Print out a usage message.
-=item B<-CAfile> I<file>, B<-no-CAfile>, B<-CApath> I<dir>, B<-no-CApath>
-
-See L<openssl(1)/Trusted Certificate Options> for more information.
-
=item B<-CRLfile> I<file>
The I<file> should contain one or more CRLs in PEM format.
=item B<-crl_download>
-Attempt to download CRL information for this certificate.
+Attempt to download CRL information for certificates via their CDP entries.
=item B<-show_chain>
=item B<-trusted> I<file>
-A file of trusted certificates.
+A file of trusted certificates in PEM format.
+This option can be specified more than once to load certificates from multiple
+I<file>s.
=item B<-untrusted> I<file>
-A file of untrusted certificates.
+A file of untrusted certificates in PEM format to use for chain building.
+This option can be specified more than once to load certificates from multiple
+I<file>s.
+
=item B<-vfyopt> I<nm>:I<v>