%general-entities; ]> In this chapter, we enter the building site and start constructing the CLFS system in earnest. The installation of this software is straightforward. Although in many cases the installation instructions could be made shorter and more generic, we have opted to provide the full instructions for every package to minimize the possibilities for mistakes. The key to learning what makes a Linux system work is to know what each package is used for and why the user (or the system) needs it. For every installed package, a summary of its contents is given, followed by concise descriptions of each program and library the package installed. The order that packages are installed in this chapter needs to be strictly followed to ensure that no program accidentally acquires a path referring to ${CLFS}/cross-tools hard-wired into it. For the same reason, do not compile packages in parallel. Compiling in parallel may save time (especially on dual-CPU machines), but it could result in a program containing a hard-wired path to ${CLFS}/cross-tools, which will cause the program to stop working when that directory is removed. To keep track of which package installs particular files, a package manager can be used. For a general overview of different styles of package managers, please take a look at the next page.