getblockcount
Returns the height of the most-work fully-validated chain.
The genesis block has height 0.
Result:
n (numeric) The current block count
Examples:
> bitcoinII-cli getblockcount
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "getblockcount", "params": []}' -H 'content-type: text/plain;' http://127.0.0.1:8332/