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+<?xml version="1.0" encoding="ISO-8859-1"?>
+<chapter id="using_enealinux">
+  <title>Using Enea Linux</title>
+  <section id="build_enealinux">
+    <title>Building Enea Linux</title>
+    <para>Enea Linux is made available as sources, this allows for of building
+    various Enea Linux artifacts and is detailed in the following
+    sections:</para>
+    <section id="build_images">
+      <title>Building the images</title>
+      <para>Build Enea Linux images using the following steps:</para>
+      <procedure>
+        <step>
+          <para>Set the $MACHINE/&lt;machine&gt; variable to the target you
+          need, e.g. <literal>intel-corei7-64</literal>.</para>
+        </step>
+        <step>
+          <para>Clone Enea Linux sources using Repo tool. Please refer to
+          <xref linkend="getting_sources" /> for more details.</para>
+          <programlisting>$ mkdir enea-linux
+$ cd enea-linux
+$ repo init -u git@git.enea.com:linux/manifests/el_manifests-rt.git \
+    -b refs/tags/Enea_Linux_8.0 -m $MACHINE/default.xml
+$ repo sync</programlisting>
+        </step>
+        <step>
+          <para>Source the build environment</para>
+          <programlisting>$ cd poky 
+$ TEMPLATECONF=meta-el-rt/conf/template.&lt;machine&gt; \
+. ./oe-init-build-env &lt;build_dir&gt;</programlisting>
+          <para>Sourcing the build environment is needed everytime a new shell
+          is used. However, sourcing using the <literal>TEMPLATECONF</literal>
+          is only needed the first time around. After the first time, it is
+          enough to source the build directory created before.</para>
+          <note>
+            <para>The build directory may reside on an NFS mount, but the
+            <literal>TMPDIR</literal>
+            (<literal>&lt;build_dir&gt;/tmp</literal>) may not. Either build
+            all on a local disk, or update <literal>TMPDIR</literal> in
+            <literal>conf/local.conf</literal> to point to a local
+            disk.</para>
+          </note>
+        </step>
+        <step>
+          <para>Build Enea Linux image</para>
+          <programlisting># You have already initiated the build environment and are in the &lt;build_dir&gt;
+$ bitbake &lt;enea-image-name&gt; 
+$ cd &lt;build_dir&gt;/tmp/deploy/images/&lt;target&gt;/  # Here are the build binaries</programlisting>
+          <note>
+            <para>Some builds have restrictions on the length of the path
+            name. If you get a build error indicating that the length is too
+            long, you need to move your build to obtain a shorter path.</para>
+          </note>
+          <para>Generated images are by default saved in
+          <literal><literal>&lt;build_dir&gt;/tmp/deploy/images/&lt;target&gt;</literal></literal>,
+          where <literal>&lt;build_dir&gt;</literal> by default is the current
+          working directory. Images are created for emulation on host or for
+          booting a physical target, according to how the build environment
+          was set up before running bitbake.</para>
+          <para>Depending on the number of processors and cores, the amount or
+          RAM, the speed of your Internet connection and other factors, the
+          build process can take several hours the first time you run it.
