use Getopt::Long;
Getopt::Long::Configure('bundling');

my %options;
GetOptions(
  \%options,
  'LongName|L=s'
);

if ($options{LongName}) {
  # do something with $options{LongName}
}

##</code><code>##

prog.pl --longname something

##</code><code>##

prog.pl -L something