Package Management- Installing/Uninstalling/depends/reverse-depends

**DiagonalArg** · March 5th, 2013

Maybe someone can help me understand a little about package management. Namely, when uninstalling a package how do I know exactly what other pkgs, originally installed as dependencies, I can uninstall? For example:

A -> installs -> B and C; C in turn installs -> D.

At some time later, I install A' which depends on C (and thereby, D).

Now, I want to uninstall A and all packages that were installed as dependencies but are unused by any subsequently installed package (in this case, B). How do I figure this out?

A parallel question is whether I can find a tree not just of all packages and their (reverse)/dependencies, but of the packages that I specifically installed (and their dependencies).

**Cheesemill** · March 5th, 2013

Code:

sudo apt-get autoremove

Will remove any packages on your system that were originally installed as dependencies but are no longer needed.

**cortman** · March 5th, 2013

When you run

Code:

sudo apt-get remove package

it figures out dependencies that would be redundant and removes those as well. If for some reason it misses some (or later package removal makes the dependencies unnecessary) running apt-get autoremove will, as Cheesmill said remove them.

**slickymaster** · March 5th, 2013

All installation operations that happen using apt-get or Ubuntu Software Center are stored in /var/log/apt/history.log. The history.log file contains all the operations performed on your system using apt-get. Specifically a Start-Date and End-Date for the operation, the operation performed and
additional information about the operation.