List all indexes on ElasticSearch server?

Question

I would like to list all indexes present on an ElasticSearch server. I tried this:

curl -XGET localhost:9200/

but it just gives me this:

Answer 1

Accessing the Secured Elastic Search though Curl (Update 2020)

If the Elastic Search is secured, You can use this command to list indices

curl http://username:password@localhost:9200/_aliases?pretty=true