I want to know about the recent changes that happen on Ubuntu12.04 LTS. In other words, I want to keep tracking all Ubuntu Desktop's standard packages on my eye. But is there any automated method instead of One-by-One method? Standard tool or self-making script will be welcome. Will anyone do me a favor?
If you want a list of all the packages for which updates are available, it can be done using Synaptic Package Manager. It can be installed from Ubuntu Software Center.
After you install Synaptic, open it and click "Reload". It will check for the updates available (an internet connection is needed for this) and load them.
Once the reload completes, click "Mark all upgrades". It'll mark all the packages for which updates are available. To view only the upgrades available, click the button "Custom Filters" available at the bottom-left corner and select "Upgradable (upstream)" in the list available in the left pane.
To save the list of the marked packages to a file, click File > Save Markings As, enter a file name and click "Save".
Hope that answers your question.