11

Am looking to edit system preferences settings via the command line but cannot for the life of me find the correct names of variables.

In Login Options under Users & Groups, I would like to be able to change the Display login window from list of users to 'name and password'.
In Date & Time, I would like to know how I change the time to a server we use. Enable fields in Sharing Setup Energy Saver settings

It would be great if someone can help me out or point me in the right direction as I know you edit the preferences .plists but its knowing what to add or finding the preferred naming conventions.

Thanks.

  • 1
    Did you manage to configure the login options? – user87208 Aug 8 '14 at 20:49
20

First off, you can check out a website that lists a lot of these things: http://secrets.blacktree.com/

I, however, just took a brute-force solution:

Copy the Preferences folder

$ cp -r /Library/Preferences before

Launch System Preferences. Make a change via the GUI. Probably best to do one change at a time, e.g. I changed "Display Login Window as:" from "List of users" to "Name and password". Quit System Preferences.

Copy the Preferences folder again:

$ cp -r /Library/Preferences after

See which files changed:

$ diff -ur before after
Binary files before/Preferences/com.apple.loginwindow.plist and after/Preferences/com.apple.loginwindow.plist differ

Compare the two versions. Since they are binary files, you'll need to convert them to XML for comparison. I use an alias for this:

$ alias plist='plutil -convert xml1 -o /dev/stdout'
$ diff -u <(plist before/Preferences/com.apple.loginwindow.plist) <(plist after/Preferences/com.apple.loginwindow.plist)
--- /dev/fd/63  2013-01-23 18:20:29.000000000 +0200
+++ /dev/fd/62  2013-01-23 18:20:29.000000000 +0200
@@ -9,7 +9,7 @@
    <key>RetriesUntilHint</key>
    <integer>3</integer>
    <key>SHOWFULLNAME</key>
-   <false/>
+   <true/>
    <key>lastUser</key>
    <string>loggedIn</string>
    <key>lastUserName</key>

At this point we have located the setting. Confirm we have it with defaults:

$ defaults read /Library/Preferences/com.apple.loginwindow SHOWFULLNAME
1
$ sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWFULLNAME -bool false
$ defaults read /Library/Preferences/com.apple.loginwindow SHOWFULLNAME
0

Launch System Preferences and confirm it changed.

7

sudo opensnoop -n cfprefsd shows what property lists are being accessed. You can also just sort the preference files by modification date: ls -t {~,}/Library/Preferences/{ByHost,}.

For preferences in the user domain, you can also run defaults read > temp, change some preference, and run diff temp <(defaults read).

  • on macOS 10.12.1, opensnoop just prints error messages; first dtrace: system integrity protection is on, some features will not be available, then a list of messages like dtrace: error on enabled probe ID 5 (ID 167: syscall::open:return): invalid user access in action #11 at DIF offset 2; the second part seems to work well – ssc Dec 8 '16 at 14:49
1

You can use AppleScript to control many of the System Preferences properties. See https://www.macosxautomation.com/applescript/features/system-prefs.html for examples.

Depending on what you want to do, you can create a script to do things like

$ set-setting "dock preferences" "autohide:true, magnification:false"

Use the Script Editor.app to run and debug code in case the property labels have changed in newer macOS versions.

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