Explanation: userid is a required positional parameter specifying the identification of the user whose authority to issue any authorized command is to be changed. Authorized user commands are the storage administrator, operator, and system programmer commands.
For userid, substitute a string of one to seven alphanumeric characters for the identification of the user whose authorization is to be changed. The first character of the character string must be alphabetic or #, $, or @, and the remainder of the string can be alphanumeric and #, $, or @.