source: chapter07/profile.xml@ c45b780

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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>ISO-8859-1</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><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>

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

<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>

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

<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>