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

    <title>The Command-line Interface</title>

    <para>

        The <command>centos-art.sh</command> script follows a

        conventional command-line interface where there might be

        options and non-option arguments in it. As convention, the

        first non-option argument passed to

        <command>centos-art.sh</command> script will be the name of

        the specific function you want to execute (e.g.,

        <function>render</function>, <function>locale</function>,

        <function>help</function>, etc.).  This first argument will be

        immediately removed from the list of arguments passed to

        <command>centos-art.sh</command> script to leave just the

        remaining options and non-option arguments passed to it.  At

        this point, the <command>centos-art.sh</command> script uses

        the <command>getopt</command> command to retrieve option

        arguments and remove them from the list of arguments passed to

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

    </para>

    <para>

        Once option arguments have been removed from list of arguments

        passed to <command>centos-art.sh</command> script, non option

        arguments are processed then.  Non-option arguments will

        always be paths pointing directories inside your working copy

        of &TCAR;. These paths can be absolute paths or relative paths

        considering the working copy root directory as sect2. For

        example, both the absolute path 

        class="directory">/home/al/Projects/CentOS/artwork/trunk/Identity/Themes/</filename>

        and the relative path 

        class="directory">trunk/Identity/Themes</filename> point to

        the same location.

    </para>

    <para>

        To better understand the <command>centos-art.sh</command>

        command-line interface, let's consider the real command shown

        in <xref linkend="scripts-bash-cliref-cli-example1" /> as

        sect2.  This command shows the entire command as a list of

        space-separated arguments. The value of each argument can be

        reached using special variable names based on the number of

        arguments passed to the command-line.

    </para>

    <example id="scripts-bash-cliref-cli-example1">

    <title>The command-line interface</title>

    <screenshot>

    <screeninfo>The command-line interface</screeninfo>

    <mediaobject>

    <textobject>

<programlisting>

   ${0}  | |${1}| |          ${2}            | |    ${3}   |

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

centos-art render trunk/Identity/Images/Themes --with-brands

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

</programlisting>

    </textobject>

    </mediaobject>

    </screenshot>

    </example>

    <para>

        In <xref linkend="scripts-bash-cliref-cli-example1" />, the

        relation between special variables and arguments has the

        following meaning:

    </para>

    <variablelist>

    <varlistentry>

    <term><varname>${0}</varname></term>

    <listitem>

    <para>

        This variable contains the absolute path to the command

        executed. In case your home directory be 

        class="directory">/home/john</filename> the value of this

        argument will be expanded to

        <filename>/home/john/bin/centos-art</filename> which is a

        symbolic link to the

        <filename>${TCAR_WORKDIR}/trunk/Scripts/Bash/centos-art.sh</filename>

        file.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>${1}</varname></term>

    <listitem>

    <para>

        This variable contains the first non-option argument we use to

        determine the specific function environment we want to execute

        (e.g., <function>render</function> in this case). The position

        of this information in the command-line is relevant to

        <command>centos-art.sh</command> script and must not be

        changed. Possible values to this variable are specified in

        <xref linkend="scripts-bash-cli-specificfuncs" />.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>${2}</varname></term>

    <listitem>

    <para>

        This variable contains a non-option argument referring a path

        information inside the working copy of &TCAR;. The specific

        path information you provide in this variable must be

        recognized by specific function environment provided in

        <varname>${1}</varname> variable. The position of path

        information in the command-line is not relevant to

        <command>centos-art.sh</command> script and can be changed

        whenever it doesn't be interpreted as value to

        <varname>${1}</varname> variable.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><varname>${3}</varname></term>

    <listitem>

    <para>

        This variable contains an option argument. The specific option

        information you provide in this variable must be recognized by

        specific function environment provided in

        <varname>${1}</varname> variable. The position of options in

        the command-line is not relevant to

        <command>centos-art.sh</command> script and can be changed

        whenever it doesn't be interpreted as value to

        <varname>${1}</varname> variable.

    </para>

    </listitem>

    </varlistentry>

    </variablelist>

    <sect2 id="scripts-bash-cli-commonoptions">

    <title>Common Options</title>

    <para>

        As convention, all function specific environments should

        provide support for the following common options: 

    </para>

    <variablelist>

    <varlistentry>

    <term><option>-h</option> | <option>--help</option></term>

    <listitem>

    <para>

        This option makes <command>centos-art.sh</command> script to

        shows information about the specific function environment

        (e.g., how to execute it, available options, etc.) set as

        first non-option argument. For example, if you provide the

        <command>centos-art render --help</command>, the

        <command>centos-art.sh</command> script will display to you

        the information related to the 

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

        directory.

    </para>

    <para>

        This information is retrived from <quote>The CentOS Artwork

        Repository File System (tcar-fs)</quote> documentation manual.

        This manual is written in Texinfo format and provides a quick

        way for you to read and browse documentation related to each

        directory inside &TCAR; as you work with it from a text

        terminal.

    </para>

    </listitem>

    </varlistentry>

    <varlistentry>

    <term><option>-q</option> | <option>--quiet</option></term>

    <listitem>

    <para>

        This option makes the <command>centos-art.sh</command> script

        to suppress messages sent to standard output. This option

        doesn't suppress error messages, nor questions related to

        script execution.

    </para>

    </listitem>

    </varlistentry>

    </variablelist>

    </sect2>

    <sect2 id="scripts-bash-cli-specificoptions">

    <title>Specific Options</title>

    <para>

        The specific options used by specific and common function

        environments are described in their respective sect2s. See

        <xref linkend="scripts-bash-cli-specificfuncs" /> and 

        linkend="scripts-bash-cli-commonfuncs" /> to know which these

        sect2s are.

    </para>

    <title>Specific Function Environments</title>

    <tgroup cols="2" align="left">

        <row>

            <entry>Name</entry>

            <entry>Description</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-prepare" /></entry>

            <entry>Standardize configuration tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-render" /></entry>

            <entry>Standardize rendition tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-locale" /></entry>

            <entry>Standardize localization tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-help" /></entry>

            <entry>Standardize documentation tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-pack" /></entry>

            <entry>Standardize packing tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-tuneup" /></entry>

            <entry>Standardize maintainance tasks inside &TCAR;</entry>

        </row>

        <row>

            <entry><xref linkend="scripts-bash-svn" /></entry>

            <entry>Standardize version control tasks inside &TCAR;</entry>

        </row>

    </tgroup>

    <title>Common Function Environments</title>

    <tgroup cols="2" align="left">

        <row>

            <entry>Name</entry>

            <entry>Description</entry>

        </row>

        <row>

            <entry><literal>cli_checkFiles</literal></entry>

            <entry>...</entry>

        </row>

    </tgroup>

    </sect2>

    <sect2 id="scripts-bash-cliref-implementation">

        <title>Implementation</title>

        <para>

            When a new function is created to

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

            to consider whether it will use arguments or not. When the

            function doesn't need arguments (e.g., it exists to

            redefine values related to global variables only) there is

            no need to consider a parsing feature for it.  However,

            when the function does use arguments it is very important

            to parse them appropriately (e.g., by using a parsing feature like

            that provided by <command>getopt</command> command).

        </para>

        <para>

            In this sect2 will describe how to parse arguments (both

            option and non-option) inside the

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

            must be used as sect2 whenever you need to create a

            new function for <command>centos-art.sh</command> script.

        </para>

    </sect2>

</sect1>