+          Subsequent builds run much faster since parts of the build are
+          cached.</para>
+          <note>
+            <para>Make sure that the user running the build has access to the
+            Git repositories on git.enea.com. The build process fetches
+            information from git.enea.com so the user running the build shall
+            have the ssh key properly configured. Please refer to <xref
+            linkend="getting_sources" /> for more details on how to get access
+            to Enea Linux sources.</para>
+          </note>
+        </step>
+      </procedure>
+    </section>
+    <section id="build_sdk">
+      <title>Building the SDK</title>
+      <para>If you want to rebuild a cross-compilation toolchain to be used by
+      in application development, use the following steps:</para>
+      <procedure>
+        <step>
+          <para>Clone Enea Linux sources using Repo tool. Please refer to
+          <xref linkend="getting_sources" /> for more details on how to do
+          this.</para>
+          <programlisting>$ mkdir enea-linux
+$ cd enea-linux
+$ repo init -u git@git.enea.com:linux/manifests/el_manifests-rt.git \
+    -b refs/tags/Enea_Linux_8.0 -m $MACHINE/default.xml
+$ repo sync</programlisting>
+        </step>
+        <step>
+          <para>Source the build environment</para>
+          <programlisting>$ cd poky 
+$ TEMPLATECONF=meta-el-rt/conf/template.&lt;machine&gt; \
+. ./oe-init-build-env &lt;build_dir&gt;</programlisting>
+          <para>Sourcing the build environment is needed everytime a new shell
+          is used. However, sourcing using the <literal>TEMPLATECONF</literal>
+          is only needed the first time around. Afterwards it is enough to
+          source the build directory created before.</para>
+          <note>
+            <para>The build directory may reside on an NFS mount, but the
+            <literal>TMPDIR</literal>
+            (<literal>&lt;build_dir&gt;/tmp</literal>) may not. Either build
+            all on a local disk, or update TMPDIR in conf/local.conf to point
+            to a local disk.</para>
+          </note>
+        </step>
+        <step>
+          <para>Build Enea Linux SDK</para>
+          <programlisting># You have already initiated the build environment and are in the &lt;build_dir&gt;
+$ bitbake &lt;enea-image-name&gt; -c populate_sdk_ext 
+$ cd &lt;build_dir&gt;/tmp/deploy/sdk/  # Here is the SDK installer script</programlisting>
+          <note>
+            <para>Some builds have restrictions on the length of the path
+            name. If you get a build error indicating that the length is too
+            long, you need to move your build to obtain a shorter path.</para>
+          </note>
+          <para>Generated SDK installer script is by default saved in
+          <literal>&lt;build_dir&gt;/tmp/deploy/sdk</literal>, where
+          <literal>&lt;build_dir&gt;</literal> by default is the current
+          working directory.</para>
+          <para>Depending on the number of processors and cores, the amount or
+          RAM, the speed of your Internet connection and other factors, the
+          build process can take several hours the first time you run it.
+          Subsequent builds run much faster since parts of the build are
+          cached.</para>
+          <para>For more details on how to install and use the SDK, please
+          refer to <xref linkend="install_el_sdk" />.</para>
+        </step>
+      </procedure>
+    </section>
+  </section>
+  <section id="boot_enealinux">
+    <title>Booting Enea Linux</title>
+    <para>Regardless whether you decide to use the pre-built images or if you
+    choose to build your own, the end result should be similar. Once you have
+    the artifacts availalbe, you may proceed to booting Enea Linux on
+    target.</para>
+    <para>Enea Linux supports multiple booting methods so those will be
+    described in the following sections.</para>
+    <section id="enea-linux-x86-pxe">
+      <title>Boot via PXE using DHCP, TFTP, and NFS servers</title>
+      <para>Below you find an example of how to boot Enea Linux in a target
+      supporting PXE. The PXE boot is handled by the target BIOS.</para>
+      <para>This requires the setup of DHCP, TFTP and NFS servers on the host.
+      The DHCP server contains a configuration for the target, found via the
+      target MAC address, and refers to the TFTP server for the boot image and
+      to the NFS server for the root file system.</para>
+      <para>For the DHCP server, in addition to the general configuration, the
+      DHCPD configuration should contain an entry for the target with the
+      following information:</para>
+      <itemizedlist spacing="compact">
+        <listitem>
+          <para>Host name</para>
+        </listitem>
+        <listitem>
+          <para>MAC hardware ethernet address (also available in the TFTP
+          configuration)</para>
+        </listitem>
+        <listitem>
+          <para>IP address, (assuming a fixed IP address is used)</para>
+        </listitem>
+        <listitem>
+          <para>The TFTP server shall be defined as
+          <literal>next-server</literal></para>
