defaults cmd and nested dictionaries

Appleski · 11-30-2005, 10:24 AM

How can I change value of a key in nested dictionary using defaults cmd?
I tried something like:

Code:

defaults write com.mypfile Dict_1 -dict Dict_2 -dict myKey myVal

but I get:
Cannot nest composite types (arrays and dictionaries); exiting

For example, I want to edit Change key in com.apple.desktop.plist, which is in default Dictionary of Background Dictionary.

giskard22 · 11-30-2005, 12:36 PM

Not that this is really helpful, but in my experience -- and in what I've read online -- the defaults command is fairly useless when attempting to edit keys that are nested more than one level. You may need to try parsing the XML directly.

bramley · 11-30-2005, 12:38 PM

There is quite a lot that can't be done with defaults easily or at all - and dealing with nested objects is certainly not its strong point.

It might be possible to get what you want by reading the top-level dictionary - to use your example:

Code:

defaults read com.apple.desktop Background

will give a text string that represents all the contents of the dictionary.

Then you would need to do a bit of text manipulation to substitute your value for the relevant key, and write it back to the plist i.e

Code:

defaults write com.apple.desktop Background 'altered text goes here'

There is an example in 'man defaults' although much simpler than you would need to implement. It is possible that such an attempt is too complicated for defaults. 'man defaults' does warn users that not all things are possible with the command.

You might want to look at Applescript, which has a plist manipulator (on Tiger) in the 'System Events' dictionary. I have not tried to use this so am unable to advise further.

Appleski · 12-01-2005, 11:11 AM

Thanks,
I wanted to make things simple.
read/edit/write method works, but when plist is large it's very difficult, escpecially when you are trying to write universal cmd for others to use.

I guess Property List Editor is the tool to use.

11-30-2005, 10:24 AM	#1
Appleski Prospect Join Date: Nov 2005 Posts: 2	How can I change value of a key in nested dictionary using defaults cmd? I tried something like: Code: defaults write com.mypfile Dict_1 -dict Dict_2 -dict myKey myVal but I get: Cannot nest composite types (arrays and dictionaries); exiting For example, I want to edit Change key in com.apple.desktop.plist, which is in default Dictionary of Background Dictionary.

11-30-2005, 12:38 PM	#3
bramley MVP Join Date: Apr 2004 Location: Cumbria, UK Posts: 2,461	There is quite a lot that can't be done with defaults easily or at all - and dealing with nested objects is certainly not its strong point. It might be possible to get what you want by reading the top-level dictionary - to use your example: Code: defaults read com.apple.desktop Background will give a text string that represents all the contents of the dictionary. Then you would need to do a bit of text manipulation to substitute your value for the relevant key, and write it back to the plist i.e Code: defaults write com.apple.desktop Background 'altered text goes here' There is an example in 'man defaults' although much simpler than you would need to implement. It is possible that such an attempt is too complicated for defaults. 'man defaults' does warn users that not all things are possible with the command. You might want to look at Applescript, which has a plist manipulator (on Tiger) in the 'System Events' dictionary. I have not tried to use this so am unable to advise further.

11-30-2005, 12:36 PM	#2
giskard22 Moderator Join Date: May 2003 Posts: 4,272	Not that this is really helpful, but in my experience -- and in what I've read online -- the defaults command is fairly useless when attempting to edit keys that are nested more than one level. You may need to try parsing the XML directly.

12-01-2005, 11:11 AM	#4
Appleski Prospect Join Date: Nov 2005 Posts: 2	Thanks, I wanted to make things simple. read/edit/write method works, but when plist is large it's very difficult, escpecially when you are trying to write universal cmd for others to use. I guess Property List Editor is the tool to use.