Probably the easiest way to explore your ElasticSearch cluster is to use elasticsearch-head.

You can install it by doing:

cd elasticsearch/
./bin/plugin -install mobz/elasticsearch-head

Then (assuming ElasticSearch is already running on your local machine), open a browser window to:

http://localhost:9200/_plugin/head/

Alternatively, you can just use curl from the command line, eg:

Check the mapping for an index:

curl -XGET 'http://127.0.0.1:9200/my_index/_mapping?pretty=1'

Get some sample docs:

curl -XGET 'http://127.0.0.1:9200/my_index/_search?pretty=1'

See the actual terms stored in a particular field (ie how that field has been analyzed):

curl -XGET 'http://127.0.0.1:9200/my_index/_search?pretty=1'  -d '
{
"facets" : {
"my_terms" : {
"terms" : {
"size" : 50,
"field" : "foo"
}
}
}
}

More available here: http://www.elasticsearch.org/guide

UPDATE : Sense plugin in Marvel

By far the easiest way of writing curl-style commands for Elasticsearch is the Sense plugin in Marvel.

It comes with source highlighting, pretty indenting and autocomplete.

Note: Sense was originally a standalone chrome plugin but is now part of the Marvel project.

ElasticSearch data browser

Search, charts, one-click setup....

Aggregation Solution

Solving the problem by grouping the data - DrTech's answer used facets in managing this but, will be deprecated according to Elasticsearch 1.0 reference.

Warning


Facets are deprecated and will be removed in a future release. You are encouraged to
migrate to aggregations instead.

Facets are replaced by aggregates - Introduced in an accessible manner in the Elasticsearch Guide - which loads an example into sense..

Short Solution

The solution is the same except aggregations require aggs instead of facets and with a count of 0 which sets limit to max integer - the example code requires the Marvel Plugin

# Basic aggregation
GET /houses/occupier/_search?search_type=count
{
"aggs" : {
"indexed_occupier_names" : {    <= Whatever you want this to be
"terms" : {
"field" : "first_name",    <= Name of the field you want to aggregate
"size" : 0
}
}
}
}

Full Solution

Here is the Sense code to test it out - example of a houses index, with an occupier type, and a field first_name:

DELETE /houses


# Index example docs
POST /houses/occupier/_bulk
{ "index": {}}
{ "first_name": "john" }
{ "index": {}}
{ "first_name": "john" }
{ "index": {}}
{ "first_name": "mark" }




# Basic aggregation
GET /houses/occupier/_search?search_type=count
{
"aggs" : {
"indexed_occupier_names" : {
"terms" : {
"field" : "first_name",
"size" : 0
}
}
}
}

Response

Response showing the relevant aggregation code. With two keys in the index, John and Mark.

    ....
"aggregations": {
"indexed_occupier_names": {
"buckets": [
{
"key": "john",
"doc_count": 2     <= 2 documents matching
},
{
"key": "mark",
"doc_count": 1     <= 1 document matching
}
]
}
}
....

A tool that helps me a lot to debug ElasticSearch is ElasticHQ. Basically, it is an HTML file with some JavaScript. No need to install anywhere, let alone in ES itself: just download it, unzip int and open the HTML file with a browser.

Not sure it is the best tool for ES heavy users. Yet, it is really practical to whoever is in a hurry to see the entries.

Absolutely the easiest way to see your indexed data is to view it in your browser. No downloads or installation needed.

I'm going to assume your elasticsearch host is http://127.0.0.1:9200.

Step 1

Navigate to http://127.0.0.1:9200/_cat/indices?v to list your indices. You'll see something like this:

Step 2

Try accessing the desired index: http://127.0.0.1:9200/products_development_20160517164519304

The output will look something like this:

Notice the aliases, meaning we can as well access the index at: http://127.0.0.1:9200/products_development

Step 3

Navigate to http://127.0.0.1:9200/products_development/_search?pretty to see your data:

If you are using Google Chrome then you can simply use this extension named as Sense it is also a tool if you use Marvel.

https://chrome.google.com/webstore/detail/sense-beta/lhjgkmllcaadmopgmanpapmpjgmfcfig

Following @JanKlimo example, on terminal all you have to do is:

to see all the Index: $ curl -XGET 'http://127.0.0.1:9200/_cat/indices?v'

to see content of Index products_development_20160517164519304: $ curl -XGET 'http://127.0.0.1:9200/products_development_20160517164519304/_search?pretty=1'

Kibana is also a good solution. It is a data visualization platform for Elastic.If installed it runs by default on port 5601.

Out of the many things it provides. It has "Dev Tools" where we can do your debugging.

For example you can check your available indexes here using the command

GET /_cat/indices