Bulk upsert records to an org from a CSV file. Uses Bulk API 2.0.
Description for data upsert bulk
An upsert refers to inserting a record into a Salesforce object if the record doesn’t already exist, or updating it if it does exist.
When you execute this command, it starts a job, displays the ID, and then immediately returns control of the terminal to you by default. If you prefer to wait, set the –wait flag to the number of minutes; if it times out, the command outputs the IDs. Use the job and batch IDs to check the status of the job with the “sf data upsert resume” command.