+        </listitem>
+        <listitem>
+          <para>The relative path in the TFTP server to the PXE file
+          <filename><literal>pxelinux.0</literal></filename></para>
+        </listitem>
+        <listitem>
+          <para>The NFS server IP address and the path to the rootfs on the
+          NFS server, defined as <literal>option root-path</literal></para>
+        </listitem>
+      </itemizedlist>
+      <para>Example of a DHCP server configuration:</para>
+      <programlisting>host intel-corei7-64_host {
+    hardware ethernet 01:00:25:90:c8:c5:98;
+    fixed-address     192.168.1.38;
+    next-server       192.168.2.10;
+    filename          "intel-corei7-64_tftp/pxelinux.0";
+    option root-path  "192.168.2.20:/export/intel-corei7-64_rootfs";
+}</programlisting>
+      <para>For the TFTP server, the TFTP path to the target's pxelinux.0 file
+      is given in the DHCP Configuration. Examples of files included in the
+      TFTP subdirectory indicated by the DHCP configuration are:</para>
+      <programlisting>pxelinux.0
+vesamenu.c32
+boot/device01/bzImage                          (bootable image file)
+pxelinux.cfg/01-00-25-90-c8-c5-98              (Configuration file)</programlisting>
+      <para>One configuration file has the same name as the target's MAC
+      address (but with hyphens instead of a colon). This configuration file
+      contains a pointer to the bootable image and also a list of command line
+      arguments to append when the image is started. The same NFS path to the
+      root file system is both in the DHCP and the TFTP configuration.</para>
+      <para>Example of a configuration file:</para>
+      <programlisting>default vesamenu.c32
+prompt 0
+timeout 100
+label device01
+  menu label ^EneaLinuxNFS
+  menu default
+  kernel boot/device01/bzImage
+  <emphasis role="bold">append</emphasis> root=/dev/nfs nfsmount=192.168.2.20:/export/intel-corei7-64_rootfs ip=dhcp
+                                                            console=ttyS0,115200</programlisting>
+      <para><emphasis role="bold">NFS server</emphasis>: The NFS server shall
+      contain an unpacked root file system in the path indicated both in the
+      DHCP and in the TFTP configuration.</para>
+      <para>After configuring the servers, copy files from the build directory
+      into the correctly configured paths:</para>
+      <orderedlist spacing="compact">
+        <listitem>
+          <para>Ensure the target is not already running an OS, otherwise the
+          target might attempt to change files on the root file system while
+          it is populated with new files.</para>
+        </listitem>
+        <listitem>
+          <para>Copy <filename>pxelinux.0</filename> and
+          <filename>vesamenu.c32</filename> from the build directory, e.g.
+          from
+          <filename>&lt;build_dir&gt;tmp/work/corei7-64-enea-linux/syslinux/6.03-r0/image/usr/share/syslinux/</filename>.</para>
+        </listitem>
+        <listitem>
+          <para>Copy <filename>bzImage</filename> from
+          <filename>&lt;build_dir&gt;/tmp/deploy/images/&lt;target&gt;/</filename>.</para>
+        </listitem>
+        <listitem>
+          <para>Populate the root file system in the NFS directory by
+          unpacking
+          <filename>enea-image-rt-intel-corei7-64.tar.gz</filename>
+          found at
+          <filename>&lt;build_dir&gt;/tmp/deploy/images/&lt;target&gt;/</filename>.</para>
+        </listitem>
+      </orderedlist>
+      <para>Boot the target by:</para>
+      <orderedlist>
+        <listitem>
+          <para>Use the BIOS or boot setup to select PXE boot, if not already
+          selected.</para>
+        </listitem>
+        <listitem>
+          <para>Reboot the target.</para>
+        </listitem>
+      </orderedlist>
+      <para>The boot setup menu is usually launched by pressing F12 or ESC
+      during BIOS power up tests. Look up the manufacturer's documentation for
+      your board model to find the appropriate key.</para>
+    </section>
+  </section>
+  <section id="custom_enealinux">
+    <title>Customizing Enea Linux</title>
+    <section id="layers_adaptations">
+      <title>Layers and Adaptations</title>
+      <para>Bitbake allows a modular approach of Metadata, by building images
+      for the layers listed in the conf/bblayers.conf file from your build
+      directory.</para>
+      <para>To avoid polluting the build with unnecessary packages, before
+      adding a new layer, it is recommended to check if the Metadata you need
+      is already available in the enabled layers, in which case, for the
+      intended configuration, it may require less modification.</para>
+      <para>To ease further use of the layer, try to follow as many best
+      practices as possible when creating it:</para>
+      <itemizedlist>
+        <listitem>
+          <para>Use names starting with the meta prefix (although this is not
+          a requirement)</para>
+        </listitem>
+      </itemizedlist>
+      <itemizedlist>
+        <listitem>
+          <para>Place your layer under poky</para>
+        </listitem>
+      </itemizedlist>
+      <itemizedlist>
+        <listitem>
