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<?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;
]>
<sect1 id="ch-scripts-locale">
<?dbhtml filename="locale.html"?>
<title>Configuring the System Locale</title>
<indexterm zone="ch-scripts-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>). <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>Charmaps can have a number of aliases, 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 (e.g., require
that <quote>UTF-8</quote> is written as <quote>UTF-8</quote>, not
<quote>utf8</quote>), so it is safest in most
cases 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 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 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>
<!-- FIXME: the xlib example will became obsolete real soon -->
<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 if the locale does not exactly match one of the character
map names in its internal files:</para>
<screen><computeroutput>Warning: locale not supported by Xlib, locale set to C</computeroutput></screen>
<para>In several cases Xlib expects that the character map will be listed in
uppercase notation with canonical dashes. For instance, "ISO-8859-1" rather
than "iso88591". It is also possible to find an appropriate specification by
removing the charmap part of the locale specification. This can be checked
by running the <command>locale charmap</command> command in both locales.
For example, one would have to change "de_DE.ISO-8859-15@euro" to
"de_DE@euro" 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 > /etc/locale.conf << "EOF"
<literal>LANG=<replaceable><ll>_<CC>.<charmap><@modifiers></replaceable></literal>
EOF</userinput></screen>
<para>Note that you can modify <filename>/etc/locale.conf</filename> with
Systemd <command>localectl</command> utility. To use <command>localectl</command>
for the example above, run:</para>
<screen><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
seperate 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><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>The <quote>C</quote> (default) and <quote>en_US</quote> (the recommended
one for United States English users) locales are different. <quote>C</quote>
uses the US-ASCII 7-bit character set, and treats bytes with the high bit set
as invalid characters. That's why, e.g., the <command>ls</command> command
substitutes them with question marks in that locale. Also, an attempt to send
mail with such characters from Mutt or Pine results in non-RFC-conforming
messages being sent (the charset in the outgoing mail is indicated as <quote>unknown
8-bit</quote>). So you can use the <quote>C</quote> locale only if you are sure that
you will never need 8-bit characters.</para>
<para>UTF-8 based locales are not supported well by many programs.
Work is in progress to document and, if possible, fix such problems, see
<ulink url="&blfs-root;view/svn/introduction/locale-issues.html"/>.</para>
</sect1>
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