optional
optional — Optional information.
Synopsis
optional ::= ![[-]](figs/web/nav/down.gif)
- Zero or more of:
- text
replaceable- Graphic inlines
- Indexing inlines
- Linking inlines
- Ubiquitous inlines
abbrevacronymaltanchorannotationbibliorefcorefdateemphasis(db._emphasis)firstterm(db._firstterm)footnotefootnoterefforeignphrase(db._foreignphrase)glossterm(db._glossterm)indexterm(db.indexterm.endofrange)indexterm(db.indexterm.singular)indexterm(db.indexterm.startofrange)inlinemediaobjectlinkolinkphrase(db._phrase)quote(db._quote)remarksubscriptsuperscripttrademarkwordaswordxref
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 ![[+]](figs/web/nav/right.gif)
This element occurs in 53 elements.
Children
This element contains 29 elements.
See Also
computeroutput, constant, literal, markup, option, parameter, prompt, replaceable, tag, userinput, varname
Examples
<article xmlns='http://docbook.org/ns/docbook'> <title>Example optional</title> <synopsis> ls <option>-abcCdfFgilLmnopqrRstux1</option> <optional>names</optional> </synopsis> </article>
ls -abcCdfFgilLmnopqrRstux1
names