utility will dump the kernel environment if
invoked without arguments.
option is specified, it will limit the report to kernel probe hints.
If an optional
name is specified,
will only report that value.
option is specified,
will delete the given environment variable.
If the environment variable is followed by an optional
will set the environment variable to this value.
option is set, warnings normally printed as a result of being unable to
perform the requested operation will be suppressed.