Using lcheck

The lcheck command line tool validates Qt TS translation files and produces a human-readable report. It is part of the Qt Linguist toolchain and is intended for batch or CI usage to catch common localization issues early. By default, lcheck runs a set of checks and returns a non-zero exit code if at least one enabled check fails.

The default checks are:

• Accelerator check — Verifies that the number of ampersands (mnemonics) in source and translation match.
• Surrounding whitespace check — Verifies that leading and trailing whitespace of source and translation match.
• Ending punctuation check — Verifies that source and translation end with the same punctuation.
• Place marker check — Verifies consistent usage of %1, %2, and so on, between source and translation.

Each check can be disabled individually using command line options.

lcheck syntax

lcheck [options] -o report-output-file ts-file
lcheck [options] ts-file

Where:

• options means one or several lcheck options.
• ts-file is the TS file to validate.
• report-output-file is the path of the file to write the report to. If omitted, the report is written to the standard error stream.

To view the latest help, enter:

lcheck -help

lcheck options

Examples

Write a report to a file

lcheck -o lcheck_report.txt translations/myapp_de.ts

Disable selected checks

The following command runs all checks except accelerator and punctuation:

lcheck -no-accelerator -no-punctuation translations/myapp_de.ts

Check finished translations as well

lcheck -check-finished translations/myapp_de.ts

Use lcheck in a CI step

lcheck translations/myapp_de.ts && echo "Translations OK" || echo "Issues found"

Using lcheck with CMake

To call lcheck when configuring or building your CMake project, load the Qt6LinguistTools package and use $<TARGET_FILE:Qt6::lcheck> to locate the lcheck executable.

The following example adds a custom target check_translations that runs lcheck over a TS file and writes a report next to the build artifacts.

find_package(Qt6 REQUIRED COMPONENTS LinguistTools)

add_custom_command(
    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/lcheck_report.txt"
    COMMAND $<TARGET_FILE:Qt6::lcheck>
            -o "${CMAKE_CURRENT_BINARY_DIR}/lcheck_report.txt"
            "${CMAKE_CURRENT_SOURCE_DIR}/translations/myapp_de.ts"
    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/translations/myapp_de.ts"
    VERBATIM
)

add_custom_target(check_translations
    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/lcheck_report.txt"
)

Using lcheck with qmake

You can run lcheck directly on a TS file without specifying a project file:

lcheck translations/myapp_de.ts