source: BOOK/bootscripts/common/profile.xml@ 966d3087

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<sect1 id="ch-scripts-profile">
  <title>The Bash Shell Startup Files</title>
  <?dbhtml filename="profile.html"?>

  <indexterm zone="ch-scripts-profile">
    <primary sortas="e-/etc/profile">/etc/profile</primary>
  </indexterm>

  <para>The shell program <command>/bin/bash</command> (hereafter
  referred to as <quote>the shell</quote>) uses a collection of startup
  files to help create an environment to run in. Each file has a
  specific use and may affect login and interactive environments
  differently. The files in the <filename
  class="directory">/etc</filename> directory provide global settings.
  If an equivalent file exists in the home directory, it may override
  the global settings.</para>

  <para>An interactive login shell is started after a successful login,
  using <command>/bin/login</command>, by reading the
  <filename>/etc/passwd</filename> file. An interactive non-login shell
  is started at the command-line (e.g.,
  <prompt>[prompt]$</prompt><command>/bin/bash</command>). A
  non-interactive shell is usually present when a shell script is
  running. It is non-interactive because it is processing a script and
  not waiting for user input between commands.</para>

  <para>For more information, see <command>info bash</command> under the
  <emphasis>Bash Startup Files and Interactive Shells</emphasis> section.</para>

  <para>The files <filename>/etc/profile</filename> and
  <filename>~/.bash_profile</filename> are read when the shell is
  invoked as an interactive login shell.</para>

  <para>The base <filename>/etc/profile</filename> below sets some
  environment variables necessary for native language support. Setting
  them properly results in:</para>

  <itemizedlist>
    <listitem>
      <para>The output of programs translated into the native language</para>
    </listitem>
    <listitem>
      <para>Correct classification of characters into letters, digits and
      other classes. This is necessary for <command>bash</command> to
      properly accept non-ASCII characters in command lines in non-English
      locales</para>
    </listitem>
    <listitem>
      <para>The correct alphabetical sorting order for the country</para>
    </listitem>
    <listitem>
      <para>Appropriate default paper size</para>
    </listitem>
    <listitem>
      <para>Correct formatting of monetary, time, and date values</para>
    </listitem>
  </itemizedlist>

  <para>This script also sets the <envar>INPUTRC</envar> environment variable
  that makes Bash and Readline use the <filename>/etc/inputrc</filename> file
  created earlier.</para>

  <para>Replace <replaceable>[ll]</replaceable> below with the
  two-letter code for the desired language (e.g., <quote>en</quote>) and
  <replaceable>[CC]</replaceable> with the two-letter code for the
  appropriate country (e.g., <quote>GB</quote>).
  <replaceable>[charmap]</replaceable> should be replaced with the
  canonical charmap for your chosen locale.</para>

  <para>The list of all locales supported by Glibc can be obtained by running
  the following command:</para>

<screen role="nodump"><userinput>locale -a</userinput></screen>

  <para>Locales can have a number of synonyms, e.g. <quote>ISO-8859-1</quote>
  is also referred to as <quote>iso8859-1</quote> and <quote>iso88591</quote>.
  Some applications cannot handle the various synonyms correctly, so it is
  safest to choose the canonical name for a particular locale. To determine
  the canonical name, run the following command, where <replaceable>[locale
  name]</replaceable> is the output given by <command>locale -a</command> for
  your preferred locale (<quote>en_GB.iso88591</quote> in our example).</para>

<screen role="nodump"><userinput>LC_ALL=<replaceable>[locale name]</replaceable> locale charmap</userinput></screen>

  <para>For the <quote>en_GB.iso88591</quote> locale, the above command
  will print:</para>

<screen><computeroutput>ISO-8859-1</computeroutput></screen>

  <para>This results in a final locale setting of <quote>en_GB.ISO-8859-1</quote>.
  It is important that the locale found using the heuristic above is tested prior
  to it being added to the Bash startup files:</para>

<screen role="nodump"><userinput>LC_ALL=[locale name] locale country
LC_ALL=[locale name] locale language
LC_ALL=[locale name] locale charmap
LC_ALL=[locale name] locale int_curr_symbol
LC_ALL=[locale name] locale int_prefix</userinput></screen>

  <para>The above commands should print the country and language names, the
  character encoding used by the locale, the local currency and the prefix
  to dial before the telephone number in order to get into the country. If
  any of the commands above fail with a message similar to the one shown
  below, this means that your locale was either not installed in Chapter 6
  or is not supported by the default installation of Glibc.</para>

<screen><computeroutput>locale: Cannot set LC_* to default locale: No such file or directory</computeroutput></screen>

  <para>If this happens, you should either install the desired locale using
  the <command>localedef</command> command, or consider choosing a different
  locale. Further instructions assume that there are no such error messages
  from Glibc.</para>

  <para>Some packages beyond LFS may also lack support for your chosen locale.
  One example is the X library (part of the X Window System), which outputs
  the following error message:</para>

<screen><computeroutput>Warning: locale not supported by Xlib, locale set to C</computeroutput></screen>

  <para>Sometimes it is possible to fix this by removing the charmap part of
  the locale specification, as long as that does not change the character map
  that Glibc associates with the locale (this can be checked by running the
  <command>locale charmap</command> command in both locales). For example,
  one would have to change &quot;de_DE.ISO-8859-15@euro&quot; to
  &quot;de_DE@euro&quot; in order to get this locale recognized by Xlib.</para>

  <para>Other packages can also function incorrectly (but may not necessarily
  display any error messages) if the locale name does not meet their expectations.
  In those cases, investigating how other Linux distributions support your locale
  might provide some useful information.</para>

  <para>Once the proper locale settings have been determined, create the
  <filename>/etc/profile</filename> file:</para>

<screen><userinput>cat &gt; /etc/profile &lt;&lt; "EOF"
<literal># Begin /etc/profile

export LANG=<replaceable>[ll]</replaceable>_<replaceable>[CC]</replaceable>.<replaceable>[charmap]</replaceable>
export INPUTRC=/etc/inputrc

# End /etc/profile</literal>
EOF</userinput></screen>

  <note>
    <para>The <quote>C</quote> (default) and <quote>en_US</quote>
    (the recommended one for United States English users) locales are
    different.</para>
  </note>

  <para>Setting the keyboard layout, screen font, and locale-related
  environment variables are the only internationalization steps needed to
  support locales that use ordinary single-byte encodings and left-to-right
  writing direction. More complex cases (including UTF-8 based locales)
  require additional steps and additional patches because many applications
  tend to not work properly under such conditions. These steps and patches
  are not included in the LFS book and such locales are not yet supported
  by LFS.</para>

</sect1>