New PlistBuddy Behaviour

So, the new UniBody MacBooks come with a build 9G2133 of 10.5.6, currently build 9G55 of 10.5.6 is what’s out there. What’s more /usr/libexec/PlistBuddy has been updated as well

9G2133 (new):
-rwxr-xr-x 1 root wheel 84400 Sep 24 17:21 PlistBuddy

9G55 (old):
-rwxr-xr-x 1 root wheel 73792 Apr 7 2008 PlistBuddy

What’s changed with PlistBuddy is this:
* Now, exits with non-zero status on failure (like the man page says)
* Writes errors to stderr instead of stdout

What this might mean to you is if you have a script that tests the stdout of PlistBuddy to detect errors, instead of the exit code (which hasn’t worked until now) then that script might just keep going and going and going…

For example: I use  PlistBuddy to add icons to the Dock in custom pkgs I make for work. So the other day when I ran the base packages, Adobe Acrobat being one of them, it just kept going, never fininshing, looking in install.log I found my script stuck in a loop, counting ever higher…

Mar 23 12:42:45 BlankMacBookUni runner[641]: postflight[648]: Print: Entry, "persistent-apps:546217:tile-data:file-label", Does Not Exist

In about 30 mins it had gotten up to 546,217 attempts to read the Dock plist (thas’ a big log file!). Since my script was testing the stdout string which was now blank because it was going to stderr, it didn’t know it reached the end!

To illustrate how I changed the code to compensate for either version, here’s the snippet that will detect if it is at the end of the plist, based on the output (or lack thereof):

Old code:
if [[ "$output" == *Does\ Not\ Exist ]]; then

New Code:
if [[ "$output" == *Does\ Not\ Exist ]] || [ -z "$output" ]; then

So, we’ll see if this is rolled into 10.5.7, probably. For Tiger, I use the PlistBuddy found in /Library/Receipts/iTunesX.pkg/Contents/Resources/, as of iTunes 8.1 it is still the older version.

Hope this of use to someone. Thanks for reading.