The command-line client that we used to run the addUserWithFile command uses Jira's remote APIs to interact with Jira. Jira exposes many of its core functionalities via these APIs, such as the ability to create new users and issues.

When we run the addUserWithFile command, we pass in the CSV file that contains our new users, formatted in a way that the command-line client is able to understand and make an API call to Jira to create those users for us.

However, take note that the same security rules apply when using these remote APIs (with or without the command-line client). So in our case, since creating new users is an administrative task, we need to provide an administrator account in the command.

The Jira CLI app can do a lot more than just create users. Simply run jira.sh or jira.bat to see a full list of the commands and features it supports. The CLI Connector app installed in Jira provides many more additional remote APIs that will be used by some of the functions in the command-line client.