<sect1 id="scripts-bash-environment">

    <title>Execution Environments</title>

    <para>

        This section describes both variables and functions used by

        <command>centos-art.sh</command> script as well as the related

        execution environments they take place on.

    </para>

    <para>

        The execution environment of <command>centos-art.sh</command>

        script can be defined as the virtual boundery of memory in

        which the script does what it was conceived to do once

        executed by a command-line interpreter (e.g., Bash). When you

        execute the <command>centos-art.sh</command> script in your

        terminal, the interpreter behind it creates a new execution

        environment for it which inherits all the variables and

        functions set in the shell execution environment and those

        exported to it through the

        <filename>~/.bash_profile</filename> file, as well.

    </para>

    <para>

        The <command>centos-art.sh</command> script uses the

        <filename>~/.bash_profile</filename> file to implement

        per-user customizations.  For example, you can use this file

        to set the location of your working copy through the

        <envar>TCAR_WORKDIR</envar> enviroment variable. By default

        this variable is set to 

        class="directory">${HOME}/artwork</filename>, but you can

        reset to something different to fit your needs. See 

        linkend="repo-ws-config-ChangeWorkingCopy" />.

    </para>

    <para>

        Once the <command>centos-art.sh</command> script has been

        executed, it creates different levels of execution

        environments inside the one created by the script itself on

        the shell.  This different levels can be seen as a tree of

        execution environments which inherit one another, as

        illustrated in <xref linkend="scripts-bash-environments-1" />.

        These different levels of execution evironments are where the

        <command>centos-art.sh</command> script is developed in.

    </para>

    <example id="scripts-bash-environments-1">

    <title>Execution environments</title>

    <screenshot>

    <screeninfo>Execution environments</screeninfo>

    <mediaobject>

    <textobject>

<programlisting>

---------------------------------------------------------------

Shell execution environment

----|-------------------|--------------------------------------

.   |-- TCAR_WORKDIR    |-- EDITOR                            .

.   |-- LANG            |-- HOME                              .

.   `-- centos-art.sh   `-- ...                               .

.       ----|------------------------------------------------ .

.       centos-art.sh script execution environment            .

.       ----|--------------------|--------------------------- .

.       .   |-- CLI_NAME         `-- cli()                  . .

.       .   |-- CLI_VERSION          |-- render()           . .

.       .   |-- CLI_BASEDIR          |   |-- svg()          . .

.       .   |-- CLI_FUNCDIR          |   `-- docbook()      . .

.       .   |-- TMPDIR               |-- help()             . .

.       .   `-- ...                  |   |-- docbook()      . .

.       .                            |   `-- texinfo()      . .

.       .                            |-- locale()           . .

.       .                            |-- cli_printMessage() . .

.       .                            |-- cli_getFilesList() . .

.       .                            `-- ...                . .

.       ..................................................... .

...............................................................

</programlisting>

    </textobject>

    </mediaobject>

    </screenshot>

    </example>

    <para>

        The first file <command>centos-art.sh</command> script calls

        is the

        <filename>trunk/Scripts/Bash/Functions/Common/cli.sh</filename>

        file. This file initializes variables and functions used along

        the script execution environment.  Such variables are for

        internal use inside the <command>centos-art.sh</command>

        script only and users shouldn't modify them to customize the

        script in a per-user level.  Instead, to customize the script

        behaviour in a per-user level, users need to make use of

        environment variables set in

        <filename>~/.bash_profile</filename> file.

    </para>

    <para>

        The functions initialized by

        <filename>trunk/Scripts/Bash/Functions/Common/cli.sh</filename>

        can be either common or specific. Common functionalities are

        always loaded in each execution of centos-art.sh script.

