my @grp_advise = (
               		"normal,random,sequential",
               		"willneed,dontneed,free",
               		"access_lwp,access_many,access_default"
              );

for (my $grp_index = 0; $grp_index <= $#grp_advise; $grp_index++) {
        print "$grp_index  ===> $grp_advise[$grp_index]\n";

}