As apt-get autoremove (suggested by Aaron) will remove all "helper-packages" nothing seems to depend on any longer, sometimes you want to keep some of them for one reason or another. So if that concerns you, another possibility would be:

$(apt-cache depends postgresql|awk '{print "sudo apt-get remove "$NF}')

Using Bash as your shell, this would basically do the following:

1. apt-cache depends postgresql would list all packages the postgresql depends on, including postgresql itself. But each line would look like depends on: <package> -- so we pipe the output to...


2. awk '{print "sudo apt-get remove "$NF}' which would take the last word on each line (which is the package name), and prints it out after preceding it with our intended command: sudo apt-get remove (you could of course also use apt-get purge instead).


3. finally, using the $() construct, we advise Bash to interpret the output as command to be executed.

You could alternatively replace the 3rd step and instead redirect the output into a file:

apt-cache depends postgresql|awk '{print "sudo apt-get remove "$NF}' >pg_remove.sh

And then inspect the file, optionally do some adjustments (such as commenting out/removing lines where you want to keep a package), and finally execute the script using

bash pg_remove.sh

Now you have a lot of possibilities to chose from :)

EDIT: Checking with more complex metapackages as e.g. lubuntu-desktop, above statements needs to be refined:

apt-cache depends <packageName>|grep "Depends on"|awk '{print "sudo apt-get remove "$NF}'

The grep is needed to restrict the result to dependencies (and skip the recommends etc.).

IMPORTANT: You should use this only for metapackages!!! otherwise, you may end up with an empty disk (e.g. postgresql-9.1 depends on libc6, and removing libc6 will certainly backfire as it is needed by a lot of packages).

So be careful, and better redirect to a file first (as explained) and investigate before execution.