hadoop jar --help and hadoop jar help commands show outputs like this:
Only if called with no arguments: hadoop jar we get the usage text, but even in that case we get:
Where RunJar is wrapped by the hadoop script (so it should not be displayed).
hadoop --help displays the following:
which is fine, but CommandsManual.md tells a bit more information about the usage of this command:
My suggestion is to add a --help option to the hadoop jar command that would display this message.