Generate Subject Key Identifier by hand using openssl command sequence

From http://certificateerror.blogspot.se/2011/02/how-to-validate-subject-key-identifier.html.

Extract SKI from cert:

#!/bin/bash                                                                                                                                                             
openssl x509  -noout -in $1 -pubkey  | openssl asn1parse  -strparse 19 -out tmp.pub.der
openssl dgst -c -sha1 tmp.pub.der

Exctract SKI from key:

#!/bin/bash                                                                                                                                                             
openssl rsa -in $1  -pubout | openssl asn1parse -strparse 19 -out tmp.pub.der
openssl dgst -c -sha1 tmp.pub.der