+          <para>Isolate different customizations by layer</para>
+        </listitem>
+      </itemizedlist>
+      <itemizedlist>
+        <listitem>
+          <para>Assign the layer to a repository (to easily have access to
+          maintenance)</para>
+        </listitem>
+      </itemizedlist>
+      <para>To enable a layer, its top path must be specified in the
+      <filename>BBLAYERS</filename> variable, as follows:</para>
+      <programlisting># POKY_BBLAYERS_CONF_VERSION is increased each time build/conf/bblayers.conf
+# changes incompatibly
+POKY_BBLAYERS_CONF_VERSION = "2"
+BBPATH = "${TOPDIR}"
+BBFILES ?= ""
+BBLAYERS ?= " \
+  /path/to/poky/meta \
+  /path/to/poky/meta-el-common \
+  /path/to/poky/meta-el-rt \
+  /path/to/poky/meta-enea-bsp-common \
+  /path/to/poky/meta-enea-bsp-x86 \
+  /path/to/poky/meta-openembedded/meta-oe \
+  /path/to/poky/meta-openembedded/meta-networking \
+  /path/to/poky/meta-openembedded/meta-filesystems \
+  /path/to/poky/meta-openembedded/meta-python \
+  /path/to/poky/meta-poky \
+  /path/to/poky/meta-&lt;layer&gt; \
+  "</programlisting>
+      <para>Before adding an extra layer, please keep in mind that the order
+      of layers is important (due to BitBake parsing conf/layer.conf as
+      specified in <filename>BBLAYERS</filename>). To add an extra layer, you
+      can modify the <filename>build/conf/bblayers.conf</filename> file in the
+      source code editor you prefer, as described above, or use one of the
+      specially designed Yocto tools.</para>
+      <para>To do such, you can simply modify the build/conf/bblayers.conf
+      file in the source code editor you prefer, as described above, or use
+      one of the specially designed Yocto tools.</para>
+      <para>For instance, in addition to the above, the Yocto Bitbake layers
+      utility ensures a very useful checking of some basic layer requirements.
+      Bitbake layers are available, as most of the BitBake tools, when
+      sourcing oe-init-build-env. Therefore, to enable a custom meta layer,
+      you should simply run the following from the build directory:</para>
+      <programlisting>bitbake-layers add-layer &lt;meta-layer&gt;</programlisting>
+      <para>If the specified layer doesn't contain a
+      <filename>conf/layer.conf</filename> file, you should add one with the
+      needed configuration. Also, to make sure the layer insertion is done in
+      the right metadata, the utility looks for the bblayers.conf
+      configuration file in the corresponding path, which should be satisfied
+      if running the command from the generated build directory.</para>
+      <para>For further information on this or on other utilities belonging to
+      the same suite, run:</para>
+      <programlisting>bitbake-layers -h</programlisting>
+      <para>As a result, <filename>BBLAYERS</filename> shall be extended with
+      the bsp-layer/s layer for your target and any other additional layer/s.
+      For details on how to do this, see the <ulink
+      url="http://www.yoctoproject.org/docs/2.5/dev-manual/dev-manual.html#understanding-and-creating-layers">Yocto
+      2.5 Dev Manual, section "Understanding and Creating Layers".</ulink> If
+      needed replace the Yocto version.</para>
+      <para>Layers can be added when you initialize the build environment. The
+      layers required for each target are specified in the build commands in
+      the Enea Linux distribution's Release Information.</para>
+      <para>Each Enea Linux customer is advised to add a custom layer for
+      customer-specific additions and customizations, instead of modifying
+      existing layers.</para>
+      <para>The recommended way to modify a package is to edit directly in the
+      recipe file. Utilizing the devshell, <literal>bitbake -c devshell
+      &lt;image_name&gt;</literal>, when constructing or modifying recipes is
+      really handy when experimenting, but do not forget to make the final
+      updates directly in the recipe file. It is difficult to keep track of
+      exactly what in the user environment is "dirty" and not in sync with
+      current recipes. Therefore, always make sure to <literal>bitbake -c
+      clean &lt;image_name&gt;</literal> after finishing up a devshell
+      session, and adapt recipes accordingly to ensure a shareable and
+      repeatable build environment.</para>
+    </section>
+    <section id="add_recipe">
+      <title>Adding a Recipe</title>
+      <para>Study the <ulink
+      url="https://www.yoctoproject.org/docs/2.5/dev-manual/dev-manual.html#new-recipe-single-c-file-package-hello-world"><ulink
+      url="https://www.yoctoproject.org/docs/2.5/dev-manual/dev-manual.html#new-recipe-single-c-file-package-hello-world">Hello
+      World recipe</ulink></ulink> in the Yocto Project Development Manual. If
+      needed replace the example version (2.5) with the Yocto version in your
+      Enea Linux distribution.</para>
+    </section>
+    <section id="config_pkg_recipes">
+      <title>Configuring Packages via Recipes</title>
+      <para>The default configuration produces a standard Linux installation,
+      but it is often desirable to configure specific packages in more detail.
