Also, looking at the gencert.sh file (https://github.com/frntn/x509-san/blob/686f0468/gencert.sh) we can see it also uses a oneliner with process substitution.
(may be unrelevant but that kind of nice too)
24 karma · joined January 28, 2015
We should also notify the differences : I have compared both and have noticed your oneliner generates a CA certificate (which may not be what we want). Also the oneliner rely on the /etc/ssl/openssl.conf file which can change over the time, so the generated certificate may be affected too