The Execution Environment
The execution environment of centos-art.sh
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 centos-art.sh 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
~/.bash_profile file, as well.
The centos-art.sh script uses the
~/.bash_profile file to implement
per-user customizations. For example, you can use this file
to set the location of your working copy through the
TCAR_WORKDIR enviroment variable. By default
this variable is set to ${HOME}/artwork, but you can
reset to something different to fit your needs. See .
Once the centos-art.sh script has been
executed, it creates different levels of execution
environments inside the one created by the script itself on
the shell. These different environment levels can be seen as
a tree of execution environments which inherit one another, as
illustrated in . These
different levels of execution evironments are where the
centos-art.sh script is developed in.
The execution environment
The execution environment
---------------------------------------------------------------
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() . .
. . `-- ... . .
. ..................................................... .
...............................................................
The first file the centos-art.sh script
calls is the
trunk/Scripts/Bash/Functions/Common/cli.sh
file. This file initializes variables and functions can be
used along the script execution environment lifetime. Such
environment variables are for internal use inside the
centos-art.sh 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 ~/.bash_profile file.
Environment Variables
The centos-art.sh script uses the following
system environment variables:
PATH
The PATH 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 ~/bin directory which is one of
the locations used as search path in this variable. This is
how we create the centos-art command from
the centos-art.sh script inside your
working copy.
This variable is not initialized inside the
centos-art.sh script. Instead, the value
set in ~/.bash_profile file is used.
EDITOR
The EDITOR environment variable is specific to
the operating system and provides the path to your default
text editor. The centos-art.sh script uses
the default text editor to edit subversion pre-commit
messages, translation files, documentation files, script
files, and similar text-based files.
Possible values for this variable are:
/usr/bin/vim
/usr/bin/emacs
/usr/bin/nano
In case none of these values is set for the
EDITOR environment variable inside
~/.bash_profile, the
centos-art.sh script uses /usr/bin/vim as default text
editor. This is the default text editor installed by default
in &TCD;.
TEXTDOMAIN
The TEXTDOMAIN 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 TEXTDOMAINDIR, is
used by gettext to find out the
location of translation messages. In the very specific case
of centos-art.sh script we use the
centos-art.sh name as domain name.
This variable is initialized inside the
centos-art.sh script, so if you set it
outside it (e.g., in ~/.bash_profile) the
value you set there will be overwritten by that one set inside
centos-art.sh script, once it is executed.
TEXTDOMAINDIR
The TEXTDOMAINDIR 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
TEXTDOMAIN environment variable. In the very
specific case of centos-art.sh script we
use the trunk/Locales/Scripts/Bash
path as default value.
This variable is initialized inside the
centos-art.sh script, so if you set it
outside it (e.g., in ~/.bash_profile) the
value you set there will be overwritten by that one set inside
centos-art.sh script, once it is executed.
TMPDIR
The TMPDIR 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
centos-art.sh script itself using the
mktemp command and will be unique on each
script execution. Thus, you should be able to run several
instances of centos-art.sh script
simultaneously without any problem.
Each time you need to store temporal files, do it inside the
absolute path specified by this variable.
This variable is initialized inside the
centos-art.sh script, so if you set it
outside it (e.g., in ~/.bash_profile) the
value you set there will be overwritten by that one set inside
centos-art.sh script, once it is executed.
LANG
The LANG environment variable is specific to
the operating system and controls the default locale
information of it. The centos-art.sh
script use the LANG 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;.
The LANG environment variable is initially set
in the installation process of &TCD;, specifically in the
Language 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 system-config-language command, or even
resetting the variable before executing the
centos-art.sh script.
In addition to system environment variables described above,
the centos-art.sh script adds the following
variables inside the ~/.bash_profile file
to control the script behaviour in a per-user level:
TCAR_WORKDIR
The TCAR_WORKDIR environment variable is
specific to centos-art.sh 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
.
By default, when this variable is not set, the
centos-art.sh script assumes the ${HOME}/artwork path as default
location for your working copy.
TCAR_BRAND
The TCAR_BRAND environment variable is specific
to centos-art.sh script and controls the
brand information that identifies the content produced inside
&TCAR;. The brand information is used to give name to some
files inside the repository (e.g., see files under trunk/Identity/Models/Brands
directory).
By default, this variable takes centos as
value. In case you want to change it to something else, you
should consider the following implications:
The centos-art.sh script will no longer be
referred as such. Instead, the
${TCAR_BRAND}-art.sh name will be used.
This implies that you no longer are using the
centos-art.sh file we provide as part of
&TCAR; and won't be able to commit changes to it. However, if
you retain the same logic from
centos-art.sh script in
${TCAR_WORKDIR}-art.sh, you can use
common and specific functionalities provided by
centos-art.sh script and commit changes to
them.
The files stored under trunk/Identity/Models/Brands
should be named using the value of
${TCAR_BRAND} as sect2. If you change
the value of this variable, you need to be sure the new value
set does coincide with the file names you use to store brand
information.
Environment Functions
Once environment variables are initialized, the
centos-art.sh script initializes common and
specific environment functions.
Common environment functions are stored under trunk/Scripts/Bash/Functions/Commons
directory and will be available always, both for common
environment functions themselves and specific environment
functions.
Specific environment functionalities, on the other hand, are
stored in the trunk/Scripts/Bash/Functions/${CLI_FUNCDIRNAM}/${CLI_FUNCNAME}.sh
file, where CLI_FUNCDIRNAME is the first
argument passed to centos-art.sh script with the first letter
in uppercase but the rest in lowercase and
CLI_FUNCNAME is the first argument passed
to centos-art.sh script with all letters in lowercase.
Specific functionalities are exported after common
functionalities, so specific environment functionalities
aren't available inside common environment functionalities.
In ,
render, help and
locale are all specific environment
functions while cli_printMessage and
cli_getFilesList are common environment
functions.
Both specific and common environment functions exist to
standardize frequent tasks inside &TCAR;. The following
sect2s will describe which these frequent tasks are and the
way they are standardized using specific and common
environment functions.