This section provides an overview of some of the parts of an RPM package. Much of the information is of primary use to developers, but because some of the terms are referenced in the RPM command descriptions, they are explained briefly here.
An RPM package has three primary components. The header contains all the information about the package, such as its name and version, a description, a list of included files, the copyright terms, and where the source file can be found. The signature contains information used to verify the integrity and authenticity of the package. The archive contains the actual files that make up the package.
When a package is being built, one of the requirements for its developers is to create a spec file. If you download the source rpm for a package, you can look at the spec file; it has a filename of package.spec (e.g., yum.spec for the yum spec file). The spec file contains all the information required to build a package, including a description of the software, instructions telling the rpmbuild command how to build the package, and a list of the files included and where they get installed. Some other features of spec files include the following:
Macros are sequences of commands stored together and executed by invoking the macro name. The RPM build process provides two standard macros: %setup to unpack the original sources and %patch to apply patches. Other macros appear later in this chapter in the command descriptions and are described ...