# doover reversibility registry — shell constructs (data: CC0-1.0)
rules:
- id: shell.redirect-truncate
match:
effect: destructive
scope:
undo: snapshot-restore
notes: "Truncates before the command runs; `sort f > f` empties f. Top real-world data-loss vector."
- id: shell.redirect-append
match:
effect: mutating
undo: none
notes: "Additive; original bytes remain."