To attach output files via the command line we could start the program as follows:
bd [o1=file1] [o2=file2] ...
There are 4 output channels, o1 ...o4, which can be associated with an external file in this way. The CHANNEL: command can also be used to associate output files with [B/D] channels. All output (standard output, a log of the current session if required, and a history of the screen input if required) is output to files in the current directory. The program will overwrite pre-existing output files, and otherwise create them.