I gather that you're not using CGI.pm, then, since that first syntax you tried didn't work... if you were using CGI.pm, it would have worked.

    #!/usr/local/bin/perl -w
    use strict;

    use CGI;
    my $q = new CGI;

    print map $_ . " => " . $q->param($_) . "\n",
        $q->param;
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See:

    % foo.cgi foo=bar baz=quux
    foo => bar
    baz => quux
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So use CGI.pm. The alternative is to write your own code to emulate a CGI environment, reading parameters either from @ARGV or from STDIN. All of which work has already been done in CGI.pm.