# purgeToMostRecent.pl purges files in a directory so all that remain are the n most recent.
# Written 30-jul-2004 by fgb.
#
# Modus: read folder & populate hash containing timestamp and filenames; sort by timestamp;
# then delete all but the top n files.

require "ctime.pl";
use Getopt::Long;
use Time::Local;

my $bDebug = 0;

my $sAppName = 'purgeToMostRecent';
my $sDate = &ctime(time); chop $sDate;
my $nDirsRead = 0;
my %files;
my $sFolder = '.';
#my $sFolder;
my $bHelp = 0;
my $i = 0;
my $nKeep = 3;					# default to 3 files
my $bListOnly = 0;
my $bVerbose = 0;
my $sVersion = "1.0";

$result = GetOptions('/|-','help|?'=>\$bHelp,'debug'=>\$bDebug,'list'=>\$bListOnly,'keep=i'=>\$nKeep,"dir=s"=>\$sFolder);

if (! $result) { errExit("can't process command line option(s)"); }

if ($bDebug) { $bVerbose = 1; $bListOnly = 1; print "dbg: debug ON\nkeep=$nKeep dir=$sFolder\n"; }
if ($bHelp) { help(); exit; }

MAIN:

processDir($sFolder);

# sort comparison operator <=> uses numeric instead of ascii sorting
# sort comparison function compares $b to $a for descending order

foreach $f (sort {$files{$b} <=> $files{$a}} keys %files) {
  ++$i;
  if ($bListOnly) { print "$f: $files{$f}"; 
    if ($i <= $nKeep) {  print " (keep)"; } else { print " (delete)"; }
    print "\n";
    }
  elsif ($i > $nKeep) { 
    unlink $f;
    if ($bVerbose) { print "deleted $f\n"; }
    }
  }

# subroutines:

sub errExit {
  $s = "Error: " . @_[0];

  print "$s\n";
  print "$sAppName terminated\n";
  exit;
  }

sub help {
  printf("%s version %s\n",$sAppName,$sVersion);
  print "Purges files in a directory so all that remain are the n most recent\n";
  print "\nusage: $sAppName [/dir=] [/keep=n] [/list]\n";
  print "\n/dir defaults to current default directory if not specified\n";
  print "/keep (# of files) value defaults to 3 if not specified\n";
  print "/list prints files which would be purged but does not delete them\n";
  }

sub processDir {
  local $sDir = $_[0];
  if (!length($sDir)) { return; }
  if ($sDir eq "..") { return; }

  print "processing folder $sDir...\n";

  if (!opendir(FLDR,$sDir)) { print "Can't open folder $sDir\n"; return; }
  ++$nDirsRead;
  local @filenames = readdir(FLDR);				# get list of files
  closedir(FLDR);
  foreach (@filenames) {
    if ($_ eq "." || $_ eq "..") { next; }
    $sFile = $sDir;
    if ($sDir !~ m/\\+$/) { $sFile .= "\\"; }			# if no \\ then add one
    $sFile .= $_;
    if ( -f $sFile) { &processFile($sFile); } 
    else { if ($bRecurse) { &processDir($sFile); } }
    }
  }

sub processFile {
  ($timestamp) = (stat($_[0]))[9];	# time last modified
#  if ($bDebug) {
#   ($jq,$jq,$jq,$dd,$mm,$yy,$jq,$jq,$jq) = localtime($timestamp);
#   $yy += 1900;
#   ++$mm;
#   print "dbg: $_[0] mod $mm-$dd-$yy\n"; 
#   }

  $files{$_[0]} = $timestamp;		# add to hash
  }

__END__