This document seeks to serve as a central repository for information regarding debugging, i.e. to see what's going on under the hood of various programs.
There's a log file at $HOME/.config/lxqt/debug.log that will populate with information using [QLoggingCategory](https://doc.qt.io/qt-5/qloggingcategory.html).
There's a few ways to turn this logging on, but the easiest way is to add the following before exec lxqt-session in /usr/bin/startlxqt:
which turns off all debugging except for those messages with the lxqt-session category.
The log level can be controlled from command line options. The following will print all types of messages to /var/log/syslog:
lxqt-globalkeysd --use-syslog --log-level=debug
You can choose different levels (see lxqt-globalkeysd --help) and you can eschew the syslog switch and debug information will be printed to stderr.
At time of writing, other LXQt applications use [qDebug](https://doc.qt.io/qt-5/qdebug.html), which just prints to stderr. Running with 2>/path/to/some/file will get that output. Since startlxqt runs all the applications in /etc/xdg/autostart, any of these files can be edited so that their Exec key includes this addition.
See also /var/log/installer/debug which is created by our [calamares-logs-helper script](https://phab.lubuntu.me/source/calamares-settings-ubuntu/browse/master/lubuntu/calamares-logs-helper) upon a successful install.
To start Calamares in debug mode sudo calamares -d. Debug mode will give information regarding the modules that are loaded and the associated settings.