lfs-book-zh_CN/stylesheets/lfs-xsl/docbook-xsl-1.78.1/params/man.th.title.max.length.xml

<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
          xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
          version="5.0" xml:id="man.th.title.max.length">
<refmeta>
<refentrytitle>man.th.title.max.length</refentrytitle>
<refmiscinfo class="other" otherclass="datatype">integer</refmiscinfo>
</refmeta>
<refnamediv>
<refname>man.th.title.max.length</refname>
<refpurpose>Maximum length of title in header/footer</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment xml:id="man.th.title.max.length.frag">
<xsl:param name="man.th.title.max.length">20</xsl:param>
</src:fragment>
</refsynopsisdiv>

<refsection><info><title>Description</title></info>

<para>Specifies the maximum permitted length of the title part of the
man-page <literal>.TH</literal> title line header/footer. If the title
exceeds the maxiumum specified, it is truncated down to the maximum
permitted length.</para>

<refsection><info><title>Details</title></info>
  

<para>Every man page generated using the DocBook stylesheets has a
title line, specified using the <literal>TH</literal> roff
macro. Within that title line, there is always, at a minimum, a title,
followed by a section value (representing a man "section" -- usually
just a number).</para>

<para>The title and section are displayed, together, in the visible
header of each page. Where in the header they are displayed depends on
OS the man page is viewed on, and on what version of nroff/groff/man
is used for viewing the page. But, at a minimum and across all
systems, the title and section are displayed on the right-hand column
of the header. On many systems -- those with a modern groff, including
Linux systems -- they are displayed twice: both in the left and right
columns of the header.</para>

<para>So if the length of the title exceeds a certain percentage of
the column width in which the page is viewed, the left and right
titles can end up overlapping, making them unreadable, or breaking to
another line, which doesn't look particularly good.</para>

<para>So the stylesheets provide the
<parameter>man.th.title.max.length</parameter> parameter as a means
for truncating titles that exceed the maximum length that can be
viewing properly in a page header.</para>

<para>The default value is reasonable but somewhat arbitrary. If you
have pages with long titles, you may want to experiment with changing
the value in order to achieve the correct aesthetic results.</para>
</refsection>

</refsection>
</refentry>