How to free up the space taken by bitcoind?
The quide you followed is 3 years old. Since then, there was an option added called prune - add it to a line in your bitcoind.conf, like so:


  prune=50000


And restart bitcoind. This would effectively limit your blockchain size to only 50Gb of recent blocks.

In case you need to have a full blockchain available for research &amp; analysis, there is no other way but to buy a bigger HD.

In case you don't need the local blockchain at all, then there is very little reason not to use a lightweight client like Electrum which does not store anything on your HD but instead relies on proprietary servers.