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<sections>

<abstract>
After installing and configuring a stage3, the eventual result is that you
have a Gentoo base system at your disposal. This chapter describes how
to progress to that state.
</abstract>

<version>8.1</version>
<date>2007-07-26</date>

<section>
<title>Chrooting</title>
<subsection>
<title>Optional: Selecting Mirrors</title>
<body>

<p>
In order to download source code quickly it is recommended to select a fast
mirror. Portage will look in your <path>make.conf</path> file for the
GENTOO_MIRRORS variable and use the mirrors listed therein. You can surf to
our <uri link="/main/en/mirrors.xml">mirror list</uri> and search
for a mirror (or mirrors) close to you (as those are most frequently the 
fastest ones), but we provide a nice tool called <c>mirrorselect</c> which
provides you with a nice interface to select the mirrors you want.
</p>
  
<pre caption="Using mirrorselect for the GENTOO_MIRRORS variable">
# <i>mirrorselect -i -o &gt;&gt; /mnt/gentoo/etc/make.conf</i>
</pre>

<warn>
Do not select any IPv6 mirrors. Our stages currently do not support IPv6.
</warn>

<p>
A second important setting is the SYNC setting in <path>make.conf</path>. This
variable contains the rsync server you want to use when updating your Portage
tree (the collection of ebuilds, scripts containing all the information Portage
needs to download and install software). Although you can manually enter a SYNC
server for yourself, <c>mirrorselect</c> can ease that operation for you:
</p>

<pre caption="Selecting an rsync mirror using mirrorselect">
# <i>mirrorselect -i -r -o &gt;&gt; /mnt/gentoo/etc/make.conf</i>
</pre>

<p>
After running <c>mirrorselect</c> it is adviseable to double-check the settings
in <path>/mnt/gentoo/etc/make.conf</path> !
</p>

</body>
</subsection>
<subsection>
<title>Copy DNS Info</title>
<body>

<p>
One thing still remains to be done before we enter the new environment and that
is copying over the DNS information in <path>/etc/resolv.conf</path>. You need
to do this to ensure that networking still works even after entering the new
environment. <path>/etc/resolv.conf</path> contains the nameservers for your
network.
</p>

<pre caption="Copy over DNS information">
<comment>(The "-L" option is needed to make sure we don't copy a symbolic link)</comment>
# <i>cp -L /etc/resolv.conf /mnt/gentoo/etc/</i>
</pre>

</body>
</subsection>
<subsection test="not(func:keyval('arch')='IA64')">
<title>Mounting the /proc and /dev Filesystems</title>
<body>

<p>
Mount the <path>/proc</path> filesystem on <path>/mnt/gentoo/proc</path> to
allow the installation to use the kernel-provided information within the
chrooted environment, and then mount-bind the <path>/dev</path> filesystem.
</p>

<pre caption="Mounting /proc and /dev">
# <i>mount -t proc none /mnt/gentoo/proc</i>
# <i>mount -o bind /dev /mnt/gentoo/dev</i>
</pre>

</body>
</subsection>
<subsection test="func:keyval('arch')='IA64'">
<title>Mounting the /proc, /sys and /dev Filesystems</title>
<body>

<p>
Mount the <path>/proc</path> filesystem on <path>/mnt/gentoo/proc</path> to
allow the installation to use the kernel-provided information within the
chrooted environment, and then mount-bind the <path>/dev</path> and
<path>/sys</path> filesystems.
</p>

<pre caption="Mounting /proc /sys and /dev">
# <i>mount -t proc none /mnt/gentoo/proc</i>
# <i>mount -o bind /dev /mnt/gentoo/dev</i>
# <i>mount -o bind /sys /mnt/gentoo/sys</i>
</pre>

</body>
</subsection>
<subsection>
<title>Entering the new Environment</title>
<body>

<p>
Now that all partitions are initialized and the base environment
installed, it is time to enter our new installation environment by
<e>chrooting</e> into it. This means that we change from the current
installation environment (Installation CD or other installation medium) to your
installation system (namely the initialized partitions).
</p>

<p>
This chrooting is done in three steps. First we will change the root
from <path>/</path> (on the installation medium) to <path>/mnt/gentoo</path> 
(on your partitions) using <c>chroot</c>. Then we will create a new environment
using <c>env-update</c>, which essentially creates environment variables.
Finally, we load those variables into memory using <c>source</c>.
</p>

<pre caption = "Chrooting into the new environment">
# <i>chroot /mnt/gentoo /bin/bash</i>
# <i>env-update</i>
>> Regenerating /etc/ld.so.cache...
# <i>source /etc/profile</i>
# <i>export PS1="(chroot) $PS1"</i>
</pre>

<p>
Congratulations! You are now inside your own Gentoo Linux environment.
Of course it is far from finished, which is why the installation still
has some sections left :-)
</p>

</body>
</subsection>
</section>

<section>
<title>Configuring Portage</title>
<subsection>
<title>Updating the Portage tree</title>
<body>

<p>
You should now update your Portage tree to the latest version. <c>emerge 
--sync</c> does this for you.
</p>

<pre caption="Updating the Portage tree">
# <i>emerge --sync</i>
<comment>(If you're using a slow terminal like some framebuffers or a serial
console, you can add the --quiet option to speed up this process:)</comment>
# <i>emerge --sync --quiet</i>
</pre>

<p>
If you are behind a firewall that blocks rsync traffic, you can use
<c>emerge-webrsync</c> which will download and install a portage snapshot for
you.
</p>

<p>
If you are warned that a new Portage version is available and that you should
update Portage, you should do it now using <c>emerge portage</c> command.
</p>

