Command line and power tools

Searching by ownership

Updated 2026-07-31 · 4 min read

Useful after migrating from another Mac, or when an app cannot write somewhere it should.

By owner

find ~ ! -user "$(whoami)" 2>/dev/null
find /Applications -user root

Files owned by someone else are the usual cause of "you do not have permission" errors after a Migration Assistant transfer, because the old account's numeric user ID may not match the new one.

By permission

find ~ -type f -perm 777          # world-writable, usually wrong
find ~ -type f ! -perm -u+r       # you cannot read your own file
find ~ -type d -perm -o+w         # world-writable directories

Fixing ownership

sudo chown -R "$(whoami)" ~/Documents/ProblemFolder

Be precise about the path. A chown -R at the wrong level, especially with sudo, is one of the more effective ways to break a Mac.

Fixing permissions

chmod -R u+rw ~/Documents/ProblemFolder
find ~/Documents/Folder -type d -exec chmod 755 {} \;
find ~/Documents/Folder -type f -exec chmod 644 {} \;

That last pair is the standard shape: directories need execute to be traversable, files do not.

Extended attributes and quarantine

xattr -l somefile
xattr -d com.apple.quarantine somefile

The quarantine attribute is what triggers "downloaded from the internet" warnings. Removing it is occasionally necessary and should be done knowingly.

Locked files

Finder's Locked checkbox in Get Info maps to a filesystem flag:

chflags nouchg somefile

That is the fix when a file refuses to move or delete despite correct permissions.

Common questions

Why do I get 'permission denied' on my own files after migrating?

The numeric user ID from the old Mac may differ. sudo chown -R $(whoami) on the affected folder fixes it.

What does chflags uchg do?

Sets the immutable flag, which is what Finder's Locked checkbox toggles.