How can I create a new tag in git?

git tag [newtag]
git push origin [newtag]

How can I delete remote tag in git?

git push --delete origin tagname

How can I create a new branch from a tag in git?

git checkout -b [newbranch] [tag]

How can I delete an index from Elasticsearch?

curl -XDELETE 'http://localhost:9200/[yourindexname]/'

How can I see/list all all record in Elasticsearch?

Lucene syntax:

 http://localhost:9200/foo/_search?pretty=true&q=*:*&size=[NUMBEROFRECORD]

Elasticsearch recommended:

curl -XGET 'localhost:9200/foo/_search?search_type=scan&scroll=10m&size=50' -d '
{
    "query" : {
        "match_all" : {}
    }
}'

How can I change server port of Spring Boot?

As a Jvm option:

 --server.port=8090