        Common functionalities are stored in the 

        class="directory">trunk/Scripts/Bash/Functions/Commons/</filename>

        directory and are made available for all specific

        functionalities loaded later. Specific functionalities, on the

        other hand, are loaded based in the first argument passed to

        <command>centos-art.sh</command> script and are not available

        for common functionalities. Specific functionalities are

        stored in the 

        class="directory">trunk/Scripts/Bash/Functions/${CLI_FUNCDIRNAM}</filename>

        directory.

    </para>

    <para>

        In <xref linkend="scripts-bash-environments-1" />,

        <function>render</function>, <function>help</function> and

        <function>locale</function> are all specific functions while

        <function>cli_printMessage</function> and

        <function>cli_getFilesList</function> are common

        functionality.

    </para>

    <sect2 id="scripts-bash-environments-variables">

    <title>Environment Variables</title>

    <para>

        The <command>centos-art.sh</command> script uses the following

        system environment variables:

    </para>

    <variablelist>

    <varlistentry>

    <term><envar>PATH</envar></term>

    <listitem>

    <para>

        The <envar>PATH</envar> environment variable is specific to

        the operating system and provides search paths for command

        execution.  By default, the centos-art.sh script links

        executable scripts from the 

        class="directory">~/bin</filename> directory which is one of

        the locations used as search path in this variable. This is

        how we create the <command>centos-art</command> command from

        the <command>centos-art.sh</command> script  inside your

        working copy.

    </para>

    <para>

        This variable is not initialized inside the

        <command>centos-art.sh</command> script. Instead, the value

        set in <filename>~/.bash_profile</filename> file is used. 

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><envar>EDITOR</envar></term>

    <listitem>

    <para>

        The <envar>EDITOR</envar> environment variable is specific to

        the operating system and provides the path to your default

        text editor. The <command>centos-art.sh</command> script uses

        the default text editor to edit subversion pre-commit

        messages, translation files, documentation files, script

        files, and similar text-based files.  

    </para>

    <para>

        Possible values for this variable are:

    </para>

    <itemizedlist>

        <listitem>

        <para>

            <filename class="directory">/usr/bin/vim</filename>

        </para>

        </listitem>

        <listitem>

        <para>

        <filename class="directory">/usr/bin/emacs</filename>

        </para>

        </listitem>

        <listitem>

        <para>

            <filename class="directory">/usr/bin/nano</filename>

        </para>

        </listitem>

    </itemizedlist>

    <para>

        In case none of these values is set for the

        <envar>EDITOR</envar> environment variable inside

        <filename>~/.bash_profile</filename>, the

        <command>centos-art.sh</command> script uses 

        class="directory">/usr/bin/vim</filename> as default text

        editor. This is the default text editor installed by default

        in &TC;;. 

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>TEXTDOMAIN</varname></term>

    <listitem>

    <para>

        The <envar>TEXTDOMAIN</envar> environment variable is specific

        to the operating system and provides the domain name of that

        application we are producing translation messages for. This

        variable, in combination with <envar>TEXTDOMAINDIR</envar>, is

        used by <application>gettext</application> to find out the

        location of translation messages.  In the very specific case

        of <command>centos-art.sh</command> script we use the

        <literal>centos-art.sh</literal> name as domain name.

    </para>

    <para>

        This variable is initialized inside the

        <command>centos-art.sh</command> script, so if you set it

        outside it (e.g., in <filename>~/.bash_profile</filename>) the

        value you set there will be overwritten by that one set inside

        <command>centos-art.sh</command> script, once it is executed.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>TEXTDOMAINDIR</varname></term>

    <listitem>

    <para>

        The <envar>TEXTDOMAINDIR</envar> environment variable is

        specific to the operating system and provides the absolute

        path to the directory containing the translation messages

        related to that application specified by

        <envar>TEXTDOMAIN</envar> environment variable.  In the very

        specific case of <command>centos-art.sh</command> script we

        use the 

        class="directory">trunk/Locales/Scripts/Bash</filename>

        path as default value.

