Xcode script on build to update version number string in Settings.bundle
You can add a run script phase for your target (build phases > add build phase > add run script). Then you will have a shell script where you could use PlistBuddy to get the version string and set it in your other plist.
For example :
/usr/libexec/PlistBuddy -c "print:CFBundleVersion" "$CONFIGURATION_BUILD_DIR/$INFOPLIST_PATH"
will display the version string of your app. If you record this in a variable and set the value on the other plist using Plist Buddy -c set, you will be done.
This would give something like :
versionString=$(/usr/libexec/PlistBuddy -c "print:CFBundleVersion" "$CONFIGURATION_BUILD_DIR/$INFOPLIST_PATH")/usr/libexec/PlistBuddy -c "Set CURRENT_VERSION_NO $versionString" "$THE_PATH_TO_YOUR_PLIST_FILE"I never used PlistBuddy -c copy but it should allow you to do this in only one line.