ElasticSearch is not to be used as your primary data store. It's a search tool and you should have a process to rebuild an index from your primary data store.
Outside of that, I highly recommend using a managed service, either AWS ElasticSearch service, or Elastic.co to make recovery and management easy. AWS does a snapshot on every index every couple hours and it's relatively simple to restore a deleted index.
Also, I'm sure the author knows this now, but don't ever run any command on a live production data store without triple checking it.
Elasticsearch provides some great tools to manage backups out of the box. It has built in snapshot functionality that sends incremental data snapshots to object storage or the file system for you and is really easy to setup.
You can use a tool like elasticsearch-curator or even cron to manage running backups or use the built in scheduling (snapshot lifecycle management)
Outside of that, I highly recommend using a managed service, either AWS ElasticSearch service, or Elastic.co to make recovery and management easy. AWS does a snapshot on every index every couple hours and it's relatively simple to restore a deleted index.
Also, I'm sure the author knows this now, but don't ever run any command on a live production data store without triple checking it.