As others pointed out, it's good form to use YYYYMMDD. But in case you can't: 

#!/usr/bin/perl -w
use strict;

my $DIR = '.';

use File::Find              qw( find );
use File::Spec::Functions   qw( catfile );
use Time::Local             qw( timelocal );

my $todaysfile = catfile($DIR, time_to_filename(time));

if (! -e $todaysfile) {
  if (my $oldfile = find_latest_file($DIR)) {
    email_to_a_specific_person($oldfile);
  }
}

open FILE, ">>$todaysfile"
  or die qq{Can't open "$todaysfile": $!};
print FILE "Hello, World!\n";
close FILE;

exit 0;

sub find_latest_file
{
  my ($dir) = @_;

  my ($bestfile, $latest) = (undef, 0);

  find sub {
    my $time = filename_to_time($_) or return;
    if ($time > $latest) {
      ($bestfile, $latest) = ($File::Find::name, $time);
    }
  }, $dir;

  return $bestfile;
}

sub filename_to_time
{
  my ($filename) = @_;

  # Adjust if necessary
  my ($m, $d, $y) = $filename =~ /(\d\d)(\d\d)(\d\d)/
    or return;

  return timelocal(0, 0, 0, $d, $m - 1, $y);
}

sub time_to_filename
{
  my ($time) = @_;

  # Adjust if necessary
  my @localtime = localtime $time;
  my ($d, $m, $y) = @localtime[3, 4, 5];
  
  my $filename = sprintf("%02d%02d%02d.txt",
                         $m+1, $d, $y%100);
  return $filename;
}

sub email_to_a_specific_person
{
  my ($file) = @_;
  print "Sending $file . . .\n";
}

[download]

If you are planning on running more than one copy of the program at once, then this code will sometimes fail, and you will need to investigate file locking.

I should've used strftime() from POSIX and could've used reduce() from Scalar::Util. Note that find_latest_file() runs in O(n), which might make a difference (versus an n log n sort) after a few years.

In reply to Re: Find a file by TilRMan
in thread Find a file by Midnite

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