<arg choice='opt'>-b <replaceable>blocksize</replaceable></arg>
<arg choice='opt'>--header-fd <replaceable>fd</replaceable></arg>
<arg choice='opt'>--header-file <replaceable>filename</replaceable></arg>
<arg choice='opt'>-b <replaceable>blocksize</replaceable></arg>
<arg choice='opt'>--header-fd <replaceable>fd</replaceable></arg>
<arg choice='opt'>--header-file <replaceable>filename</replaceable></arg>