Delete a specific key value using the defaults delete command line tool

Question

Having the following .plist file:

/usr/bin/sudo /usr/bin/defaults read /Library/Preferences/com.apple.systempreferences.plist

{
    DisabledPreferencePanes =     (
        "com.apple.preference.general",
        "com.apple.preference.mouse"
    );
}

Using the defaults command line tool, if I want to delete for example only the com.apple.preference.mouse line from the plist how do I do that?

Answer 1

The output of the defaults command, in your OP, shows a single key, DisabledPreferencePanes, as an array with two elements. Unfortunately defaults cannot explicitly delete a single element in an array containing multiple elements, in this case com.apple.preference.mouse.

Since the target com.apple.systempreferences.plist file in /Library/Preferences only has the single key as an array, the entire file and thus the array can be overwritten without the target element in the array, e.g.:

    NOTE: This form of the command overwrites the entire target file.

sudo defaults write /Library/Preferences/com.apple.systempreferences.plist '{ DisabledPreferencePanes = ("com.apple.preference.general"); }'

If the target .plist file had other keys, you could overwrite just the target key, e.g:

    NOTE: This form of the command overwrites just the target array.

sudo defaults write /Library/Preferences/com.apple.systempreferences.plist DisabledPreferencePanes -array com.apple.preference.general

That said, I prefer to use PlistBuddy because a single element of the array can be deleted, e.g.:

sudo /usr/libexec/PlistBuddy -c "Delete :DisabledPreferencePanes:1" /Library/Preferences/com.apple.systempreferences.plist

• In PlistBuddy, array items are specified by a zero-based integer index.

PlistBuddy can also be easier to use in a shell script where one could code it to find a target element of an array and delete it. This could not be done with defaults as it can only write (or overwrite) an array without the target element in it.

---

Notes:

• System Preferences should be closed when modifying its releated .plist files.

• Immediately after modifying the target file, in this use case, you need to terminate all occurrences of cfprefsd.

  • As one is owned by root you'll need to use sudo in Terminal, e.g.:

    sudo killall cfprefsd
    

  • If you do not do this, the edited file may/will be overwriten by its original copy in memory, thus making the changes null and void.

• cfprefsd will reload on its own afterwards.