Thx!

No, transmitter is only for commands supplied to the server, which help should not be (at least at the moment fail2ban server does not provide special command for help).

Maybe it was planned at some time point...
Just in newer versions (at least starting from some v.0.10.x), the protocol streams and help of fail2ban-client and fail2ban-server are the same, so I don't see why we'd need such command at server side.

thats not a bug, the display is uggly formatted. it clearly satys, that -h or --help is required.

@djdomi read the issue again. The bug is that fail2ban-client lists help command, but actually trying it leads to an error. It should either support the command properly or not list it.

it clearly satys, that -h or --help is required

Required for what? For help command? Sure, there you go:

$ fail2ban-client help -h
2022-05-27 10:08:19,868 fail2ban                [12195]: ERROR   NOK: ('Invalid command',)
Invalid command

@djdomi read the issue again. The bug is that fail2ban-client lists help command, but actually trying it leads to an error. It should either support the command properly or not list it.

it clearly satys, that -h or --help is required

Required for what? For help command? Sure, there you go:

$ fail2ban-client help -h
2022-05-27 10:08:19,868 fail2ban                [12195]: ERROR   NOK: ('Invalid command',)
Invalid command

i basically meaned

 -h, --help              display this help message

which leads to

fail2ban-client -h
fail2ban-client --help

which is (IMHO&AFAIK) the correct handling for basic Linux commands.

i basically, researched what you meaned, and i agree at one point to you:

help is shown as command, but not as action.

i am unfamilar with python, but it looks like a similar possibility like

 elif o in ("-h", "--help"): 

to be changed to

elif o in ("-h", "--help", "help"):

on bash it would work similar like this :-)