Yep, that's basically the solution that I came up with, too. I have a "dry-run?" flag planned, if I ever end up with enough writeback operations where it'd be

Yep, that's basically the solution that I came up with, too. I have a "dry-run?" flag planned, if I ever end up with enough writeback operations where it'd be useful. (That's the common Unix shell name for it, though it's not entirely consistent -- which is another problem with using Unix built-ins!) One thing I've noticed is that it's really frustrating (and not at all helpful) to require perfect validity from a shell-like tool. There's just too many times where you want to edit something into something else, without needing to find a perfect path of valid and meaningful syntax at every intermediate step. So if you have a flag on an operation that doesn't understand that flag, the flag will have a (?) badge to indicate that it won't be understood or used, but the pipeline will still run.