plutil is very useful command line utility to decode or encode the .plist files if you do not GUI tools like PropertyList Editor or PrefSetter etc.
- Type the following command in terminal to convert the binary1 format of plist fle to xml1 format.
$ sudo plutil -convert xml1 /Library/Preferences/com.my.newplist.plist
- Now Edit the .plist file.
- Type the following command in terminal to convert the xml1 format plist fle back again to binary1 format.