</body>
</subsection>
<subsection>
<title>Choosing the Right Profile</title>
<body>

<p>
First, a small definition is in place.
</p>

<p>
A profile is a building block for any Gentoo system. Not only does it specify
default values for CHOST, CFLAGS and other important variables, it also locks
the system to a certain range of package versions. This is all maintained by the
Gentoo developers.
</p>

<p>
Previously, such a profile was untouched by the users. However, there may be
certain situations in which you may decide a profile change is necessary.
</p>

<p>
You can see what profile you are currently using with the following command:
</p>

<pre caption="Verifying system profile">
# <i>ls -FGg /etc/make.profile</i>
lrwxrwxrwx  1 48 Apr  8 18:51 /etc/make.profile -> ../usr/portage/profiles/default-linux/x86/2007.0/
</pre>

<p>
The default profile will provide you with a Linux 2.6-based system. This is the
recommended default, but you have the option of choosing another profile too.
</p>

<p>
There are also <c>desktop</c> and <c>server</c> subprofiles available for some
architectures. Look inside the <path>2007.0/</path> profile to see if there is
one available for your architecture. You may wish to view the <c>desktop</c>
profile's <path>make.defaults</path> to determine if it fits your needs.
</p>

<p>
After viewing the available profiles for your architecture in
<path>/usr/portage/profiles/</path>, you can use a different one if you wish:
</p>

<pre caption="Changing profiles">
# <i>ln -snf /usr/portage/profiles/&lt;profile name&gt; /etc/make.profile</i>
</pre>

<p test="func:keyval('arch')='AMD64'">
If you want to have a pure 64-bit environment, with no 32-bit applications or
libraries, you should use a non-multilib profile:
</p>

<pre test="func:keyval('arch')='AMD64'" caption="Switching to a non-multilib profile">
# <i>ln -snf /usr/portage/profiles/default-linux/amd64/2007.0/no-multilib /etc/make.profile</i>
</pre>

</body>
</subsection>
<subsection id="configure_USE">
<title>Configuring the USE variable</title>
<body>

<p>
<c>USE</c> is one of the most powerful variables Gentoo provides to its users.
Several programs can be compiled with or without optional support for certain
items. For instance, some programs can be compiled with gtk-support, or with
qt-support. Others can be compiled with or without SSL support. Some programs
can even be compiled with framebuffer support (svgalib) instead of X11 support
(X-server).
</p>

<p>
Most distributions compile their packages with support for as much as possible,
increasing the size of the programs and startup time, not to mention an enormous
amount of dependencies. With Gentoo you can define what options a package 
should be compiled with. This is where <c>USE</c> comes into play.
</p>

<p>
In the <c>USE</c> variable you define keywords which are mapped onto
compile-options. For instance, <e>ssl</e> will compile ssl-support in the
programs that support it. <e>-X</e> will remove X-server support (note the
minus sign in front). <e>gnome gtk -kde -qt3 -qt4</e> will compile your
programs with gnome (and gtk) support, and not with kde (and qt) support,
making your system fully tweaked for GNOME.
</p>

<p>
The default <c>USE</c> settings are placed in the <path>make.defaults</path> 
files of your profile. You will find <path>make.defaults</path> files in the
directory which <path>/etc/make.profile</path> points to and all parent 
directories as well. The default <c>USE</c> setting is the sum of all <c>USE</c>
settings in all <path>make.defaults</path> files. What you place in
<path>/etc/make.conf</path> is calculated against these defaults settings. If
you add something to the <c>USE</c> setting, it is added to the default list. If
you remove something from the <c>USE</c> setting (by placing a minus sign in
front of it) it is removed from the default list (if it was in the default list
at all). <e>Never</e> alter anything inside the <path>/etc/make.profile</path>
directory; it gets overwritten when you update Portage!
</p>

<p>
A full description on <c>USE</c> can be found in the second part of the Gentoo
Handbook, <uri link="?part=2&amp;chap=2">USE flags</uri>. A full description on
the available USE flags can be found on your system in
<path>/usr/portage/profiles/use.desc</path>. 
</p>

<pre caption="Viewing available USE flags">
# <i>less /usr/portage/profiles/use.desc</i>
<comment>(You can scroll using your arrow keys, exit by pressing 'q')</comment>
</pre>

<p>
As an example we show a <c>USE</c> setting for a KDE-based system with DVD, ALSA
and CD Recording support:
</p>

<pre caption="Opening /etc/make.conf">
# <i>nano -w /etc/make.conf</i>
</pre>

<pre caption="USE setting">
USE="-gtk -gnome qt3 qt4 kde dvd alsa cdr"
</pre>

</body>
</subsection>
<subsection>
<title>Optional: glibc Locales</title>
<body>

<p>
You will probably only use one or maybe two locales on your system. You can
specify locales you will need in <path>/etc/locale.gen</path>.
</p>

<pre caption="Opening /etc/locale.gen">
# <i>nano -w /etc/locale.gen</i>
</pre>

<p>
The following locales are an example to get both English (United States) and
German (Germany) with the accompanying character formats (like UTF-8).
</p>

<pre caption="Specify your locales">
en_US ISO-8859-1
en_US.UTF-8 UTF-8
de_DE ISO-8859-1
de_DE@euro ISO-8859-15
</pre>

<p>
The next step is to run <c>locale-gen</c>. It will generate all the locales you
have specified in the <path>/etc/locale.gen</path> file.
</p>

<p>
Now continue with <uri link="?part=1&amp;chap=7">Configuring the Kernel</uri>.
</p>

</body>
</subsection>
</section>
</sections>
