This is a little tricky to configure the log file of bitshares.

Define a file appender

Comment out following lines to tell the log file.

[log.file_appender.default]
filename=logs/default.log

The file "logs/default.log" is the relative path to the data path, which you specify in the witness_node command line.

For example, the command line option is --data-dir data/yw-blockprod, then the log file is in data/yw-blockprod directory.

Append log to the file appender

logger.default is the default logger.

If we want to print log in a log file, we need to add a file appender to the default logger.

[logger.default]
level=info
appenders=stderr,default

Then we could see the logs in the file logs/default.log.

Done~