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

    <title>Execution Environment Reference</title>

    <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    |-- TCAR_BRAND    |-- EDITOR          .

.   |-- LANG            |-- HOME          |-- PATH            .

.   `-- 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/${CLI_FUNCDIRNAM}/${CLI_FUNCNAME}.sh</filename>

        file where <varname>CLI_FUNCDIRNAM</varname> is the function

        name with the first letter in upper case and

        <varname>CLI_FUNCNAME</varname> is the function name with all

        letters in lower case.

    </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

        functionalities.

    </para>

</sect1>