kcadm.sh
Perform administration tasks from the command-line interface (CLI).
TLDR
Start an authenticated session
$ kcadm.sh config credentials --server [host] --realm [realm_name] --user [username] --password [password]
Create a user
$ kcadm.sh create users -s username=[username] -r [realm_name]
List all realms
$ kcadm.sh get realms
Update a realm with JSON config
$ kcadm.sh update realms/[realm_name] -f [path/to/file.json]