<sect1 id="scripts-bash-environment"> <title>Environment Variables</title> <para> When you login in your computer you enter into a unique user environment which you can customize by setting environment variables in the <filename>~/.bash_profile</filename> file.<footnote><para>To know more about environment variables, see the bash(1) man page.</para></footnote> This way different users can benefit from their own environment variables to customize the execution of <command>centos-art.sh</command> script in a safe way. For example, users can use the variables of their environments to set different locations for their working copies of &TCAR;.<footnote><para>See <xref linkend="repo-ws-config-ChangeWorkingCopy" /></para></footnote> </para> <para> When you execute the <command>centos-art.sh</command> script, you create a new environment inside the user environment which we call the <command>centos-art.sh</command> script environment. This environment inherits all variables from the user environment and contains the variables and functionalities defined by the <command>centos-art.sh</command> script. If your only interest is using the <command>centos-art.sh</command> script to accomplish tasks inside the working copy, you don't need to know the whole environment of <command>centos-art.sh</command> script but the user environment only. However, if your interest is improving the <command>centos-art.sh</command> script somehow, to know the <command>centos-art.sh</command> script environment is a fundamental knowledge you need to have in order to understand where to put the code you want to contribute inside the script. </para> <example id="scripts-bash-environment-1"> <title>The <command>centos-art.sh</command> script environment</title> <screenshot> <screeninfo>The <command>centos-art.sh</command> script environment</screeninfo> <mediaobject> <textobject> <programlisting> --------------------------------------------------- User environment ----|-------------------|-------------------------- . |-- TCAR_WORKDIR |-- EDITOR . . |-- LANG |-- HOME . . `-- centos-art.sh `-- ... . . ----|------------------------------------ . . centos-art.sh environment . . ----|-----------------|------------------ . . . |-- CLI_NAME |-- render() . . . . |-- CLI_BASEDIR | |-- svg() . . . . |-- CLI_TEMPDIR | `-- docbook() . . . . |-- CLI_VERSION |-- help() . . . . `-- ... `-- ... . . . ......................................... . ................................................... </programlisting> </textobject> </mediaobject> </screenshot> </example> <para> To study the environment of <command>centos-art.sh</command> script consider the directory structure under <filename class="directory">trunk/Scripts/Bash/</filename>. In this structure each directory under <filename class="directory">Functions</filename> creates a new function environment inside the <command>centos-art.sh</command> script environment. You can only execute one function by script execution so it will only be one function environment inside the <command>centos-art.sh</command> script environment every time it is executed. In some cases, it is possible to find a sub-function environment which takes place inside the function environment. This is the case of the <function>render</function> functionality which produces both images and docbook manuals. Likewise function environments to <command>centos-art.sh</command> script environment, there can only exist one sub-function environment inside the current function environment. </para> <note> <para> If you need more environment levels from sub-function environment on, then it is a good time for you to consider the creation of a new function environment at all. </para> </note> <sect2> <title>User's Profile (<filename>~/.bash_profile</filename>)</title> <sect3> <title>Default working copy</title> <screen>TCAR_WORKDIR=${HOME}/artwork</screen> <para> The <envar>TCAR_WORKDIR</envar> environment variable is specific to <command>centos-art.sh</command> script and controls the working copy default location in the workstation. This variable doesn't exist just after installing your workstation. This variable appears inside the <filename>~/.bash_profile</filename> file (and so in the user environment of yours) after configuring your workstation, as described in <xref linkend="repo-ws-config" />. </para> </sect3> <sect3> <title>Default execution path</title> <screen>PATH=$PATH:$HOME/bin</screen> <para> This is the location where we store links to executable files inside the working copy. </para> </sect3> <sect3> <title>Default text editor</title> <screen>EDITOR=/usr/bin/vim</screen> <para> The default text editor information is controlled by the <envar>EDITOR</envar> environment variable. 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> If <envar>EDITOR</envar> environment variable is not set, <command>centos-art.sh</command> script uses <filename class="directory">/usr/bin/vim</filename> as default text editor. Otherwise, the following values are recognized by <command>centos-art.sh</command> script: <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> <para> If none of these values is set in the <envar>EDITOR</envar> environment variable, the <command>centos-art.sh</command> script uses <filename class="directory">/usr/bin/vim</filename> text editor, the one installed by default in &TCD;. </para> </sect3> <sect3> <title>Default locale information</title> <para> The default locale information is controlled by the <envar>LANG</envar> environment variable. This variable is initially set in the installation process of &TCD;, 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. </para> <para> The <command>centos-art.sh</command> script uses 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> </sect3> <sect3> <title>Default time zone representation</title> <para> The time zone representation is a time correction applied to the system time (stored in the BIOS clock) based on your country location. This correction is specially useful to distributed computers around the world that work together and need to be syncronized in time to know when things happened. </para> <para> &TCAR; is made of one server and several workstations spread around the world. In order for all these workstations to know when changes in the server took place, it is required that they all set their system clocks to use the same time information (e.g., through UTC (Coordinated Universal Time)) and set the time correction for their specific countries in the operating system. Otherwise, it would be difficult to know when something exactly happened. </para> <para> Generally, setting the time zone information is a straight-forward task and configuration tools provided by &TCD; do cover time correction for most of the countries around the world, thus we don't include it to your personal profile. </para> <para> In case you need a time precision not provided by any of the date and time configuration tools provided by &TCD; then, you need to customize the <envar>TZ</envar> environment variable in your personal profile to correct the time information by yourself. The format of <envar>TZ</envar> environment variable is described in <code>tzset(3)</code> manual page. </para> </sect3> </sect2> </sect1>