INTERNATIONALIZATION AND LOCALIZATION OF SHELL SCRIPTS

2. Processes diagrams
---------------------

Let's assume that a given software comprises a set of shell scripts that
we want to internationalize and localize.

The following diagrams give an overview of each of the involved processes:
internationalization, localization, usage and maintenance.

These diagrams are hybrid, i.e. they exhibit data as well as actions.

Among these actions are execution of some programs of the gettext suite:
gettetxt: marks strings to be insternationalized, then displays localized
          messages during scripts' execution
xgettext: extracts marked strings from a set of shell scripts to build a
          POT or a PO file
msgcmp:   checks a PO file against another PO or a POT file for
          consistency
msginit:  write a PO file using a POT file as its input   
msgfmt:   format a MO file using a POI file as its input
msgmerge: merge or update PO or POT files

(1) Internationalization 

   Set of shell scripts ───> Preparation ───> Marked shell scripts ───╮
                                                                      │
            ╭──────────────<── software.pot <─── xgettext <───────────╯
            │
            ├────> (2) Localization
            │
            ╰────> (4) Maintenance


(2) Localization (example for French and Dutch languages).

       ╭──────────────<── software.pot <── (1) Internationalization
       │
       │
 fr_FR ├──> msginit ──> fr_FR.po ──> PO editor ──> fr_FR.po ──> msgcmp ──╮
       │                                                                 │
       │ ╭─ installation <── fr_FR.mo <── msgfmt <─┬─ fr_FR.po checked <─╯
       │ │                                         │
       │ │                                         ╰────> (4) Maintenance
       │ │
       │ ╰──> /usr/share/locale/fr_FR/LC_MESSAGES/software.mo ─> (3) Usage
       │
 nl_NL ╰──> msginit ──> nl_NL.po ──> PO editor ──> nl_NL.po ──> msgcmp ──╮
                                                                         │
      ╭─ installation <── nl_NL.mo <── msgfmt <──┬── nl_NL.po checked <──╯
      │                                          │
      │                                          ╰────> (4) Maintenance
      │
      ╰───> /usr/share/locale/nl_NL/LC_MESSAGES/software.mo ───> (3) Usage



(3) Usage

   Let's assume that one of the scripts, "myscript.sh" includes following
   command:

   gettext "Good morning"

   and that "Good morning" is translated as follows in the message catalogs:
   /usr/share/locale/fr_FR/LC_MESSAGES/PACKAGE.mo ─> "Bonjour"
   /usr/share/locale/nl_NL/LC_MESSAGES/PACKAGE.mo ─> "Goedemorgen"

           ╭──────────────<── (2) Localization
           │
   LANG=fr ├───> sh myscript.sh or ./myscript.sh ───> "Bonjour"
           │
   LANG=nl ╰───> sh myscript.sh or ./myscript.sh ───> "Goedemorgen"
           


(4) Maintenance

   The maintenance process can be triggered by a script's creation,
   modification or deletion. In the diagram below, the part of the process
   beginning with the msmerge command should be repeated for each available
   PO file. It is therefore advisable to keep an up to date list of
   available translations, especially if there are many.

     Shell scripts updated and marked ───> xgettext ───> software.pot ──╮
                                                                        │
                                (1) Localization ──> <locale>.po ───>┬<─╯
                                                                     │
 ╭─ msgcmp <── <locale>.po <─ PO editor <── <locale>.po <─ msmerge <─╯
 │
 ╰──> <locale>.po checked ─> msgfmt ─> <locale>.mo ─> installation  ────╮
                                                                        │
                 /usr/share/locale/<locale>/LC_MESSAGES/software.mo <───╯
                     
                            
   The maintenance process can be triggered as well by a modification of
   a language catalog for a specific language (to correct an error for
   instance). This variant of the process is shorter:
   
 ╭─ msgcmp <── <locale>.po <── PO editor <── <locale>.po <── Update needed
 │
 ╰─> <locale>.po checked ──> msgfmt ──> <locale>.mo ──> installation  ──╮
                                                                        │
                  /usr/share/locale/<locale>/LC_MESSAGES/software.mo <──╯


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