Scan and clean

diskdiet has two everyday commands: scan (the default) measures and changes nothing; clean removes what the scan reports as old, after showing the list and asking.

What counts as old

Flag	Meaning
--older-than 30d (default)	Unchanged for this long. Accepts 12h, 7d, 2w…
--all	Everything, whatever its age

"Unchanged" means different things per cache: for npm it's when the entry was written to the cache; for Go's build cache it's the last time Go used it; for node_modules and target folders it's when anything at the top of the project last changed. See What diskdiet cleans.

Choosing sources

Flag
--only npm,docker	Only these sources
--skip node_modules	Everything but these
--projects ~/code	Where to look for node_modules and target folders (repeatable; default: your home folder)
--keep DIR	Leave this node_modules or target folder alone (repeatable)
--trash	Move node_modules and target folders to the Trash (Recycle Bin on Windows) instead of deleting them; see below
--volumes	Also remove unused Docker volumes (they can hold databases)

Source names: npm, yarn, pnpm, bun, pip, uv, cargo, go, gradle, maven, playwright, cypress, xcode, simulators, cocoapods, swiftpm, android, homebrew, docker, node_modules, target.

Confirming

Flag
(none)	Show the list, ask [y/N]
-n, --dry-run	Show the list, remove nothing
-y, --yes	Don't ask (scripts, CI)
--force	Clean even while a package manager is installing

Without a terminal (in a script), clean refuses to run unless you pass --yes or --dry-run.

Undo: move project folders to the Trash

diskdiet clean --only node_modules --trash

node_modules and target folders go to the macOS Trash, the Windows Recycle Bin or the Linux desktop Trash, so you can put any of them back. Their space is freed when you empty the Trash, so on a full disk, clean without --trash. Caches are always deleted: everything in them downloads again anyway.

Safety rules

• What clean removes is exactly what it showed you.
• Every removal is checked to be inside the cache folder it belongs to; symlinks are never followed.
• pnpm, uv and Docker decide what is unused with their own commands (pnpm store prune, uv cache clean, docker … prune).
• If npm install, pnpm add, yarn, cargo build, go test or a Gradle or Maven build is running, that cache is skipped. A long-running npm run dev or an idle Gradle daemon doesn't count.
• Docker volumes stay unless you pass --volumes.

Examples

diskdiet scan --projects ~/code --projects ~/work
diskdiet clean --older-than 2w --skip docker
diskdiet clean --only node_modules --keep ~/code/current-project/node_modules
diskdiet clean --all --only uv --yes

Full reference: diskdiet clean, diskdiet scan.