+      Different packages implement their configuration in different ways, and
+      there is no single method that is valid for all packages. As always, in
+      a collaborative development environment, the developer should make sure
+      that the recipes in the custom layer are upgraded accordingly when a
+      reconfiguration of a specific package is done.</para>
+      <para>In subsequent sections you find examples on how to configure some
+      common packages.</para>
+      <section id="linux_kern">
+        <title>The Linux Kernel</title>
+        <para>The Linux kernel provides a vast array of configuration options,
+        managed using its own configuration system. The kernel package can be
+        supplied from different providers, and this example uses the
+        virtual/kernel package name to refer to the kernel used in the
+        build:</para>
+        <programlisting>$ bitbake -c menuconfig virtual/kernel</programlisting>
+        <note>
+          <para>menuconfig requires Ncurses. If the terminal that pops up
+          immediately closes instead of showing the menuconfig interface,
+          check that the Ncurses development library is installed.</para>
+        </note>
+        <para>First build the kernel:</para>
+        <programlisting>$ bitbake -f -c compile -c install -c deploy virtual/kernel</programlisting>
+        <para>Then build the whole distribution:</para>
+        <programlisting>$ bitbake enea-image-&lt;name&gt;</programlisting>
+      </section>
+      <section id="busybox">
+        <title>Busybox</title>
+        <para>Busybox uses the same configuration system as the Linux kernel
+        and is therefore invoked similarly. In contrast to the kernel, there
+        is generally only one variant of busybox in a distribution and we can
+        therefore refer to it by the package name alone:</para>
+        <programlisting>$ bitbake -c menuconfig busybox</programlisting>
+      </section>
+    </section>
+    <section id="build_com_licenses">
+      <title>Building with Commercial Licenses</title>
+      <note>
+        <para>Adding commercial-licensed packages might pose distribution
+        problems due to license agreements or patents.</para>
+      </note>
+      <para>Commercial-licensed packages are not provided with Enea Linux.
+      Depending on your use case, you might need to extend the initial image
+      with more packages by adding recipes and updating the image definition,
+      always in accordance with the license conditions. To succeed with
+      building the customized image, you might need to solve dependencies by
+      adding even more packages.</para>
+      <para>Below is an example with steps on how to add a package with a
+      commercial license. The configuration is updated in two places and the
+      recipes are selected for the packages and any dependencies.</para>
+      <note>
+        <para>This is only an illustrating example, the exact configuration
+        may differ between different packages. Some packages could require
+        other defines added to local.conf and some packages might need an
+        added <filename>DEPENDS</filename> in the *.inc file, or other
+        particular changes.</para>
+      </note>
+      <itemizedlist>
+        <listitem>
+          <para>Append the package name to the
+          <filename>IMAGE_INSTALL</filename> definition, used in the recipe
+          corresponding to the image you will build, as in one of the examples
+          below:</para>
+          <orderedlist>
+            <listitem>
+              <para>If you need the package in a set of images, to avoid
+              defining it in each recipe, add the following line to
+              <filename>IMAGE_INSTALL</filename> in
+              <filename>meta-el-common/images/enea-image-common.inc</filename></para>
+              <programlisting>  package_name \</programlisting>
+            </listitem>
+            <listitem>
+              <para>If you have specific images in which you need the package,
+              add the following line in the corresponding recipes in
+              meta-el-&lt;profile&gt;/images/enea-image-&lt;profile&gt;.bb</para>
+              <programlisting>  IMAGE_INSTALL += " \
+          package_name \
+          "</programlisting>
+            </listitem>
+          </orderedlist>
+        </listitem>
+        <listitem>
+          <para>Add the required license to the
+          <filename>LICENSE_FLAGS_WHITELIST</filename> definition. This can be
+          done by adding script lines in the corresponding
+          scripts/conf_setup.sh file, which appends
+          <filename>LICENSE_FLAGS_WHITELIST +=
+          "&lt;suitable-license&gt;</filename> to
+          <filename>conf/local.conf.</filename></para>
+        </listitem>
