#!/usr/bin/perl
#
# upgrade thatdir [thisdir]
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -#
# This scans thisdir (.  by default), and for each file found,  checks #
# to  see  whether  the  corresponding  file  in thatdir exists and is #
# newer.  If so, the one in thatdir is copied over the one in thisdir. #
# Note  that  the direction of copy is thatdir -> thisdir; this is the #
# same order that the cp/mv/ln and the cptree/lntree commands use.     #
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -#

$usage = "$0: thatdir [thisdir]\n";

$thatdir = $ARGV[0] || die $usage;
$thisdir = $ARGV[1] || '.';

open(F,"find $thisdir -type f -print |")
	|| die "$0: Can't run find command.\n";

while ($f = <F>) {
	chop $f;
	$f =~ s#^$thisdir/##;
	$thisfile = "$thisdir/$f";
	$thatfile = "$thatdir/$f";
	if ( -f "$thatfile") {
		@thatstat = stat("$thatfile");
		@thisstat = stat("$thisfile");	# Missing files get zeroes.
		$thattime = $thatstat[9];
		$thistime = $thisstat[9];
		if ($thattime > $thistime) {
			print "$thatfile $thattime newer than $thisfile $thistime\n";
			system "Cp $thatfile $thisfile";
#		} else {
#			print "$thatfile $thattime older than $thisfile $thistime\n";
		}
	}
}