You're using GetOpt.pl, which is deprecated. From the header:

# This library is no longer being maintained, and is included for back
+ward
# compatibility with Perl 4 programs which may require it.
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I think you'll be happier using Getopt::Std, which is part of the core distribution in 5.6. Getopt::Std provides and API for loading options into a hash, which can be lexically scoped using my.