A string containing a pattern to be matched against command names, supporting * and ? wildcard characters. When this parameter is not specified, the default is *, to include all command names.
A list of the command names, formatted as:
(apropos command1 ... commandN)
on success, otherwise (error).
This command provides a list of all the commands available in the driver that match the pattern. If no pattern is given, it means the equivalent of *, and the list will contain all command names.