How to access HCatalog via REST interface in command line.

How to send request from command line - use netcat:
nc <host> <port>
and then type the request content:

GET <path>
Accept: application/json
ContentType: application/json

Let's bite the HCatalog via Rest interface then, first put request content in a file head.txt:

GET /templeton/v1/status
Accept: application/json
ContentType: application/json

Then send the request to the HCatalog web service - "what address and port, master" you may ask, well check it in HCatalog config file. In my case web service in running on default port (50111). While checking the port, note down HCatalog username you will need it later on.

echo head.txt | nc localhost 50111

You should get something like this:

{"status":"ok","version":"v1"}#

Now prepare for a mind-blowing experience change first line in head.txt to

GET /templeton/v1/ddl/database?user.name=hcat

To get information about databases for user hcat!

Let's go even deeper and check properties of given database:

GET /templeton/v1/ddl/database/<database_name>?user.name=hcat

To get tables from given database:

GET /templeton/v1/ddl/database/<database_name>/table?user.name=hcat

To check properties of given table:

GET /templeton/v1/ddl/database/<database_name>/table/<table_name>?user.name=hcat

That's all guys - thanks!