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4) Performing a Describe query on all consumer groups with a combination of options `--describe` and `--state` would allow us to grep consumer groups by their state (like `Stable, Dead, Empty, PreparingRebalance, NonExisting`). The only thing we have to do is to extend the "results table" with a GROUP column. 

5) Support new New CSV file format to export consumer offsets for multiple groups.

Public Interfaces

1) Providing the command line tool kafka-consumer-groups.sh with support of repeating --group parameter for operations --describe, --delete, --reset-offsets:

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