I also suspect that we’re going to want some kind of function for “I’m just invoking a process with some args, make it all for me”, because needing to define: class Concatted class ShellCat class CatExecutionRequest def cat_files_process_request_input_snapshot def cat_files_process_result_concatted def create_cat_stdout_rules just to write the semantic equivalent of bash’s

output="$(cat "${input_files[@]}")"
exit_code=$?

or python’s

subprocess.check_output(["cat"] + input_files)

doesn’t feel great ergonomically… (But this is how we work that out 🙂)