On: Maybe: run a command, see what it does to your files without actually doing it

[majke]

Nice idea. Shameless plug: this reminds me a ptrace hack I did a couple years back:

fluxcapacitor

https://github.com/majek/fluxcapacitor#fluxcapacitor

https://idea.popcount.org/2013-07-19-how-to-sleep-a-million-...