To emphasize a particular word or phrase, use
emphasis. This may be presented as
italic, or bold, or might be spoken differently with a
text-to-speech system.
There is no way to change the presentation of the
emphasis within the document, no equivalent of
HTML's b and
i. If the information being presented is
important, then consider presenting it in
important rather than
emphasis.
emphasis ExampleUsage:
<para>&os; is without doubt<emphasis>the</emphasis>premiere &unix;-like operating system for the Intel architecture.</para>
Appearance:
FreeBSD is without doubt the premiere UNIX®-like operating system for the Intel architecture.
Many computer terms are acronyms,
words formed from the first letter of each word in a
phrase. Acronyms are marked up into
acronym elements. It is helpful to the
reader when an acronym is defined on the first use, as shown
in the example below.
acronym ExampleUsage:
<para>Request For Comments (<acronym>RFC</acronym>) 1149 defined the use of avian carriers for transmission of Internet Protocol (<acronym>IP</acronym>) data. The quantity of<acronym>IP</acronym>data currently transmitted in that manner is unknown.</para>
Appearance:
Request For Comments (RFC) 1149 defined the use of avian carriers for transmission of Internet Protocol (IP) data. The quantity of IP data currently transmitted in that manner is unknown.
To quote text from another document or source, or to
denote a phrase that is used figuratively, use
quote. Most of the markup tags available
for normal text are also available from within a
quote.
quote ExampleUsage:
<para>However, make sure that the search does not go beyond the<quote>boundary between local and public administration</quote>, as<acronym>RFC</acronym>1535 calls it.</para>
Appearance:
However, make sure that the search does not go beyond the “boundary between local and public administration”, as RFC 1535 calls it.
To refer to a specific key on the keyboard, use
keycap. To refer to a mouse button, use
mousebutton. And to refer to
combinations of key presses or mouse clicks, wrap them all
in keycombo.
keycombo has an attribute called
action, which may be one of
click, double-click,
other, press,
seq, or simul. The
last two values denote whether the keys or buttons should be
pressed in sequence, or simultaneously.
The stylesheets automatically add any connecting
symbols, such as +, between the key
names, when wrapped in keycombo.
Usage:
<para>To switch to the second virtual terminal, press<keycombo action="simul"><keycap>Alt</keycap><keycap>F1</keycap></keycombo>.</para><para>To exit<command>vi</command>without saving changes, type<keycombo action="seq"><keycap>Esc</keycap><keycap>:</keycap><keycap>q</keycap><keycap>!</keycap></keycombo>.</para><para>My window manager is configured so that<keycombo action="simul"><keycap>Alt</keycap><mousebutton>right</mousebutton></keycombo>mouse button is used to move windows.</para>
Appearance:
To switch to the second virtual terminal, press Alt+F1.
To exit vi without saving changes,
type Esc : q !.
My window manager is configured so that Alt+ mouse button is used to move windows.
Both applications and commands are frequently referred to when writing documentation. The distinction between them is that an application is the name of a program or suite of programs that fulfill a particular task. A command is the filename of a program that the user can type and run at a command line.
It is often necessary to show some of the options that a command might take.
Finally, it is often useful to list a command with its manual section number, in the “command(number)” format so common in Unix manuals.
Mark up application names with
application.
To list a command with its manual section
number (which should be most of the time) the DocBook
element is citerefentry. This will
contain a further two elements,
refentrytitle and
manvolnum. The content of
refentrytitle is the name of the command,
and the content of manvolnum is the
manual page section.
This can be cumbersome to write, and so a series of
general
entities have been created to make this easier.
Each entity takes the form
&man..manual-page.manual-section;
The file that contains these entities is in
doc/share/xml/man-refs.ent, and can be
referred to using this FPI:
PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"
Therefore, the introduction to FreeBSD documentation will usually include this:
<!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [ <!ENTITY % man PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"> %man; … ]>
Use command to include a command
name “in-line” but present it as something the
user should type.
Use option to mark up the options
which will be passed to a command.
When referring to the same command multiple times in
close proximity, it is preferred to use the
&man.
notation to markup the first reference and use
command.section;command to markup subsequent references.
This makes the generated output, especially
HTML, appear visually better.
Usage:
<para><application>Sendmail</application>is the most widely used Unix mail application.<para><para><application>Sendmail</application>includes the<citerefentry><refentrytitle>sendmail</refentrytitle><manvolnum>8</manvolnum></citerefentry>, &man.mailq.1;, and &man.newaliases.1; programs.</para><para>One of the command line parameters to<citerefentry><refentrytitle>sendmail</refentrytitle><manvolnum>8</manvolnum></citerefentry>,<option>-bp</option>, will display the current status of messages in the mail queue. Check this on the command line by running<command>sendmail -bp</command>.</para>
Appearance:
Sendmail is the most widely used Unix mail application.
