use Getopt::Std;
getopts('fs', \%opts);

##</code><code>##

if ($opts{s}) { #do stuff }

##</code><code>##

Global symbol "%opts" requires explicit package name.....

##</code><code>##

{
    package FOO;
    use Getopt::Std;
    getopts('fs', \%opts);
}