+        <listitem>
+          <para>To mitigate the build errors caused by packages with
+          commercial licenses, you might also need to append the generic
+          license <filename>LICENSE_FLAGS_WHITELIST += "commercial"</filename>
+          in the same way as above.</para>
+        </listitem>
+        <listitem>
+          <para>Select the needed recipes for the packages and add these to
+          the build configuration.</para>
+        </listitem>
+        <listitem>
+          <para>Select the needed recipes to resolve dependencies for the new
+          packages and add these to the build configuration.</para>
+        </listitem>
+      </itemizedlist>
+      <para>More information about recipes can be found here:</para>
+      <itemizedlist>
+        <listitem>
+          <para><ulink
+          url="http://git.openembedded.org/">http://git.openembedded.org/</ulink></para>
+        </listitem>
+      </itemizedlist>
+      <itemizedlist>
+        <listitem>
+          <para><ulink
+          url="https://wiki.yoctoproject.org/wiki/Building_your_own_recipes_from_first_principles">https://wiki.yoctoproject.org/wiki/Building_your_own_recipes_from_first_principles</ulink></para>
+        </listitem>
+      </itemizedlist>
+      <itemizedlist>
+        <listitem>
+          <para><ulink
+          url="http://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#new-recipe-writing-a-new-recipe">http://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#new-recipe-writing-a-new-recipe</ulink></para>
+        </listitem>
+      </itemizedlist>
+    </section>
+  </section>
+  <section id="install_el_sdk">
+    <title>Installing the Enea Linux SDK</title>
+    <para>Before cross-compiling applications for your target, you need to
+    install the Software Development Kit (SDK) - which contains the
+    cross-compilation toolchain - and set up the cross-compilation environment
+    on your host. The toolchain for each supported target contains a 64-bit
+    library for gcc. The toolchain and the environment-setup script are
+    wrapped together inside a toolchain installer in the form of a shell
+    script.</para>
+    <para>The cross-compilation toolchain is packaged as follows:</para>
+    <itemizedlist>
+      <listitem>
+        <para>The &lt;target&gt; toolchain contains the lib64 (64-bit)
+        library.</para>
+      </listitem>
+      <listitem>
+        <para>The &lt;target&gt; installer has an environment-setup script
+        which will select the lib64 to be used by gcc. This way, a 64-bit
+        application can be cross-compiled.</para>
+      </listitem>
+    </itemizedlist>
+    <para>Do as in the example below to install the SDK and set up the
+    cross-compilation environment:</para>
+    <orderedlist>
+      <listitem>
+        <para>The fastest alternative is to use a precompiled
+        cross-compilation toolchain installer for your host and target.</para>
+        <para>Please refer to the Release Information document, in section 1.1
+        Provided Contents, for more details on where to find the pre-compiled
+        SDK installer.</para>
+      </listitem>
+      <listitem>
+        <para>Run the installer to unpack the cross-compilation toolchain and
+        the environment-setup script:</para>
+        <programlisting>$ chmod 770 enea-*-toolchain-&lt;version&gt;.sh
+$ ./enea-*-toolchain-&lt;version&gt;.sh</programlisting>
+        <para>When prompted, select to install the SDK in the desired
+        directory, referred to as &lt;sdkdir&gt;. The default path where the
+        SDK will be installed, will be shown in the prompt. The installer
+        unpacks the environment setup script in &lt;sdkdir&gt; and the
+        toolchain under &lt;sdkdir&gt;/sysroots.</para>
+        <note>
+          <para>Choose a unique directory for each toolchain. Installing a
+          second toolchain of any type (buildtools toolchain or
+          cross-compilation toolchain) in the same directory as a previously
+          installed one will break the $PATH variable of the first one.</para>
+        </note>
+      </listitem>
+      <listitem>
+        <para>Setup the toolchain environment for your target by sourcing the
+        environment-setup script:</para>
+        <programlisting>$ . &lt;sdkdir&gt;/environment-setup-&lt;arch&gt;-enea-linux</programlisting>
+        <para>Example:</para>
+        <programlisting>$ . /opt/enea/environment-setup-corei7-64-enea-linux</programlisting>
+      </listitem>
+    </orderedlist>
+    <para>Once the cross-compilation toolchain is in place and the environment
+    set up, you can proceed with Cross-Compiling Applications from Command
+    Line (4.1) or, if Eclipse is installed, Cross-Compiling from Eclipse
+    (5.4.1).</para>
+  </section>
+  <section id="pkg_mg">