Sendmail includes the sendmail(8), mailq(1), and newaliases(1) programs.
One of the command line parameters to
sendmail(8), -bp, will display the
current status of messages in the mail queue. Check this
on the command line by running
sendmail -bp.
Notice how the
&man.
notation is easier to follow.command.section;
To refer to the name of a file, a directory, a file
extension, or a device name, use filename.
filename ExampleUsage:
<para>The source for the Handbook in English is found in<filename>/usr/doc/en_US.ISO8859-1/books/handbook/</filename>. The main file is called<filename>book.xml</filename>. There is also a<filename>Makefile</filename>and a number of files with a<filename>.ent</filename>extension.</para><para><filename>kbd0</filename>is the first keyboard detected by the system, and appears in<filename>/dev</filename>.</para>
Appearance:
The source for the Handbook in English is found in
/usr/doc/en_US.ISO8859-1/books/handbook/.
The main file is called book.xml.
There is also a Makefile and a number
of files with a .ent extension.
kbd0 is the first keyboard detected
by the system, and appears in
/dev.
These elements are part of the FreeBSD extension to DocBook, and do not exist in the original DocBook DTD.
To include the name of a program from the FreeBSD
Ports Collection in the document, use the package
tag. Since the Ports Collection can be installed in any
number of locations, only include the category and the port
name; do not include /usr/ports.
By default, package refers to a binary package.
To refer to a port that will be built from source, set the
role attribute to
port.
package ExampleUsage:
<para>Install the<package>net/wireshark</package>binary package to view network traffic.</para><para><package role="port">net/wireshark</package>can also be built and installed from the Ports Collection.</para>
Appearance:
Install the net/wireshark binary package to view network traffic.
net/wireshark can also be built and installed from the Ports Collection.
These elements are part of the FreeBSD extension to DocBook, and do not exist in the original DocBook DTD.
Information for “system items” is marked up
with systemitem. The class
attribute is used to identify the particular type of
information shown.
class="domainname"The text is a domain name, such as
FreeBSD.org or
ngo.org.uk. There is no hostname
component.
class="etheraddress"The text is an Ethernet MAC address, expressed as a series of 2 digit hexadecimal numbers separated by colons.
class="fqdomainname"The text is a Fully Qualified Domain Name, with both hostname and domain name parts.
class="ipaddress"The text is an IP address, probably expressed as a dotted quad.
class="netmask"The text is a network mask, which might be
expressed as a dotted quad, a hexadecimal string, or as
a / followed by a number
(CIDR notation).
class="systemname"With class="systemname"
the marked up information is the simple hostname, such
as freefall or
wcarchive.
class="username"The text is a username, like
root.
class="groupname"The text is a groupname, like
wheel.
systemitem and Classes ExampleUsage:
<para>The local machine can always be referred to by the name<systemitem class="systemname">localhost</systemitem>, which will have the IP address<systemitem class="ipaddress">127.0.0.1</systemitem>.</para><para>The<systemitem class="domainname">FreeBSD.org</systemitem>domain contains a number of different hosts, including<systemitem class="fqdomainname">freefall.FreeBSD.org</systemitem>and<systemitem class="fqdomainname">bento.FreeBSD.org</systemitem>.</para><para>When adding an<acronym>IP</acronym>alias to an interface (using<command>ifconfig</command>)<emphasis>always</emphasis>use a netmask of<systemitem class="netmask">255.255.255.255</systemitem>(which can also be expressed as<systemitem class="netmask">0xffffffff</systemitem>).</para><para>The<acronym>MAC</acronym>address uniquely identifies every network card in existence. A typical<acronym>MAC</acronym>address looks like<systemitem class="etheraddress">08:00:20:87:ef:d0</systemitem>.</para><para>To carry out most system administration functions requires logging in as<systemitem class="username">root</systemitem>.</para>
Appearance:
The local machine can always be referred to by the name
localhost, which will have the IP
address
127.0.0.1.
The
FreeBSD.org
domain contains a number of different hosts, including
freefall.FreeBSD.org and
bento.FreeBSD.org.
When adding an IP alias to an
interface (using ifconfig)
always use a netmask of
255.255.255.255
(which can also be expressed as
0xffffffff).
The MAC address uniquely identifies
every network card in existence. A typical
MAC address looks like 08:00:20:87:ef:d0.
To carry out most system administration functions
requires logging in as
root.
