glfs/general/sysutils/which.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

<!--  <!ENTITY which-download-http "http://www.xs4all.nl/~carlo17/which/which-&which-version;.tar.gz">-->

  <!ENTITY which-download-http "&gnu-http;/which/which-&which-version;.tar.gz">
  <!ENTITY which-download-ftp  " ">
  <!ENTITY which-md5sum        "097ff1a324ae02e0a3b0369f07a7544a">
  <!ENTITY which-size          "148 KB">
  <!ENTITY which-buildsize     "1 MB">
  <!ENTITY which-time          "less than 0.1 SBU">
]>

<sect1 id="which" xreflabel="Which-&which-version;">
  <?dbhtml filename="which.html"?>


  <title>Which-&which-version; and Alternatives</title>

  <para>
    The presence or absence of the <command>which</command> program in the
    main LFS book is probably one of the most contentious issues on the
    mailing lists. It has resulted in at least one flame war in the past. To
    hopefully put an end to this once and for all, presented here are two
    options for equipping your system with <command>which</command>. The
    question of which <quote><command>which</command></quote> is for you to
    decide.
  </para>

  <indexterm zone="which">
    <primary sortas="a-Which">Which</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to GNU Which</title>

    <para>
      The first option is to install the actual GNU
      <application>which</application> package.
    </para>

    &lfs120_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&which-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&which-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &which-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &which-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &which-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &which-time;
        </para>
      </listitem>
    </itemizedlist>

  </sect2>

  <sect2 role="installation">
    <title>Installation of Which</title>

    <para>
      Install <application>which</application> by running the following
      commands:
    </para>

<screen><userinput>./configure --prefix=/usr &amp;&amp;
make</userinput></screen>

    <para>
      This package does not come with a test suite.
    </para>

    <para>
      Now, as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>make install</userinput></screen>

  </sect2>

  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Program</segtitle>
      <segtitle>Installed Libraries</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>which</seg>
        <seg>None</seg>
        <seg>None</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="which-prog">
        <term><command>which</command></term>
        <listitem>
          <para>
            shows the full path of (shell) commands installed in your
            <envar>PATH</envar>
          </para>
          <indexterm zone="which which-prog">
            <primary sortas="b-which">which</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

  <sect2 role="installation">
    <title>The 'which' Script</title>

    <para>
      The second option (for those who don't want to install the package)
      is to create a simple script (execute as the
      <systemitem class="username">root</systemitem> user):
    </para>

<screen role="root"><userinput>cat &gt; /usr/bin/which &lt;&lt; "EOF"
<literal>#!/bin/bash
type -pa "$@" | head -n 1 ; exit ${PIPESTATUS[0]}</literal>
EOF
chmod -v 755 /usr/bin/which
chown -v root:root /usr/bin/which</userinput></screen>

    <para>
      This should work OK and is probably the easiest solution
      for most cases, but is not the most comprehensive implementation.
    </para>

  </sect2>

</sect1>