You could look at cpan, for the modules:
Getopt::Std - The getopt() function processes single-character switches with switch clustering. Pass one argument which is a string containing all switches that take an argument. For each switch found, sets $opt_x (where x is the switch name) to the value of the argument if an argument is expected, or 1 otherwise. Switches which take an argument don't care whether there is a space between the switch and the argument.

The getopts() function is similar, but you should pass to it the list of all switches to be recognized. If unspecified switches are found on the command-line, the user will be warned that an unknown option was given.

Note that, if your code is running under the recommended use strict 'vars' pragma, you will need to declare these package variables with "our":

integer - Perl pragma to use integer arithmetic instead of floating point