"tx" array inside blocks contains transactions hashes?
Read the fine manual!


  $ ./src/bitcoin-cli help getblock
  getblock "blockhash" ( verbosity )                                                                                                                                                                                  
  
  If verbosity is 0, returns a string that is serialized, hex-encoded data for block 'hash'.
  
  If verbosity is 1, returns an Object with information about block .
  
  If verbosity is 2, returns an Object with information about block  and information about each transaction.                                                                                                    


So if you add a 2 to the end of the RPC request, you'll get the full transaction contents rather than just the hash.