Quassel has no way to save its IRC chat logs by default. But Quassel wiki provides a Python program to do this job easily. The program name is dumplog. The dumplog program is free software (GNU GPL). Here some instruction about how to dump (save) Quassel database (chat log) into a text file. Thank you Ramon Klass for creating dumplog.
Obtain the program here: http://bugs.quassel-irc.org/attachments/download/400/dumplog-0.0.1.tar.gz. Extract it to a directory first before you use it.
Save Chat Log
To save (dump) a chat log, use this command:
python dumplog.py -u username -n network -c "channel" -o file-name.logFor example, we can use this command to save our chat log in #ubuntu channel in Freenode network.
python dumplog.py -u AdminUser -n Freenode -c "#ubuntu" -o ubuntu.logFor another example, we can use this comand to save our #gnu channel chat log.
python dumplog.py -u AdminUser -n Freenode -c "#gnu" -o gnu.logThe result of every command is a file with .log extension which is a plain text file. You may only save one channel per one command, you can not save the whole network you use in Quassel (for example, the whole Freenode). And you will need Quassel username: AdminUser, not your Ubuntu system username. You may see this Quassel username by invoking those command without -u option.