getblockcount
Returns the number of blocks in the longest blockchain.
Result:
n (numeric) The current block count
Examples:
> bitcoin-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/