prune-xcode

name

prune-xcode

description

Reclaim Xcode and iOS-simulator disk space safely. Measures usage first, then clears the big recoverable caches (global DerivedData, per-worktree .derivedData while skipping any active build, module caches, old iOS DeviceSupport) and offers simulator cleanup (unavailable + duplicate + orphaned custom sims). Shows before/after free space; confirms destructive simulator/Archive deletions. Use when the user asks to free disk, prune DerivedData, clean Xcode/simulator storage, or "my disk is full".

prune-xcode

Reclaim disk from Xcode / iOS build artifacts. Everything here EXCEPT simulator and Archive deletion is recoverable cache (it rebuilds), so the cache steps are safe to run unattended. Simulator/Archive deletion needs explicit confirmation (sims hold test state; Archives are submitted-build dSYMs/IPAs that don't rebuild).

0. Measure first (always)

Show the user where the space is BEFORE deleting anything:

df -h /System/Volumes/Data | tail -1
du -sh ~/Library/Developer/Xcode/DerivedData 2>/dev/null
du -sh ~/Library/Developer/Xcode/iOS\ DeviceSupport 2>/dev/null
du -sh ~/Library/Developer/CoreSimulator/Devices 2>/dev/null
du -sh ~/Library/Developer/Xcode/Archives 2>/dev/null
du -sh ~/Library/Caches/com.apple.dt.Xcode 2>/dev/null
# per-worktree caches (repos that build with -derivedDataPath .derivedData):
find ~/dev -maxdepth 4 -name .derivedData -type d -exec du -sh {} \; 2>/dev/null

Present a table + the total reclaimable, then act.

1. DerivedData -- the usual monster (safe, recoverable)

Global DerivedData lives at ~/Library/Developer/Xcode/DerivedData. It is pure build cache; Xcode rebuilds it on the next build. It is routinely 100s of GB.

• It has 100k+ files, so deleting it is SLOW -- ALWAYS run the delete in the background (run_in_background: true) or it times out and gets killed mid-sweep, leaving "Directory not empty" residue:

  rm -rf ~/Library/Developer/Xcode/DerivedData
  

• For a clean sweep the user should QUIT Xcode first -- an open Xcode keeps writing to DerivedData (you'll see "Directory not empty" if it recreates files mid-delete). If Xcode must stay open, just re-run the rm afterward; residual is harmless.

Per-worktree .derivedData

Some repos build with -derivedDataPath .derivedData (a local cache per worktree). Delete the inactive ones, but SKIP any worktree with an active build:

pgrep -fl xcodebuild   # is a build running, and which derivedDataPath?

Skip the .derivedData of any path an active xcodebuild is using (or whose .derivedData was modified in the last few minutes). Delete the rest in the background:

rm -rf <worktree>/.derivedData

2. iOS DeviceSupport -- recoverable (re-extracted on device connect)

~/Library/Developer/Xcode/iOS DeviceSupport/ holds per-iOS-version debug symbols for physical devices (several GB each). Keep the latest 1-2 OS versions, delete older:

ls -1 ~/Library/Developer/Xcode/iOS\ DeviceSupport/
rm -rf ~/Library/Developer/Xcode/iOS\ DeviceSupport/<old-version>

Reconnecting a device on a deleted version re-extracts it (slow but automatic). If unsure which to keep, ask.

3. Simulators -- CONFIRM before deleting (may hold test state)

xcrun simctl shutdown all 2>/dev/null
xcrun simctl delete unavailable        # safe: removes sims whose runtime you no longer have

For duplicate models / orphaned custom (per-task) sims:

• List: xcrun simctl list devices
• Identify duplicate models (keep one of each) + orphaned custom sims named after dead branches/tasks.
• CONFIRM the deletion list with the user, then delete each: xcrun simctl delete <udid>
• To reclaim a sim's DATA without deleting the device: xcrun simctl erase <udid>

4. Other caches (optional, smaller)

rm -rf ~/Library/Caches/com.apple.dt.Xcode      # safe

Do NOT delete ~/Library/Developer/Xcode/Archives unless the user confirms -- those are submitted-build artifacts, not recoverable.

5. Report

Show df -h /System/Volumes/Data before vs after and the GB reclaimed.

Safety rules

• Delete CACHE / build output only -- never source, worktrees, or Archives (without confirmation).
• Skip the .derivedData of any worktree with an active/in-flight build.
• Large deletes (DerivedData) MUST run in the background to avoid timeouts.
• Confirm before deleting simulators or DeviceSupport versions.