+    <title>Using Package Management</title>
+    <para>A Package Management System (PMS) can be used to customize your
+    image in a consistent way, e.g. to install, upgrade, or delete packages
+    considering the dependencies. The package management systems supported by
+    Enea Linux are described in this section. More information about PMS can
+    be found in the Yocto 2.5 document <ulink
+    url="http://www.yoctoproject.org/docs/2.5/mega-manual/mega-manual.html">Yocto
+    Project Mega Manual</ulink>. If needed replace the Yocto version in the
+    link.</para>
+    <section id="apt_pktmgmt">
+      <title>APT Package Management (DEB Packages)</title>
+      <para>Enea Linux provides DEB packages on <ulink
+      url="http://linux.enea.com/EneaLinux8.0/">linux.enea.com</ulink> site,
+      in directory
+      <literal><literal>&lt;release&gt;/&lt;target&gt;/deb</literal>/</literal>.</para>
+      <para>The application for performing runtime package management of DEB
+      packages on the target is called <filename>apt-get</filename>.</para>
+      <para>Use the <literal>apt-get</literal> command to install, upgrade, or
+      remove packages. Before using any apt-get options that require network
+      access, please check that the network is configured and working
+      properly.</para>
+      <para>The <literal>apt-get</literal> command is by default included in
+      Enea Linux images.</para>
+      <section id="apt_config">
+        <title>Configuring</title>
+        <para>APT relies on the concept of repositories in order to find
+        packages and resolve dependencies.</para>
+        <para>Any number of additional repositories can be added to APT's
+        configuration files (.list extension) located in sources.list.d
+        directory (e.g:
+        <filename>/etc/apt/sources.list.d/repos.list</filename>) and then be
+        queried by APT.</para>
+        <programlisting># touch /etc/apt/sources.list.d/repos.list
+# echo "deb [trusted=yes]  http://server-address/path/to/the/package/directory ./" | \
+tee -a /etc/apt/sources.list.d/repos.list</programlisting>
+        <para>Run <literal>apt-get update</literal> to fetch information from
+        the new repository:</para>
+        <programlisting># apt-get update</programlisting>
+      </section>
+      <section id="apt_install">
+        <title>Installing</title>
+        <para>DEB packages typically have file names like
+        foo-1.0.1-r0.0_arm64.deb The file name includes the package name
+        (foo), version (1.0.1), revison (r0.0), and architecture (arm64). To
+        install a package, log in as root and type the following command at a
+        shell prompt:</para>
+        <programlisting># apt-get install foo</programlisting>
+        <para>The <literal>apt-get install</literal> command will install one
+        or more packages in the system.</para>
+      </section>
+      <section id="apt_upgrade">
+        <title>Upgrading</title>
+        <para>The <literal>apt-get upgrade</literal> command will upgrade one
+        or more packages which are currently installed in the system. If no
+        packages are given, all installed packages will be checked.</para>
+        <programlisting># apt-get upgrade foo</programlisting>
+      </section>
+      <section id="apt_rm">
+        <title>Removing</title>
+        <para>The <literal>apt-get remove</literal> command will remove one or
+        more packages which are currently installed in the system.
+        Example:</para>
+        <programlisting># apt-get remove ptest-runner
+Reading package lists... Done
+Building dependency tree
+Reading state information... Done
+The following packages were automatically installed and are no longer required:
+  libc6-dbg libc6-dev libc6-extra-nss libc6-thread-db libcidn1
+  linux-libc-headers-dev
+Use 'apt autoremove' to remove them.
+The following packages will be REMOVED:
+  ptest-runner
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+After this operation, 0 B of additional disk space will be used.
+Do you want to continue? [Y/n] y
+(Reading database ... 5766 files and directories currently installed.)
+Removing ptest-runner (2.0.2+git0+6d2872116c-r0.0) ...
+</programlisting>
+      </section>
+      <section id="pm_searching">
+        <title>Searching</title>
+        <para>The <literal>apt-cache search</literal> allows searching for the
+        given expressions in the name, summary and description of known
+        packages. Example:</para>
+        <programlisting># apt-cache search ptest-runner
+ptest-runner - A C program to run all installed ptests
+ptest-runner-dbg - A C program to run all installed ptests - Debugging files
+ptest-runner-dev - A C program to run all installed ptests - Development files</programlisting>
+      </section>
+    </section>
+  </section>
+</chapter>