How do I find out version of currently running Solr?

Please tell me how can I determine the version number of currently running solr ?

On the Solr Admin page click on [INFO]. The next screen will have the version.

(For me, the Solr admin page is located here: http://{host-name-or-ip}:{port}/solr/admin, I found I was dealing with an older version. Solr Specification Version: 1.4.0 Solr Implementation Version: 1.4.0 833479)

With a HTTP GET request to:

yoursolrhost:8983/solr/admin/info/system

you'll retrieve a structure in many different representations (xml, json, php, python,...).

the lucene key of the structure contains version numbers.

For example, using json output:

http://yoursolrhost:8983/solr/admin/info/system?wt=json

The lucene key looks like this:

"lucene": {
    "solr-spec-version": "4.6.0",
    "solr-impl-version": "4.6.0 1543363 - simon - 2013-11-19 11:16:33",
    "lucene-spec-version": "4.6.0",
    "lucene-impl-version": "4.6.0 1543363 - simon - 2013-11-19 11:05:50"
},

solr admin "infos" button links to "admin/registry.jsp"

so you can get the version with :

wget -O- "http://solr_ip_adress.lan:8080/solr/admin/registry.jsp" | grep 'solr-spec-version'

You could use http://localhost:8983/solr/admin/info/system?wt=json to gather the details and Solr version too.

Tested on Solr v6.6.0

You need to query Solr using the SystemInfoHandler:

http://lucene.apache.org/solr/api/org/apache/solr/handler/admin/SystemInfoHandler.html

You can simply go to your Solr Dashboard page as in URL

http://localhost:8983/solr

Assumption, you use version 3.6, port 8080. Go to http://localhost:8080/solr/default/admin/registry.jsp

You will see result:

Solr Implementation Version: 3.6.0 1310449 - rmuir - 2012-04-06 11:34:07

From the command line of a Linux server running solr:

sudo service solr status

Depending on your version of Linux, I imagine you might have to modify that to use systemctl instead of service, or other means of calling the solr service.