How does aptitude in Debian 9 allow fine-grained purging of the new package list?

Question

I was curious to note Stephen's assertion in Is there a way to list packages from date when they entered Debian archive? that:

In Debian 9, aptitude allows finer-grained purging of the new packages list, which helps make it manageable and useful.

Could somebody elaborate on this? I did look at the updated manpage of aptitude and while it has much more content than before, couldn't find what Stephen shared the other day. If possible, please somebody share with example/s to see how the new aptitude works with respect to new package lists.

Answer 1

Since version 0.8.2-1, aptitude allows the user to specify which packages should be forgotten from the “new packages” list, using either the forget-new command-line option or the F key in the TUI. Packages can be specified by name, by pattern, by section, or using any of aptitude search patterns; for example

aptitude forget-new '~sdebug' '~slibs'

forgets all new packages in the “debug” and “libs” sections. (I run that automatically after index updates — I don’t care about new packages appearing in those sections.)

This is documented briefly in the manpage:

forget-new

Forgets all internal information about what packages are “new” (equivalent to pressing “f” when in visual mode).

This command accepts package names or patterns as arguments. If the string contains a tilde character (“~”) or a question mark (“?”), it will be treated as a search pattern and every package matching the pattern will be considered (see the section “Search Patterns” in the aptitude reference manual).

The feature was requested in #421043.