lfs-book-zh_CN/chapter03/introduction.xml

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<sect1 id="materials-introduction">
  <?dbhtml filename="introduction.html"?>

  <title>Introduction</title>

  <para>This chapter includes a list of packages that need to be downloaded in
  order to build a basic Linux system. The listed version numbers correspond to
  versions of the software that are known to work, and this book is based on
  their use. We highly recommend against using newer versions because the build
  commands for one version may not work with a newer version. The newest package
  versions may also have problems that require work-arounds. These work-arounds
  will be developed and stabilized in the development version of the
  book.</para>

  <para>Download locations may not always be accessible. If a download
  location has changed since this book was published, Google (<ulink
  url="http://www.google.com/"/>) provides a useful search engine for
  most packages. If this search is unsuccessful, try one of the
  alternative means of downloading discussed at <ulink
  url="&lfs-root;lfs/packages.html#packages"/>. </para>

  <para>Downloaded packages and patches will need to be stored somewhere
  that is conveniently available throughout the entire build. A working
  directory is also required to unpack the sources and build them.
  <filename class="directory">$LFS/sources</filename> can be used both
  as the place to store the tarballs and patches and as a working
  directory. By using this directory, the required elements will be
  located on the LFS partition and will be available during all stages
  of the building process.</para>

  <para>To create this directory, execute the following command, as user
  <systemitem class="username">root</systemitem>, before starting the download
  session:</para>

<screen role="nodump"><userinput>mkdir -v $LFS/sources</userinput></screen>

  <para>Make this directory writable and sticky. <quote>Sticky</quote>
  means that even if multiple users have write permission on a
  directory, only the owner of a file can delete the file within a
  sticky directory. The following command will enable the write and
  sticky modes:</para>

<screen role="nodump"><userinput>chmod -v a+wt $LFS/sources</userinput></screen>

  <para>An easy way to download all of the packages and patches is by using
  <ulink url="../wget-list">wget-list</ulink> as an input to
  <command>wget</command>. For example:</para>

<screen role="nodump"><userinput>wget -i wget-list -P $LFS/sources</userinput></screen> 

  <para>Additionally, starting with LFS-7.0, there is a separate file, 
  <ulink url="../md5sums">md5sums</ulink>, can be used to verify that all
  the correct packages are available before proceeding.  Place that file in 
  <filename class="directory">$LFS/sources</filename> and run:</para>

<screen role="nodump"><userinput>pushd  $LFS/sources
md5sum -c md5sums
popd</userinput></screen> 

</sect1>