gettext: Preparing Shell Scripts
15.5.12.1 Preparing Shell Scripts for Internationalization
..........................................................
Preparing a shell script for internationalization is conceptually
similar to the steps described in ⇒Sources. The concrete steps
for shell scripts are as follows.
1. Insert the line
. gettext.sh
near the top of the script. ‘gettext.sh’ is a shell function
DONTPRINTYET library that provides the functions ‘eval_gettext’ (see ⇒
eval_gettext Invocation), ‘eval_ngettext’ (see *noteDONTPRINTYET DONTPRINTYET library that provides the functions ‘eval_gettext’ (see ⇒
eval_gettext Invocation), ‘eval_ngettext’ (see ⇒
eval_ngettext Invocation), ‘eval_pgettext’ (see *noteDONTPRINTYET DONTPRINTYET DONTPRINTYET library that provides the functions ‘eval_gettext’ (see ⇒
eval_gettext Invocation), ‘eval_ngettext’ (see ⇒
eval_ngettext Invocation), ‘eval_pgettext’ (see ⇒
eval_pgettext Invocation), and ‘eval_npgettext’ (see *noteDONTPRINTYET DONTPRINTYET DONTPRINTYET library that provides the functions ‘eval_gettext’ (see ⇒
eval_gettext Invocation), ‘eval_ngettext’ (see ⇒
eval_ngettext Invocation), ‘eval_pgettext’ (see ⇒
eval_pgettext Invocation), and ‘eval_npgettext’ (see ⇒
eval_npgettext Invocation). You have to ensure that ‘gettext.sh’
can be found in the ‘PATH’.
2. Set and export the ‘TEXTDOMAIN’ and ‘TEXTDOMAINDIR’ environment
variables. Usually ‘TEXTDOMAIN’ is the package or program name,
and ‘TEXTDOMAINDIR’ is the absolute pathname corresponding to
‘$prefix/share/locale’, where ‘$prefix’ is the installation
location.
TEXTDOMAIN=@PACKAGE@
export TEXTDOMAIN
TEXTDOMAINDIR=@LOCALEDIR@
export TEXTDOMAINDIR
3. Prepare the strings for translation, as described in ⇒
Preparing Strings.
4. Simplify translatable strings so that they don’t contain command
substitution (‘"`...`"’ or ‘"$(...)"’), variable access with
defaulting (like ‘${VARIABLE-DEFAULT}’), access to positional
arguments (like ‘$0’, ‘$1’, ...) or highly volatile shell
variables (like ‘$?’). This can always be done through simple
local code restructuring. For example,
echo "Usage: $0 [OPTION] FILE..."
becomes
program_name=$0
echo "Usage: $program_name [OPTION] FILE..."
Similarly,
echo "Remaining files: `ls | wc -l`"
becomes
filecount="`ls | wc -l`"
echo "Remaining files: $filecount"
5. For each translatable string, change the output command ‘echo’ or
‘$echo’ to ‘gettext’ (if the string contains no references to shell
variables) or to ‘eval_gettext’ (if it refers to shell variables),
followed by a no-argument ‘echo’ command (to account for the
terminating newline). Similarly, for cases with plural handling,
replace a conditional ‘echo’ command with an invocation of
‘ngettext’ or ‘eval_ngettext’, followed by a no-argument ‘echo’
command.
When doing this, you also need to add an extra backslash before the
dollar sign in references to shell variables, so that the
‘eval_gettext’ function receives the translatable string before the
variable values are substituted into it. For example,
echo "Remaining files: $filecount"
becomes
eval_gettext "Remaining files: \$filecount"; echo
If the output command is not ‘echo’, you can make it use ‘echo’
nevertheless, through the use of backquotes. However, note that
inside backquotes, backslashes must be doubled to be effective
(because the backquoting eats one level of backslashes). For
example, assuming that ‘error’ is a shell function that signals an
error,
error "file not found: $filename"
is first transformed into
error "`echo \"file not found: \$filename\"`"
which then becomes
error "`eval_gettext \"file not found: \\\$filename\"`"