The largest part of a specfile is the shell script that builds the package. LPMtool does not build an application directly. The specfile provides a shell script that does that.

The process of building an application, from source code, varies with each application, but it usually consists of the following, general steps:

Try to follow this general outline when creating a new specfile for an application. A “%begin” line should mark the beginning of the shell script that corresponds to each part of the build process. Each shell script should have a short name, which is given after the “%begin”. A “%begin” without a name gets a name called “setup”, this is usually the very first shell script in a specfile. By convention, the other shell scripts should be called “build” and “install” (as offered in the sample specfile from the beginning of Chapter 7, Building packages), but the names are purely arbitrary.

lpbuild automatically creates several work directories, when processing the specfile. The first work directory is allocated for the unpacked source code, and a second work directory is allocated for the installation image. The actual location of the work directory is not very important. LPMtool takes care of creating this directory, and removing it after the application package files are built.

By default, lpbuild runs each “%begin” script from specfile, one after another.

By default, lpbuild creates the work directories before executing the first “%begin” script. After the last “%begin” script completes successfully, the package files are created, and the work directories are automatically deleted. lpbuild has an option that runs a single “%begin” script only, without deleting the temporary work directories. This provides for incremental development and debugging of a new specfile.