glfs/introduction/important/position.xml

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<sect1 id="intro-important-position">
  <?dbhtml filename="position.html"?>

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  <title>The /usr Versus /usr/local Debate</title>

  <para><emphasis>Should I install XXX in <filename>/usr</filename> or
  <filename>/usr/local</filename>?</emphasis></para>

  <para>This is a question without an obvious answer for an
  LFS based system.</para>

  <para>In traditional Unix systems, <filename>/usr</filename> usually 
  contains files that come with the system distribution, and the <filename>
  /usr/local</filename> tree is free for the local administrator to manage. 
  The only really hard and fast rule is that Unix distributions should not 
  touch <filename>/usr/local</filename>, except perhaps to create the basic 
  directories within it.</para>

  <para>With Linux distributions, like Red Hat, Debian etc. a possible rule is
  that <filename>/usr</filename> is managed by the distribution's 
  package system and <filename>/usr/local</filename> is not.  This way the 
  package manager's database knows about every file within
  <filename>/usr</filename>.</para>

  <para>LFS users build their own system and so deciding where 
  the system ends and local files begin is not straightforward.  So the choice 
  should be made in order to make things easier to administer.  There are several
  reasons for dividing files between <filename>/usr</filename> and
  <filename>/usr/local</filename>.</para>

  <itemizedlist>
    <listitem>
      <para>On a network of several machines all running LFS, 
      or mixed LFS and other Linux distributions, 
      <filename>/usr/local</filename> could be used to hold packages
      that are common between all the computers in the network.  It can be
      NFS mounted or mirrored from a single server.  Here local 
      indicates local to the site.</para>
    </listitem>
    <listitem>
      <para>On a network of several computers all running an identical 
      LFS system <filename>/usr/local</filename> could hold 
      packages that are different between the machines.  In this case local refers 
      to the individual computers.</para>
    </listitem>
    <listitem>
      <para>Even on a single computer <filename>/usr/local</filename> can 
      be useful if you have several distributions installed simultaneously, and want 
      a place to put packages that will be the same on all of them.</para>
    </listitem>
    <listitem>
      <para>Or you might regularly rebuild your LFS, but 
      want a place to put files that you don't want to rebuild each time.  This way 
      you can wipe the LFS file system and start from a clean 
      partition every time without losing everything.</para>
    </listitem>
  </itemizedlist>

  <para>Some people ask why not use your own directory tree, e.g., <filename>
  /usr/site</filename>, rather than <filename>/usr/local</filename>?</para>

  <para>There is nothing stopping you, many sites do make their own trees, 
  however it makes installing new software more difficult.  Automatic installers
  often look for dependencies in <filename>/usr</filename> and
  <filename>/usr/local</filename>, and if the file it is looking
  for is in <filename>/usr/site</filename> instead, the installer will 
  probably fail unless you specifically tell it where to look.</para>

  <para><emphasis>What is the BLFS position on this?</emphasis></para>

  <para>All of the BLFS instructions install programs in
  <filename>/usr</filename> with optional instructions to install into
  <filename>/opt</filename> for some specific packages.</para>

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