#!/usr/bin/perl

use strict;

# create monthly tar files from a directory full of *.eml files

my %opties =
    (
    'filedir', '/usr/local/assp/spam',
    'archdir', '/usr/mail/tar',
    'fext', '\.eml$'
    );

chdir $opties{filedir};

my ( %files, %tarsets );
# %files: keys = file names; values = file modification date
# %tarsets: keys are "YYYYMM", values are lists of data file names

opendir D, ".";
for ( grep /$opties{fext}/, readdir D ) {
   $files{$_} = $^T - ((-M)*24*3600);
# convert file age to seconds, subtract from $^T to get file mod.date,
}
closedir D;

for my $f ( keys %files )
{
# use localtime to get month, year of modification:
   my ($m,$y) = (localtime($files{$f}))[4,5];
   my $ym = sprintf( "%d%02d", $y+1900, $m+1 );
   $tarsets{$ym} .= "$f\n";
}

# run tar with "--files-from -" and print file name list to it thru a pipe

$|++;
for my $d ( sort keys %tarsets )
{
   print "makeing tar file for $d...";
   open T, "| tar --create --file $opties{archdir}/$d.tar --files-from -" 
       or die "can't run tar for $d: $!";
   print T $tarsets{$d};
   close T;
   print "done\n";
}