source: BOOK/system-config/common/locale.xml@ a16caa0

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  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<sect1 id="ch-config-locale">
  <title>Setting Up Locale Information</title>
  <?dbhtml filename="locale.html"?>

  <indexterm zone="ch-config-locale">
    <primary sortas="e-/etc/locale.conf">/etc/locale.conf</primary>
  </indexterm>

  <para>The <filename>/etc/locale.conf</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>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> or <quote>US</quote>).
  <replaceable>[charmap]</replaceable> should be replaced with the
  canonical charmap for your chosen locale. Optional modifiers such as
  <quote>@euro</quote> may also be present.</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_US.utf8</quote> in our example).</para>

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

  <para>For the <quote>en_US.utf8</quote> locale, the above command
  will print:</para>

<screen><computeroutput>UTF-8</computeroutput></screen>

  <para>This results in a final locale setting of <quote>en_US.UTF-8</quote>.
  It is important that the locale found using the heuristic above is tested
  prior to it being added to <filename>/etc/locale.conf</filename>:</para>

<screen role="nodump"><userinput>LC_ALL=[locale name] locale territory
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 language name, 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 10 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 CLFS 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/locale.conf</filename> file:</para>

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

LANG=<replaceable>[ll]</replaceable>_<replaceable>[CC]</replaceable>.<replaceable>[charmap]</replaceable><replaceable>[@modifiers]</replaceable>

# End /etc/locale.conf</literal>
EOF</userinput></screen>

  <para>Note that you can modify <filename>/etc/locale.conf</filename> with
  systemd's <command>localectl</command> utility. To use
  <command>localectl</command> for the example above, run:</para>

<screen role="nodump"><userinput>localectl set-locale LANG="<replaceable>[ll]_[CC][charmap][@modifiers]</replaceable>"</userinput></screen>

  <para>You can also specify other language specific environment variables such
  as <envar>LANG</envar>, <envar>LC_CTYPE</envar>, <envar>LC_NUMERIC</envar> or
  any other environment variable from <command>locale</command> output. Just
  separate them with a space. An example where <envar>LANG</envar> is set as
  en_US.UTF-8 but <envar>LC_CTYPE</envar> is set as just en_US is:</para>

<screen role="nodump"><userinput>localectl set-locale LANG="en_US.UTF-8" LC_CTYPE="en_US"</userinput></screen>

  <note><para>Please note that <command>localectl</command> command can
  be used  only on a system booted with systemd.</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. UTF-8 has been tested on the English, French, German,
  Italian, and Spanish locales. All other locales are untested. If you discover
  issues with any other locale please open a ticket in our Trac system.</para>

  <para>Some locales need additional programs and support. CLFS will not be
  supporting these locales in the book. We welcome the support for these other
  locales via <ulink url="&cblfs-root;"/>.</para>

</sect1>