dux
Download

du, extended.

You know du -sh. dux does the next part: it knows which of those gigabytes are caches that rebuild, which are clones, and which you actually need.

Download free Free. Tool commands and the dux command need the direct download.
~ % du -sh ~/Library/Developer/* | sort -h | tail -3
 14G  CoreSimulator
 22G  Xcode/Archives
 64G  Xcode

# what dux tells you about the same folders
DerivedData    31.4 GB   rebuilds on its own     safe
Old archives    6.8 GB   before Oct 2025         review
Simulators     14.6 GB   all devices, command    review
Clones          1.3 GB   shared, frees nothing   not listed

The gigabytes your tools leave behind.

Each one explained: what it is, whether it rebuilds, and what happens if it goes.

The rule catalog grows with every release. Build folders of idle projects are suggested for the Trash; Docker is shown with its size and left to you. Tool commands such as simctl and brew run only in the direct download.

Sizes that survive APFS.

Clones count once

APFS clones share blocks until one copy changes. dux reports the private size, so a 4 GB clone that frees 120 MB says 120 MB.

Hard links explained

Several names, one copy of the data. Deleting one name frees nothing, and dux says so instead of promising space.

Cloud placeholders

Online only files take no local space. They never inflate the map, and they are never counted as reclaimable.

Packages stay whole

.app bundles and libraries show as one item, with their contents available when you ask.

Scriptable, headless, honest exit codes.

The dux command comes with the direct download; install it from Settings in the app. Text output is free; JSON, CSV and cleanup policies are part of Pro, and fleet reporting is part of Business. JSON output carries a schema version.

  • $ dux suggest ~ --top 25 Ranked cleanups with their safety level and the bytes they free. Changes nothing. Free
  • $ dux scan ~ --json Largest folders and totals as JSON. Add --csv for a spreadsheet. Pro
  • $ dux clean --policy team.json --dry-run Applies a cleanup policy and shows what it would do, without acting. Pro
  • $ dux report --json Volume, free, purgeable, reclaimable by category, largest folders, cloud locations. Business
  • $ dux report --extension-attribute free-bytes Prints a Jamf extension attribute; also works as an Intune custom attribute. Business
  • 0success
  • 1error
  • 2usage
  • 3blocked by policy
  • 4not in your plan
  • 130interrupted

A cleanup policy is a small JSON file.

Files go to the Trash or become APFS clones. Without --dry-run dux asks for confirmation on a terminal, and refuses to change anything unattended unless you pass --yes. Every action is logged in Activity, where Undo works while the items are still in the Trash. An administrator profile with ReportOnly makes clean exit with code 3.

maxSafety is safe, review or risky. Rule IDs are in the Rule column of dux suggest.

{
  "schemaVersion": 1,
  "rules": ["xcode.derived-data", "npm.cache"],
  "maxSafety": "safe",
  "roots": ["~"],
  "minimumBytes": 104857600
}

Never runs a command you haven't read.

When a system tool cleans up better than moving files, dux shows the exact command, says whether it can be undone, and waits for you. Commands run only in the direct download, never in the sandboxed App Store build.

How review works
Review sheet showing the command xcrun simctl delete unavailable