    </para>

    <para>

        This variable is initialized inside the

        <command>centos-art.sh</command> script, so if you set it

        outside it (e.g., in <filename>~/.bash_profile</filename>) the

        value you set there will be overwritten by that one set inside

        <command>centos-art.sh</command> script, once it is executed.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><envar>TMPDIR</envar></term>

    <listitem>

    <para>

        The <envar>TMPDIR</envar> environment variable is specific to

        the operating system and provides the absolute path to the

        temporal directory the centos-art.sh script will use along its

        execution. This variable is defined inside the

        <command>centos-art.sh</command> script itself using the

        <command>mktemp</command> command and will be unique on each

        script execution. Thus, you should be able to run several

        instances of <command>centos-art.sh</command> script

        simultaneously without any problem. 

    </para>

    <para>

        Each time you need to store temporal files, do it inside the

        absolute path specified by this variable.

    </para>

    <para>

        This variable is initialized inside the

        <command>centos-art.sh</command> script, so if you set it

        outside it (e.g., in <filename>~/.bash_profile</filename>) the

        value you set there will be overwritten by that one set inside

        <command>centos-art.sh</command> script, once it is executed.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><envar>LANG</envar></term>

    <listitem>

    <para>

        The <envar>LANG</envar> environment variable is specific to

        the operating system and controls the default locale

        information of it.  The <command>centos-art.sh</command>

        script use the <envar>LANG</envar> environment variable to

        determine what language to use for printing output messages

        from the script itself, as well as the portable objects

        locations that need to be updated or edited when you localize

        directory structures inside the working copy of &TCAR;.

    </para>

    <para>

        The <envar>LANG</envar> environment variable is initially set

        in the installation process of &TC;;, specifically in the

        <emphasis>Language</emphasis> step.  Generally, there is no

        need to customize this variable in your personal profile. If

        you need to change the value of this environment variable do

        it through the login screen of GNOME Desktop Environment or

        the <command>system-config-language</command> command, or even

        resetting the variable before executing the

        <command>centos-art.sh</command> script.

    </para>

    </listitem>

    </varlistentry>

    </variablelist>

    <para>

        In addition to system environment variables described above,

        the centos-art.sh script adds the following variables inside

        the <filename>~/.bash_profile</filename> file to control the

        script behaviour in a per-user level:

    </para>

    <variablelist>

    <varlistentry>

    <term><varname>TCAR_WORKDIR</varname></term>

    <listitem>

    <para>

        The <envar>TCAR_WORKDIR</envar> environment variable is

        specific to <command>centos-art.sh</command> script and

        controls the working copy default location in the workstation.

        This variable doesn't exist just after installing your

        workstation. In order for this variable to be customizable you

        need to configure your workstation first, as described in

        <xref linkend="repo-ws-config" />.

    </para>

    <para>

        By default, when this variable hadn't been set, the

        centos-art.sh script assumes the 

        class="directory">${HOME}/artwork</filename> path as default

        location for your working copy.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>TCAR_BRAND</varname></term>

    <listitem>

    <para>

        ...   

    </para>

    </listitem>

    </varlistentry>

    </variablelist>

    </sect2>

    <sect2 id="scripts-bash-environment-functions">

    <title>Environment Functions</title>

    <para>

        In addition to environment variables described above, the

        centos-art.sh script makes available the following common

        environment functions:

    </para>

    <variablelist>

    <varlistentry>

    <term><function>cli_checkFiles <parameter>FILE</parameter> <parameter>...</parameter></function></term>

    <listitem>

    <para>

        ...

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><function>cli_printMessage <parameter>MESSAGE</parameter> <parameter>TYPE</parameter></function></term>

    <listitem>

    <para>

        ...

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><function>cli_exportFunctions <parameter>PATH</parameter></function></term>

    <listitem>

    <para>

        ...

    </para>

    </listitem>

    </varlistentry>

    </variablelist>

    </sect2>

</sect1>