Qt Linguist Manual: Release Manager

lupdate

Usage: lupdate myproject.pro

lupdate is a command line tool that finds the translatable strings in the specified source, header and Qt Designer interface files, and produces or updates .ts translation files. The files to process and the files to update can be set at the command line, or provided in a .pro file specified as an command line argument. The produced translation files are given to the translator who uses Qt Linguist to read the files and insert the translations.

Companies that have their own translators in-house may find it useful to run lupdate regularly, perhaps monthly, as the application develops. This will lead to a fairly low volume of translation work spread evenly over the life of the project and will allow the translators to support a number of projects simultaneously.

Companies that hire in translators as required may prefer to run lupdate only a few times in the application's life cycle, the first time might be just before the first test phase. This will provide the translator with a substantial single block of work and any bugs that the translator detects may easily be included with those found during the initial test phase. The second and any subsequent lupdate runs would probably take place during the final beta phase.

The TS file format is a simple human-readable XML format that can be used with version control systems if required. lupdate can also process Localization Interchange File Format (XLIFF) format files; files in this format typically have file names that end with the .xlf suffix.

Note: The minimum supported version for XLIFF format files is 1.1. XLIFF 1.0 version files are not supported.

Pass the -help option to lupdate to obtain the list of supported options:

 Usage:
     lupdate [options] [project-file]
     lupdate [options] [source-file|path]... -ts ts-files
 Options:
     -help  Display this information and exit.
     -noobsolete
            Drop all obsolete strings.
     -extensions <ext>[,<ext>]...
            Process files with the given extensions only.
            The extension list must be separated with commas, not with whitespace.
            Default: 'ui,c,c++,cc,cpp,cxx,ch,h,h++,hh,hpp,hxx'.
     -pluralonly
            Only include plural form messages.
     -silent
            Do not explain what is being done.
     -version
            Display the version of lupdate and exit.

Qt Linguist is also able to import and export XLIFF files. See the Translators section for more information.

 Usage:
     lrelease [options] project-file
     lrelease [options] ts-files [-qm qm-file]

 lrelease is part of Qt's Linguist tool chain. It can be used as a
 stand-alone tool to convert XML-based translations files in the TS
 format into the 'compiled' QM format used by QTranslator objects.

 Options:
     -help  Display this information and exit
     -idbased
            Use IDs instead of source strings for message keying
     -compress
            Compress the QM files
     -nounfinished
            Do not include unfinished translations
     -removeidentical
            If the translated text is the same as
            the source text, do not include the message
     -markuntranslated <prefix>
            If a message has no real translation, use the source text
            prefixed with the given string instead
     -silent
            Do not explain what is being done
     -version
            Display the version of lrelease and exit