The riot command line does not have an option to specify the output file to write to, forcing users to use shell redirections, e.g.
This comes up as an issue for the Docker image https://hub.docker.com/r/stain/jena/ - as you can't (easily) do > file.txt as arguments to docker run to do redirections within the Docker container.
Lacking an output file parameter also makes it harder to call riot from other programming languages, e.g. called from a Python script.
The problem is that the --output parameter (and --out) is already used to specify the output FORMAT rather than the output FILE. Perhaps --to-file ?