lfs-book-zh_CN/chapter02/install.xml

<sect1 id="ch02-install">
<title>How to install the software</title>

<para>Before you start using the LFS book, we should point out that all
of the commands here assume that you are using the bash shell.  If you
aren't, the commands may work but we can't guarantee it.  If you want a
simple life, use bash.</para>

<para>Before you can actually start doing something with a package, you need
to unpack it first. Often the package files are tar'ed and
gzip'ed or bzip2'ed. I'm not going to write down every time how to
unpack an archive. I will explain how to do that once, in this 
section.</para>

<para>To start with, change to the $LFS/usr/src directory by running:</para>

<para><screen><userinput>cd $LFS/usr/src</userinput></screen></para>

<para>If a file is tar'ed and gzip'ed, it is unpacked by
running either one of the following two commands, depending on the
filename:</para>

<para><screen><userinput>tar xvzf filename.tar.gz</userinput>
<userinput>tar xvzf filename.tgz</userinput></screen></para>


<para>If a file is tar'ed and bzip2'ed, it is unpacked by
running:</para>

<para><screen><userinput>bzcat filename.tar.bz2 | tar xv</userinput></screen></para>

<para>Some tar programs (most of them nowadays but not all of them) are
slightly modified to be able to use bzip2 files directly using either
the I, the y or the j tar parameter, which works the same as the z tar 
parameter to handle gzip archives. The above construction works no matter how
your host system decided to patch bzip2.</para>

<para>If a file is just tar'ed, it is unpacked by running:</para>

<para><screen><userinput>tar xvf filename.tar</userinput></screen></para>

<para>When an archive is unpacked, a new directory will be created under the
current directory (and this book assumes that the archives are unpacked
under the $LFS/usr/src directory). Please enter that new directory
before continuing with the installation instructions. Again, every time
this book is going to install a package, it's up to you to unpack the source
archive and cd into the newly created directory.</para>

<para>From time to time you will be dealing with single files such as patch
files. These files are generally gzip'ed or bzip2'ed. Before such files
can be used they need to be uncompressed first.</para>

<para>If a file is gzip'ed, it is unpacked by running:</para>

<para><screen><userinput>gunzip filename.gz</userinput></screen></para>

<para>If a file is bzip2'ed, it is unpacked by running:</para>

<para><screen><userinput>bunzip2 filename.bz2</userinput></screen></para>

<para>After a package has been installed, two things can be done with it:
either the directory that contains the sources can be deleted,
or it can be kept. If it is kept, that's fine with me, but if the 
same package is needed again in a later chapter, the directory 
needs to be deleted first before using it again. If this is not done, 
you might end up in trouble because old settings will be used (settings 
that apply to the host system but which don't always apply to 
the LFS system). Doing a simple make clean or make distclean does not 
always guarantee a totally clean source tree.</para>

<para>So, save yourself a lot of hassle and just remove the source directory
immediately after you have installed it.</para>

<para>There is one exception; the kernel source tree. Keep it around as you
will need it later in this book when building a kernel. Nothing will use
the kernel tree so it won't be in your way.</para>

</sect1>