pruneblockchain "height"

The pruneblockchain RPC prunes the blockchain up to a specified height or timestamp.

*bitcoin-cli help pruneblockchain

pruneblockchain height

1. height    (numeric, required) The block height to prune up to. May be set to a discrete height, or to a UNIX epoch time
             to prune blocks whose block time is at least 2 hours older than the provided timestamp.

n    (numeric) Height of the last block pruned

> bitcoin-cli pruneblockchain 1000
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "pruneblockchain", "params": [1000]}' -H 'content-type: text/plain;'