To display help on the imqusermgr command, use the -h option, and do not use a subcommand. You cannot get help about specific subcommands.
For example, the following command displays help about imqusermgr:
If you enter an imqusermgr command line containing the -h option in addition to a subcommand or other options, the Command utility processes only the -h option. All other items on the command line are ignored.