X<PERL5OPT>
Command-line options (switches). Switches in this variable are taken
-as if they were on every Perl command line. Only the B<-[CDIMUdmtw]>
+as if they were on every Perl command line. Only the B<-[CDIMUdmtwW]>
switches are allowed. When running taint checks (because the program
was running setuid or setgid, or the B<-T> switch was used), this
variable is ignored. If PERL5OPT begins with B<-T>, tainting will be