while ( my ($lk, $lv) = each %$loc_file ) {
    if ( !exists( $$rem_file{$lk} or $$rem_file{$lk < $lv ) {
      # do a put...
    }
    elsif ( $lv < $$rem_file{$lk} ) {
      # do a get...
    }
    delete $$rem_file{$lk}; # harmless if it's non-existent
  }

  # at this point, the only elements remaining in %$rem_file 
  # are files that do not exist on local host, so copy them all:

  for my $rk ( keys %$rem_file ) {
    # do a get...
  }