Occasionally it is useful to show a
Uniform Resource Identifier (URI) without
making it an active hyperlink. The uri element
makes this possible:
uri ExampleUsage:
<para>This URL shows only as text:<uri>https://www.FreeBSD.org</uri>. It does not create a link.</para>
Appearance:
This URL shows only as text:
https://www.FreeBSD.org. It does not
create a link.
To create links, see Section 9.8, “Links”.
Email addresses are marked up as email
elements. In the HTML output format, the
wrapped text becomes a hyperlink to the email address. Other
output formats that support hyperlinks may also make the email
address into a link.
email with a Hyperlink ExampleUsage:
<para>An email address that does not actually exist, like<email>notreal@example.com</email>, can be used as an example.</para>
Appearance:
An email address that does not actually exist, like
<notreal@example.com>, can be used as an
example.
A FreeBSD-specific extension allows setting the
role attribute to nolink
to prevent the creation of the hyperlink to the email
address.
email Without a Hyperlink ExampleUsage:
<para>Sometimes a link to an email address like<email role="nolink">notreal@example.com</email>is not desired.</para>
Appearance:
Sometimes a link to an email address like
<notreal@example.com> is not
desired.
These elements are part of the FreeBSD extension to DocBook, and do not exist in the original DocBook DTD.
Two elements exist to describe parts of
Makefiles, buildtarget
and varname.
buildtarget identifies a build target
exported by a Makefile that can be
given as a parameter to make.
varname identifies a variable that can be
set (in the environment, on the command line with
make, or within the
Makefile) to influence the
process.
buildtarget and
varname ExampleUsage:
<para>Two common targets in a<filename>Makefile</filename>are<buildtarget>all</buildtarget>and<buildtarget>clean</buildtarget>.</para><para>Typically, invoking<buildtarget>all</buildtarget>will rebuild the application, and invoking<buildtarget>clean</buildtarget>will remove the temporary files (<filename>.o</filename>for example) created by the build process.</para><para><buildtarget>clean</buildtarget>may be controlled by a number of variables, including<varname>CLOBBER</varname>and<varname>RECURSE</varname>.</para>
Appearance:
Two common targets in a Makefile
are all and
clean.
Typically, invoking all will
rebuild the application, and invoking
clean will remove the temporary
files (.o for example) created by the
build process.
clean may be controlled by a
number of variables, including CLOBBER
and RECURSE.
Literal text, or text which should be entered verbatim, is often needed in documentation. This is text that is excerpted from another file, or which should be copied exactly as shown from the documentation into another file.
Some of the time, programlisting will
be sufficient to denote this text. But
programlisting is not always appropriate,
particularly when you want to include a portion of a file
“in-line” with the rest of the
paragraph.
On these occasions, use
literal.
literal ExampleUsage:
<para>The<literal>maxusers 10</literal>line in the kernel configuration file determines the size of many system tables, and is a rough guide to how many simultaneous logins the system will support.</para>
Appearance:
The maxusers 10 line in the kernel
configuration file determines the size of many system
tables, and is a rough guide to how many simultaneous
logins the system will support.
There will often be times when the user is shown what to do, or referred to a file or command line, but cannot simply copy the example provided. Instead, they must supply some information themselves.
replaceable is designed for this
eventuality. Use it inside other
elements to indicate parts of that element's content that
the user must replace.
replaceable ExampleUsage:
<screen>&prompt.user;<userinput>man<replaceable>command</replaceable></userinput></screen>
Appearance:
%mancommand
replaceable can be used in many
different elements, including literal.
This example also shows that replaceable
should only be wrapped around the content that the user
is meant to provide. The other content
should be left alone.
Usage:
<para>The<literal>maxusers<replaceable>n</replaceable></literal>line in the kernel configuration file determines the size of many system tables, and is a rough guide to how many simultaneous logins the system will support.</para><para>For a desktop workstation,<literal>32</literal>is a good value for<replaceable>n</replaceable>.</para>
Appearance:
The
maxusers
line in the kernel configuration file determines the size
of many system tables, and is a rough guide to how many
simultaneous logins the system will support.n
For a desktop workstation, 32 is a
good value for n.
Buttons presented by a graphical user interface are marked
with guibutton. To make the text look more
like a graphical button, brackets and non-breaking spaces are
added surrounding the text.
guibutton ExampleUsage:
<para>Edit the file, then click<guibutton>[ Save ]</guibutton>to save the changes.</para>
Appearance:
Edit the file, then click to save the changes.
All FreeBSD documents are available for download at https://download.freebsd.org/ftp/doc/
Questions that are not answered by the
documentation may be
sent to <freebsd-questions@FreeBSD.org>.
Send questions about this document to <freebsd-doc@FreeBSD.org>.