run(open => './path/to/', do=> 'tell what to do', save => './path1/to');

##</code><code>##


sub run{
my ($self,%arg) = @_;

if (defined $arg{open}){
   $self->_open_it_and_run_it(open => $arg{open});
}
}

##</code><code>##

sub _open_it_and_run_it{
my ($self,%arg) = @_;
 open (IN, "<",$arg{open}) || die "$!";
 while (<IN>){
   ...
 }
 close IN:
}

##</code><code>##

run(open =>'./', ....);

##</code><code>##

run(open =>'./dir/', ....);