D:\>set PERL5OPT= D:\>perl -MSYPH1 -MSYPH2 -e "" SYPH1.pm loaded D:\>perl -MSYPH1 -e "use SYPH2" SYPH1.pm loaded D:\>set PERL5OPT=-MSYPH1 D:\>perl -e "use SYPH2" SYPH1.pm loaded D:\>perl -MSYPH2 -e "" SYPH1.pm NOT loaded D:\>