Back-Referencing

When using the interactive CLI, a common scenario will be using an id from a previous result as the input to the next command. Back-referencing provides a shortcut for referencing a result from the previous command via a positional reference.

	Note
	Not every command produces back-references. To determine if a command supports back-referencing, check the usage.

#> registry list-buckets help
Lists the buckets that the current user has access to.
PRODUCES BACK-REFERENCES

A common scenario for utilizing back-references would be the following:

1. User starts by exploring the available buckets in a registry instance

   #> registry list-buckets
   #   Name           Id                                     Description
   -   ------------   ------------------------------------   -----------
   1   My Bucket      3c7b7467-0012-4d8f-a918-6aa42b6b9d39   (empty)
   2   Other Bucket   175fb557-43a2-4abb-871f-81a354f47bc2   (empty)

2. User then views the flows in one of the buckets using a back-reference to the bucket id from the previous result in position 1

   #> registry list-flows -b &1
   Using a positional back-reference for 'My Bucket'
   #   Name      Id                                     Description
   -   -------   ------------------------------------   ----------------
   1   My Flow   06acb207-d2f1-447f-85ed-9b8672fe6d30   This is my flow.

3. User then views the version of the flow using a back-reference to the flow id from the previous result in position 1

   #> registry list-flow-versions -f &1
   Using a positional back-reference for 'My Flow'
   Ver   Date                         Author                     Message
   ---   --------------------------   ------------------------   -------------------------------------
   1     Tue, Jan 23 2018 09:48 EST   anonymous                  This is the first version of my flow.

4. User deploys version 1 of the flow using back-references to the bucket and flow id from step 2

   #> nifi pg-import -b &1 -f &1 -fv 1
   Using a positional back-reference for 'My Bucket'
   Using a positional back-reference for 'My Flow'
   9bd157d4-0161-1000-b946-c1f9b1832efd

The reason step 4 was able to reference the results from step 2, is because the list-flow-versions command in step 3 does not produce back-references, so the results from step 2 are still available.