KAFKA-2061 added the --version flag to kafka-run-class.sh which prints the Kafka version to the commandline.
As this is in kafka-run-class.sh this will effectively work for all commandline tools that use this file to run a class, so it should be added to the help output of these scripts as well. A quick grep leads me to these suspects:
Currently this parameter is not documented at all, neither in the output nor in the official docs.
I'd propose to add it to the docs as well as part of this issue, I'll look for a suitable place.