How do I list uninstalled but recommended packages?

How do I list the packages that are recommended by my current set of installed packages, but for whatever reason weren't installed?

This can sometimes happen if a package B is installed as a recommendation when you install package A; package B's own recommends typically do not get installed.

1. Listing uninstalled Recommends from the terminal:

• Use aptitude

• Click on the Views menu, and on Audit Recommendations (alternately, Ctrl+T to show the menu, arrow keys to go to Views and press R):

  

• This shows you a list of uninstalled recommended packages, and the "parent" package recommending them.

  

2. Listing uninstalled Recommends and Suggests from Synaptic:

• If you have a desktop (or via X-forwarding), use Synaptic

• Click on Custom Filters in the bottom-left, and then on the Missing Recommends filter in the top-left sidebar:

  

• Notice that unlike aptitude, Synaptic also shows "suggested" (or optional) packages such as iproute-doc

For a command-line list, From:

https://serverfault.com/questions/340075/aptitude-list-all-previous-recommended-packages

aptitude search '~RBrecommends:~i'

To complete your original question:

aptitude search '~RBrecommends:~i' | awk '/^p/ {print $2}'