Bitcoind linux disk usage
The blockchain is around 30 gigabytes. Unfortunately, if you want to use a full node client like bitcoind, you need all of that data. It's possible to prune the blockchain to just the unspent transactions, but the core devs have not implemented this yet on bitcoind. So no, you can't reduce the blockchain size as you need all of that data for a properly running bitcoind.

There are alternatives like electrum which use something called SPV to make the footprint of the application much smaller. This does require that you trust electrum servers, but it's very hard to fake that data, so it's fairly safe.