Objective 2: Packaging Software

Many package formats are used on Linux. The two main ones are Debian's deb format and Red Hat's RPM format. Debian has a package called alien that is able to assimilate and transform foreign package formats, specifically RPM, so they can be installed. The alien tool can be used to exchange .rpm, .tgz, and .deb package formats.

The general methodology when building a package is to set down a build process for the source that is as close as possible to what someone would do by hand, but then to pack the files into their own directory hierarchy that contains only the files that belong in the package. The contents of the hierarchy are then packaged. A lot of the magical things happen in the build process to put files into this dummy hierarchy in such a way that they will still work when the user installs them in the / and /usr directory hierachies.

Building RPM Packages

Building RPM packages from an SRPM (source RPM) package is pretty straightforward. First, of course, you must find and download the source package. These are typically stored in src.rpm files.

There are two ways of building an RPM source package. If the package is satisfactory to you and you only want to recompile it for your system (for example, because you use SUSE while the binary package was built for Red Hat), you can simply enter:

rpmbuild --rebuild package.src.rpm

This builds a binary package from the source package and places the result in the RPMS directory discussed later.

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