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LOU_TRACE(1) User Commands LOU_TRACE(1)


lou_trace - A tool to list all the rules that were used for a Braille translation


lou_trace [OPTIONS] TABLE[,TABLE,...]


Examine and debug Braille translation tables. This program allows you to inspect liblouis translation tables by printing out the list of applied translation rules for a given input.
-h, --help
display this help and exit
-v, --version
display version information and exit
-f, --forward
forward translation using the given table
-b, --backward
backward translation using the given table
Use no contractions
Display dot patterns
Use Unicode Braille patterns
Disable output of undefined dot numbers during back-translation
Use partial back-translation If neither -f nor -b are specified forward translation is assumed


Written by Bert Frees.


Report bugs to
Liblouis home page: <>


Copyright © 2019 Swiss Library for the Blind, Visually Impaired and Print Disabled. License GPLv3+: GNU GPL version 3 or later <>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


The full documentation for lou_trace is maintained as a Texinfo manual. If the info and lou_trace programs are properly installed at your site, the command
info liblouis

should give you access to the complete manual.

November 2020 Liblouis 3.16.0