} applied to each value in @tmp2: since -M returns the age of the file, you now have a list of the ages of the log files in the directory, but *not* their names. Sort that list, and you have a sorted list of ages, but with no names associated with them. This is not what you wanted. :-)

What you *do* want is to associate age information with each of the items in @tmp1, sort on that, and get back the sorted version of @tmp1, which can be done thus:

use strict; #you are using strict, aren't you? ;)
my @val = map   { $_->[0] } 
          sort  { $a->[1] <=> $b->[1] }
          map   { [$_, -M $_] }
          grep  { /\.log$/ }
          readdir LOGS;
[download]

(assuming I didn't drop any critical concepts in there). You may note that I implemented chromatic's suggestion (well, almost) and tagged a $ into the regex to match the end of the file name (so "foo.logger" doesn't match).

This is what's known as a Schwartzian Transform, a term you may or may not have encountered here before. It is very useful. It is also slightly strange to the naked eye--if it makes instant sense to you, congratulations! And if not, take some time to work it out (there are a couple good explanations attached to that link) , because it's a cool technique.

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If God had meant us to fly, he would *never* have give us the railroads.
    --Michael Flanders

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