source: general/sysutils/which.xml@ 539ace5

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
   "http://www.oasis-open.org/docbook/xml/4.4/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-ftp  "ftp://ftp.gnu.org/gnu/which/which-&which-version;.tar.gz">
  <!ENTITY which-md5sum        "830b83af48347a9a3520f561e47cbc9b">
  <!ENTITY which-size          "123 KB">
  <!ENTITY which-buildsize     "940 KB">
  <!ENTITY which-time          "0.03 SBU">
]>

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

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

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

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

  <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>

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

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

    <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 program)
    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>