Resseting perl -M file mod after xx minutes

learningperl01 has asked for the wisdom of the Perl Monks concerning the following question:

Hello everyone, I was wondering if someone could please help as I am stuck with the following problem. I have this piece of code which I created to test the part that is not working properly. What I am trying to do is search for files in a directory and do something with them if they are older than xx amount of time. In the example below I am using the check of files that are > 3 minutes. The problem that I have come across or think what the problem is, is that if the file does not meet the -M "$path" > .0020 it will never match, since I am guessing that the check is done against the time the script was launched. So when the script goes to sleep to wait for the files to be xx amount of minutes old before doing something with them it never matches, even though the xx time has gone by making them xx minutes older. Is there anyway to reset the timer of -M or is there a better way to do this? thanks for the help in advance.

#!/usr/bin/perl
use strict;
use warnings;

my $DirPath = "/tmp//testing";

while ("true") {
    opendir (DIR, "$DirPath") or die "Cannot open $DirPath $!\n";
    my @Files = grep { !/^\.{1,2}$/ } readdir DIR;
    close DIR;
    if(scalar(@Files) > 1) {
        foreach my $File (@Files) {
            next unless (-f "$DirPath/$File");
            chomp $File;
            print $File, "\n";
            if ((-M "$DirPath/$File" > .0020)) {
                print "File: $File is older than 3 minutes\n";
            }
            else {
                print "File: $File is not older than 3 minutes\n";
            }
        }
    }
    else {
        print "Num of file required not met\n";
        sleep 10;
    }
}
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Comment on Resseting perl -M file mod after xx minutes Download Code

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Re: Resseting perl -M file mod after xx minutes by JavaFan (Canon) on Jul 10, 2009 at 16:16 UTC
`(stat "$DirPath/$File")[9] < time() - 180`	[reply] [d/l]
Re: Resseting perl -M file mod after xx minutes by elTriberium (Friar) on Jul 10, 2009 at 20:20 UTC
From "Programming Perl" page 100 (in my edition): To reset the script's start time to the current time, say this: `$^T = time;` [download]	[reply] [d/l]
Re: Resseting perl -M file mod after xx minutes by mzedeler (Pilgrim) on Jul 10, 2009 at 19:54 UTC
A completely different comment - hope its okay. What is the `if(scalar(@Files) > 1)` supposed to do? You're skipping all directories with just one entry, which one you skip depends on the file system.	[reply] [d/l]
Re^2: Resseting perl -M file mod after xx minutes by ikegami (Patriarch) on Jul 10, 2009 at 20:26 UTC
"All directories"? There's only one. "which one you skip depends on the file system."? That makes no sense. If there's only one, how can you choose from many, and how can the result of that choice depend on the file system.	[reply]
Re^3: Resseting perl -M file mod after xx minutes by mzedeler (Pilgrim) on Jul 10, 2009 at 21:33 UTC
What I mean is: all directories you run this script on that only contains one directory entry (besides current and parent dir) will not be processed. Sorry for being imprecise~~, but I believe my comment still applies~~. (Updated. Sigh!)	[reply]
Re^4: Resseting perl -M file mod after xx minutes by ikegami (Patriarch) on Jul 10, 2009 at 21:43 UTC
Re^5: Resseting perl -M file mod after xx minutes by mzedeler (Pilgrim) on Jul 12, 2009 at 20:48 UTC
Some notes below your chosen depth have not been shown here
Re^2: Resseting perl -M file mod after xx minutes by toolic (Bishop) on Jul 11, 2009 at 01:24 UTC
if(scalar(@Files) > 1) I agree that this code seems strange, and I will attempt to explain my reason with a concrete example. The OP is looking at files in a single directory, `$DirPath = "/tmp//testing";` (those double slashes look a little messy, but let's ignore that). Let's assume that the directory contains exactly 3 items the first time through the `while` loop: the 2 special dot directories (. and ..) and 1 file named foo.txt. The readdir will return a list of 3 items, and the grep will filter out the 2 directories. Thus, the `@Files` array will contain 1 item (the file foo.txt). Since `scalar(@Files)` resolves to 1, which is not greater than 1, the code enters the `else` clause and sleep's for 10 seconds. Therefore, there is no `-M` check on the foo.txt file during the first pass through the `while` loop because it is the only file in the directory. I doubt that is what the OP really wants. In fact, there will be no `-M` checks until there are at least 2 files in the directory, no matter how many 10 second intervals (and times throught the loop) elapse. Perhaps the OP has never encountered this corner case because there are always at least 2 files in the directory. Or maybe the OP just does not care about this case. But, it does seem strange to me. To avoid this corner case, `if(scalar(@Files) > 0)` could be used (or, more simply `if(@Files)`). Another reason the OP may never notice this case is if the directory contains at least 1 subdirectory. For example, if `$DirPath` contains a directory 'bar' in addition to file foo.txt, then the `@Files` array will contain 2 items (bar and foo.txt) after the grep/readdir. In this case, `if(scalar(@Files) > 1)` would be true, and the `-M` check would be preformed on the foo.txt file, but just as a happy accident. Again, I doubt that is what the OP really wants. If it were my code, I would filter out all directories with grep, not just the 2 special dot directories: `my @Files = grep { -f "$DirPath/$_" } readdir DIR;` [download]	[reply] [d/l] [select]
Re^3: Resseting perl -M file mod after xx minutes by mzedeler (Pilgrim) on Jul 12, 2009 at 20:51 UTC
Thanks for helping make the point. I tried and failed miserably - this is what I wanted to write.	[reply]