2. Conventions used in this document

2.1 About $LFS

Please read the following carefully: throughout this document you will frequently see the variable name $LFS. $LFS must at all times be replaced by the directory where the partition that contains the LFS system is mounted. How to create and where to mount the partition will be explained later on in full detail in chapter 4. In my case the LFS partition is mounted on /mnt/hda5. If I read this document myself and I see $LFS somewhere, I will pretend that I read /mnt/hda5. If I read that I have to run this command: cp inittab $LFS/etc I actually will run this: cp inittab /mnt/hda5/etc

It's important that you do this no matter where you read it; be it in commands you enter on the prompt, or in some file you edit or create.

If you want, you can set the environment variable LFS. This way you can literally enter $LFS in stead of replacing it by something like /mnt/hda5. This is accomplished by running: export LFS=/mnt/hda5

If I read cp inittab $LFS/etc, I literally can type cp inittab $LFS/etc and the shell will replace this command by cp inittab /mnt/hda5/etc automatically.

Do not forget to set the LFS variable at all times. If you haven't set the variable and you use it in a command, $LFS will be ignored and whatever is left will be executed. The command cp inittab $LFS/etc without the LFS variable set, will result in copying the inittab file to the /etc directory which will overwrite your system's inittab. A file like inittab isn't that big a problem as it can easily be restored, but if you would make this mistake during the installation of the C Library, you can break your system badly and might have to reinstall it if you don't know how to repair it. So that's why I strongly advise against using the LFS variable. You better replace $LFS yourself by something like /mnt/hda5. If you make a typo while entering /mnt/hda5, the worst thing that can happen is that you'll get an error saying "no such file or directory" but it won't break your system. Don't say I didn't warn you ;)

2.2 How to download the software

Throughout this document I will assume that you have stored all the packages you have downloaded in a subdirectory under $LFS/usr/src.

I myself have use the convention of having a $LFS/usr/src/sources directory. Under sources you'll find the directory 0-9 and the directories a through z. A package as sysvinit-2.78.tar.gz is stored under $LFS/usr/src/sources/s/ A package as bash-3.02.tar.gz is stored under $LFS/usr/src/sources/b/ and so forth. You don't have to follow this convention of course, I was just giving an example. It's better to keep the packages out of $LFS/usr/src and move them to a subdirectory, so we'll have a clean $LFS/usr/src directory in which we will unpack the packages and work with them.

The next chapter contains the list of all the packages you need to download, but the partition that is going to contain our LFS system isn't created yet. Therefore store the files temporarily somewhere where you want and remember to copy them to $LFS/usr/src/<somesubdirectory> when you have finished chapter 4.

2.3 How to install the software

Before you can actually start doing something with a package, you need to unpack it first. Often you will find the package files being tar'ed and gzip'ed (you can see this from a .tar.gz or .tgz extension). I'm not going to write down every time how to ungzip and how to untar an archive. I will tell you how to that once, in this paragraph. There is also the possibility that you have the possibility of downloading a .tar.bz2 file. Such a file is tar'ed and compressed with the bzip2 program. Bzip2 achieves a better compression than the commonly used gzip does. In order to use bz2 archives you need to have the bzip2 program installed. Most if not every distribution comes with this program so chances are high it is already installed on your system. If not, install it using your distribution's installation tool.

• Start by copying the package from wherever you have stored it to the $LFS/usr/src directory
• When you have a file that is tar'ed and gzip'ed, you unpack it by running: tar xvfz filename.tar.gz; rm filename.tar.gz or tar xvfz filename.tgz; rm filename.tgz
• When you have a file that is tar'ed and bzip'ed, you unpack it by running: tar --use-compress-prog=bzip2 -xvf filename.tar.bz2; rm filename.tar.bz2
• When you have a file that is only tar'ed, you unpack it by running tar xvf filename.tar; rm filename.tar

Note that immediately after we have unpacked the archive, we delete the package file as we don't need it anymore. That's why you have to copy the file and not move it. If you move it and then delete it, you will need to re-download it when you need it again.

When the archive is unpacked a new directory will be created under the current directory (and this document assumes that you unpack the archives under the $LFS/usr/src directory). You have to enter that new directory before you continue with the installation instructions. All the above will be summarized as 'Unpack the xxx archive'. So, when you read it, you copy the package to $LFS/usr/src, you run the tar program to ungzip/unbzip and untar it, then you enter the directory that was created and then you read the next line of the installation instructions.

After you have installed a package you can do two things with it. You can either delete the directory that contains the sources or you can keep it. If you decide to keep it, that's fine by me. But if you need the same package again in a later chapter (all software up to chapter 7.2 will be re-installed in chapter 7.3) you need to delete the directory first before using it again. If you don't do this, you might end up in trouble because old settings will be used (settings that apply to your normal Linux system but which don't apply anymore when you have restarted your computer into the LFS system). Doing a simple make clean does not always guarantee a totally clean source tree. The configure script also has files lying around in various subdirectories which are rarely removed by the make clean process.