Ok, I think I understand what you’re looking for a little better now. Use Getopt::Long:

#! perl
use strict;
use warnings;
use Getopt::Long;

my $L1 = '';
my $L2 = '';
my $p  = '';

GetOptions('L1=s' => \$L1, 'L2=s' => \$L2, p => \$p);

print "L1 switch: $L1\n";
print "p  switch: $p\n";
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as documented in Getopt::Long. Output:

16:39 >perl 698_SoPW.pl --L1 foo -p
L1 switch: foo
p  switch: 1

16:39 >
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But note that if there is no L2 switch defined here, --L (or even -l) will be accepted as an abbreviation for L1. From the documentation, it appears that this is a feature, not a bug: see Case and abbreviations.

Hope that helps,