script macOS preference domain reads/writes with defaults(1) and force cfprefsd to reload its in-memory cache
domain: developer.apple.com · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Read a value with `defaults read <domain> <key>` and write with `defaults write <domain> <key> <type> <value>`, using the reverse-DNS bundle id as the domain.
Target another user's domain non-interactively by pointing at `~/Library/Preferences/<domain>.plist` directly when running as a different UID (e.g., from a root launchd job).
Note that changes may not take effect immediately after writing while the target app is running, because cfprefsd caches values in memory.
Force a fresh read by running `killall cfprefsd`, which flushes pending writes to disk and restarts the daemon so subsequent `defaults read` calls reflect the new value.
Verify the write actually landed by re-reading the key after the cfprefsd restart rather than trusting the write command's exit status alone.
Known gotchas
Writing preferences for an app while it's actively running is often overwritten when the app writes back its own in-memory prefs on quit; quit the target app before scripting bulk preference changes.
`killall cfprefsd` momentarily blocks any process trying to read/write preferences system-wide while it restarts, which can cause races in concurrent automation.
Sandboxed apps store prefs under a container path, so a plain `defaults write com.example.app` may create a plist that the sandboxed app never actually reads.
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