optional
optional — Optional information.
Synopsis
- Zero or more of:
- text
phrase(db._phrase)replaceable- Graphic inlines
![[+]](figs/web/nav/right.gif)
- Indexing inlines
- Linking inlines
- Ubiquitous inlines
![[-]](figs/web/nav/down.gif)
Attributes
Description
The optional element indicates that a specified
argument, option, or other text is optional. The precise meaning of
“optional” varies according to the application or process
being documented.
Processing expectations
Formatted inline.
Optional arguments in a synopsis are usually
given special typographic treatment, and often they are surrounded by
square brackets. The optional tag is expected to
generate the brackets.
Outside a synopsis, the typographic treatment
of optional is application specific.
Parents
This element occurs in 51 elements.
Children
This element contains 16 elements.
See Also
computeroutput, constant, literal, markup, option, parameter, prompt, replaceable, tag, userinput, varname
Examples
1 <article xmlns='http://docbook.org/ns/docbook'> 2 <title>Example optional</title> 4 <synopsis> ls <option>-abcCdfFgilLmnopqrRstux1</option> 6 <optional>names</optional> </synopsis> 8 </article>
1
2 ls -abcCdfFgilLmnopqrRstux1
names