cp -p from2/sub1/uno from3/sub1/dos from2/sub1/tres chk/sub1
cp -p from3/sub2/subby chk/sub2
+# Make sure that time has moved on.
+sleep 1
+
# Get rid of any directory-time differences
$RSYNC -av --existing -f 'exclude,! */' from1/ from2/
$RSYNC -av --existing -f 'exclude,! */' from2/ from3/