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<!-- TITLE=Maximum RPM (RPM)//-->
<!-- AUTHOR=Edward Bailey//-->
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<!-- CHAPTER=13 //-->
<!-- PAGES=0163-0204 //-->
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<A NAME="PAGENUM-163"><P>Page 163</P></A>
<H3><A NAME="ch13_ 1">
Chapter 13
</A></H3>
<H2>
Inside the Spec File
</H2>
<A NAME="PAGENUM-164"><P>Page 164</P></A>
<P>In this chapter, we're going to cover the spec file in detail. There are a number of
different types of entries that comprise a spec file, and every one will be documented here. The
different types of entries are
</P>
<UL>
<LI> Comments—Human-readable notes ignored by RPM.
<LI> Tags—Data definitions.
<LI> Scripts—A set of commands to be executed at specific times.
<LI> Macros—A method of executing multiple commands easily.
<LI> The
%files list—A list of files to be included in the package.
<LI> Directives—Used in the
%files list to direct RPM to handle certain files in a
specific way.
<LI> Conditionals—Permit operating system_ or architecture-specific preprocessing of
the spec file.
</UL>
<P>Let's start by looking at comments.
</P>
<H3><A NAME="ch13_ 2">
13.1. Comments: Notes Ignored by RPM
</A></H3>
<P>Comments are a way to make RPM ignore a line in the spec file. The contents of a
comment line are entirely up to the person writing the spec file.
</P>
<P>To create a comment, enter an pound sign (#) at the start of the line. Any text following
the comment character will be ignored by RPM. Here's an example of a comment:
</P>
<!-- CODE SNIP //-->
<PRE>
# This is the spec file for playmidi 2.3...
</PRE>
<!-- END CODE SNIP //-->
<P>Comments can be placed in any section of the spec file.
</P>
<H3><A NAME="ch13_ 3">
13.2. Tags: Data Definitions
</A></H3>
<P>Looking at a spec file, the first thing you'll see are a number of lines, all following the
same basic format:
</P>
<!-- CODE SNIP //-->
<PRE>
<something>:<something-else>
</PRE>
<!-- END CODE SNIP //-->
<P><something> is known as a tag because it is used by RPM to name or tag some data. The tag
is separated from its associated data by a colon. The data is represented by
<something-else>. Tags are grouped together at the top of the spec file, in a section known as the
preamble. Here's an example of a tag and its data:
</P>
<!-- CODE SNIP //-->
<PRE>
Vendor: White Socks Software, Inc.
</PRE>
<!-- END CODE SNIP //-->
<P>In this example, the tag is Vendor. Tags are not case sensitive—they may be all
uppercase, all lowercase, or anything in between. The
Vendor tag is used to define the name of the
organization
</P>
<A NAME="PAGENUM-165"><P>Page 165</P></A>
<P>
producing the package. The data in this example is
White Socks Software, Inc.. Therefore, RPM will store
White Socks Software, Inc. as the vendor of the package.
</P>
<P>Note also that spacing between the tag, the colon, and the data is unimportant. Given
this, and the case insensitivity of the tag, each of the following lines is equivalent to the
previous example:
</P>
<!-- CODE //-->
<PRE>
VeNdOr : White Socks Software, Inc.
vendor:White Socks Software, Inc.
VENDOR : White Socks Software, Inc.
</PRE>
<!-- END CODE //-->
<P>The bottom line is that you can make tag lines as neat or as ugly as you like—RPM
won't mind either way. Note, however, that the tag's data might need to be formatted in a
particular fashion. If there are any such restrictions, we'll mention them. The following sections
group together tags of similar functions for easier reference, starting with the tags used to create
the package name.
</P>
<H4><A NAME="ch13_ 4">
13.2.1. Package Naming Tags
</A></H4>
<P>The following tags are used by RPM to produce the package's final name. Since the name
is always in this format:
</P>
<!-- CODE SNIP //-->
<PRE>
<name>-<version>-<release>
</PRE>
<!-- END CODE SNIP //-->
<P>it's only natural that the three tags are known as
name, version, and release.
</P>
<B>
13.2.1.1. The name Tag
</B>
<P>The name tag is used to define the name of the software being packaged. In most (if not
all) cases, the name used for a package should be identical in spelling and case to the software
being packaged. The name cannot contain any whitespace: If it does, RPM will only use the first
part of the name (up to the first space). Therefore, if the name of the software being packaged
is cdplayer, the name tag should be something like this:
</P>
<!-- CODE SNIP //-->
<PRE>
Name: cdplayer
</PRE>
<!-- END CODE SNIP //-->
<B>
13.2.1.2. The version Tag
</B>
<P>The version tag defines the version of the software being packaged. The version specified
should be as close as possible to the format of the original software's version. In most cases, there
should be no problem specifying the version just as the software's original developer did.
However, there is a restriction: There can be no dashes in the version. If you forget, RPM will
remind you:
</P>
<!-- CODE SNIP //-->
<PRE>
# rpm -ba cdplayer-1.0.spec
Package: cdplayer
Illegal `-' char in version: 1.0-a
#
</PRE>
<!-- END CODE SNIP //-->
<A NAME="PAGENUM-166"><P>Page 166</P></A>
<P>Spaces in the version will also cause problems, in that anything after the first space will be
ignored by RPM. The bottom line is that you should stick with alphanumeric characters
and periods, and you'll never have to worry about it. Here's a sample
version tag:
</P>
<!-- CODE SNIP //-->
<PRE>
Version: 1.2
</PRE>
<!-- END CODE SNIP //-->
<B>
13.2.1.3. The release Tag
</B>
<P>The release tag can be thought of as the package's version. The release is traditionally an
integer—for example, when a specific piece of software at a particular version is first
packaged, the release should be 1. If it is necessary to repackage that software at the same version,
the release should be incremented. When a new version of the software becomes available, the
release should drop back to 1 when it is first packaged.
</P>
<P>Note that we used the word traditionally. The only hard-and-fast restriction to the release
format is that there can be no dashes in it. Be aware that if you buck tradition, your users may
not understand what your release means.
</P>
<P>It is up to the package builder to determine which build represents a new release and to
update the release manually. Here is what a typical
release tag might look like:
</P>
<!-- CODE SNIP //-->
<PRE>
Release: 5
</PRE>
<!-- END CODE SNIP //-->
<H4>
13.2.2. Descriptive Tags
</H4>
<P>Descriptive tags provide information primarily for people who want to know a bit more
about the package and who produced it. They are part of the package file, and most of them can
be seen by issuing an rpm -qi command.
</P>
<B>
13.2.2.1. The %description Tag
</B>
<P>The %description tag is used to provide an in-depth description
of the packaged software. The description should be several sentences describing, to an uninformed user, what the
software does.
</P>
<P>The %description tag is a bit different from the other tags in the preamble. For one, it
starts with a percent sign. The other difference is that the data specified by the
%description tag can span more than one line. In addition, a primitive formatting capability exists. If a line
starts with a space, that line will be displayed verbatim by RPM. Lines that do not start with a
space are assumed to be part of a paragraph and will be formatted by RPM. It's even possible to
mix and match formatted and unformatted lines. Here are some examples:
</P>
<!-- CODE //-->
<PRE>
%description
It slices! It dices! It's a CD player app that can't be beat. By using the
resonant frequency of the CD itself, it is able to simulate 20X
oversampling. This leads to sound quality that cannot be equaled with more
mundane software...
</PRE>
<!-- END CODE //-->
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