SubTest

Testing #sub function on IPFS URI:

URI: ipfs://bafybeiavz2kvaf4rfv7q46hxse4fk2tcqpzm4mgr67jbdqa2wpdarcie5y

sub 0,4: "ipfs"

sub 0,7: "ipfs://"

sub 7 onwards: "bafybeiavz2kvaf4rfv7q46hxse4fk2tcqpzm4mgr67jbdqa2wpdarcie5y"

ifeq test (0,4 = ipfs): YES MATCH

strlen test: 66