In order to keep time properly, /etc/localtime must contain the correct time zone data. Look around in /usr/share/zoneinfo/ and pick your timezone or a near-by big city. Please avoid the /usr/share/zoneinfo/Etc/GMT* timezones as their names do not indicate the expected zones. For instance, GMT-8 is in fact GMT+8.

# cp /usr/share/zoneinfo/Europe/Berlin /etc/localtime
# date
Sun Feb 16 08:26:44 CET 2003

In most Gentoo Linux installations, your hardware clock is set to UTC (or GMT, Greenwich Mean Time) and then your timezone is taken into account to determine the actual, local time. If, for some reason, you need your hardware clock not to be in UTC, you will need to edit /etc/conf.d/clock and change the value of CLOCK from UTC to local.

(recommended:)
CLOCK="UTC"
(or:)
CLOCK="local"

A Locale is a set of information that most programs use for determining country and language specific settings. The locales and their data are part of the system library and can be found at /usr/share/locale on most systems. A locale name is generally named ab_CD where ab is your two (or three) letter language code (as specified in ISO-639) and CD is your two letter country code (as specified in ISO-3166).

Locale settings are stored in environment variables. These are typically set in the /etc/env.d/02locale (for system-wide settings) and ~/.bashrc (for user-specific settings) file. The variables controlling different aspects of locale settings are given in the table below, those with highest precedence (ie. those that override settings below them) are at the top of the table. All variables take one name of a locale in ab_CD format given above.

Most typically users only set the LANG variable and perhaps LC_CTYPE variable on user level by adding definitions to shells startup files defining the environment variable manually from command line:

export LANG="de_DE@euro"

It is also possible to set a system-wide locale for all users and programs:

LC_ALL="de_DE@euro"
LANG="de_DE@euro"

A common practice is to use only per user locale settings and leave the default system locale unset. In this case system locale defaults to a special value "C", which for historical reasons maps to the English locale.

For message based localization to work in programs that support it, you will probably need to have programs compiled with the nls (Native language support) USE flag set. Most of the programs using nls also need the gettext library to extract and use localized messages. Of course, Portage will automatically install it when needed.

Once you have set the right locale, be sure to update your environment variables to make your system aware of the change:

(For system-wide default locale:)
# env-update && source /etc/profile

(For user-specific locale:)
$ source ~/.bashrc

After this, you will need to kill your X server by pressing Ctrl-Alt-Backspace, log out, then log in as user.

Now, verify that the changes have taken effect:

$ env | grep -i LC_

There is also additional localisation variable called LINGUAS, which affects to localisation files that get installed in gettext-based programs, and decides used localisation for some specific software packages, such as kde-base/kde-i18n and app-office/openoffice. The variable takes in space-separated list of language codes, and suggested place to set it is /etc/make.conf:

# nano -w /etc/make.conf
(Add in the LINGUAS variable. For instance, 
for German, Finnish and English:)
LINGUAS="de fi en"

If you use a locale that isn't available by default, you should use localedef to generate your locale. For instance:

# localedef -c -i en_US -f ISO-8859-15 en_US.ISO-8859-15

After having generated the locale, you can export the LANG variable as you see fit.

# export LANG="en_US.ISO-8859-15"

Be sure to update the environment after the change:

# env-update && source /etc/profile

After this, you will need to kill your X server by pressing Ctrl-Alt-Backspace, log out, then log in as user.

You will probably only use one or maybe two locales on your system. Up until now after compiling glibc a full set of all available locales has been created. As of now you can activate the userlocales USE flag and specify only the locales you will need in /etc/locales.build.

echo "sys-libs/glibc userlocales" >> /etc/portage/package.use

Now specify the locales you want to be able to use:

en_US/ISO-8859-1
en_US.UTF-8/UTF-8
de_DE/ISO-8859-1
de_DE@euro/ISO-8859-15

The next step is to re-compile glibc. Of course you can defer this until the next glibc upgrade is available.

The keyboard layout used by the console is set in /etc/conf.d/keymaps by the KEYMAP variable. Valid values can be found in /usr/share/keymaps/{arch}/. i386 has further subdivisions into layout (qwerty/, azerty/, etc.). Some languages have multiple options, so you may wish to experiment to decide which one fits your needs best.

KEYMAP="de"
KEYMAP="de-latin1"
KEYMAP="de-latin1-nodeadkeys"

The keyboard layout to be used by the X server is specified in /etc/X11/xorg.conf by the XkbLayout option.

 Section "InputDevice"
     Identifier  "Keyboard1"
     ...
     Option "XkbLayout"    "de"
     #Option "XkbModel"     "pc105"    ## this is for international keyboards.
     # Option "XkbVariant"  "nodeadkeys" ## this would be used for xterm input
     ...

If you have an international keyboard layout, you should set the option XkbModel to pc102 or pc105, as this will allow mapping of the additional keys specific to your keyboard.

Deadkeys allow you to press keys that will not show immediately but will be combined with another letter to produce a single character such as é,è,á,à, etc. Setting XkbVariant to nodeadkeys allows input these special characters into X terminals.

If you would like to switch between more than one keyboard layout (for example English and Russian), all you have to do is add a few lines to xorg.conf that specify the desired layouts and the shortcut command.

 Section "InputDevice"
     Identifier  "Keyboard1"
     ...
     Option "XkbLayout"    "us,ru"
     Option "XkbOptions"   "grp:alt_shift_toggle,grp_led:scroll"

Here, XkbOptions allows you to toggle between keyboard layouts by simply pressing Alt-Shift. This will also toggle the Scroll Lock light on or off, thanks to the grp_led:scroll option. This is a handy visual indicator of which keyboard layout you are using at the moment.

For KDE you have to install the kde-base/kde-i18n package. Kde-i18n respects LINGUAS variable described earlier.

In order to get your console to display the Euro symbol, you will need to set CONSOLEFONT in /etc/conf.d/consolefont to a file found in /usr/share/consolefonts/ (without the .psfu.gz). lat9w-16 has the Euro symbol.

CONSOLEFONT="lat9w-16"

You should verify that CONSOLEFONT is in the boot runlevel:

# rc-update show | grep -i consolefont

If no runlevel is displayed for CONSOLEFONT, then add it to the proper level:

# rc-update add consolefont boot

Getting the Euro symbol to work properly in X is a little bit tougher. The first thing you should do is change the fixed and variable definitions in /usr/X11R6/lib/X11/fonts/misc/fonts.alias to end in iso8859-15 instead of iso8859-1.

fixed        -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-15
variable     -*-helvetica-bold-r-normal-*-*-120-*-*-*-*-iso8859-15

Some applications use their own font, and you will have to tell them separately to use a font with the Euro symbol. You can do this at a user-specific level in .Xdefaults (you can copy this file to /etc/skel/ for use by new users), or at a global level for any application with a resource file in /usr/X11R6/lib/X11/app-defaults/ (like xterm). In these files you generally have to change an existing line, rather than adding a new one. To change our xterm font, for instance:

(in your home directory)
$ echo 'XTerm*font: fixed' >> .Xresources 
$ xrdb -merge .Xresources

To use the Euro symbol in (X)Emacs, add the following to .Xdefaults:

Emacs.default.attributeFont: -*-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-15

For XEmacs (not plain Emacs), you have to do a little more. In /home/user/.xemacs/init.el, add:

(define-key global-map '(EuroSign) '[€])

The current stable app-office/openoffice and app-office/openoffice-bin ebuilds support the LINGUAS variable for selecting installed GUI language packs. To see the status of GUI translation, hyphenation, spell checking and other localisations on your language, please refer to OpenOffice.Org localisation web site.