Undo apt-get build-dep

When you want to compile something from source in Ubuntu/Debian, the easiest way to install the dependencies required to compile it is to run apt-get build-dep PACKAGE. Unfortunately, there is no built-in command to remove these dependencies. Thankfully, a discussion on Launchpad gives a good solution to this problem. Using this, you can “undo” an apt-get build-dep by running a single command. Note that this requires aptitude, so if you’re running Ubuntu 10.10, or you’ve removed aptitude, you’ll first need to install it using the following:

sudo apt-get install aptitude

Now, undo the apt-get build-dep:

sudo aptitude markauto $(apt-cache showsrc PACKAGE | grep Build-Depends | perl -p -e 's/(?:[[(].+?[])]|Build-Depends:|,||)//g')

Replace PACKAGE with the name of the package you’ve previously ran apt-get build-dep for, such as kernel or python2.5

After a few moments, the packages will be marked as automatically installed and you will either be prompted to remove them immediately, or you can remove them with the following command, which uninstalls all packages automatically installed but no longer needed:

sudo apt-get autoremove

http://mikebeach.org/2011/04/13/undo-apt-get-build-dep/