What's the caret (^) mean in apt-get?

I'm seeing various instructions that request that you install something like:

apt-get install lamp-server^

With the oddball caret in the command. It doesn't seem to be mentioned in apt-get manual. What's the deal ?

The ^ character is not a typo. If you remove it, apt-get will complain that the package cannot be found.

This article and its comments describe what the caret does:

Well, the answer is that the caret symbol is a short form for performing a task that otherwise the program “tasksel” would have done with the given package name. tasksel is a program to ease the installation of commonly used things that go together for a particular use.

The ^ symbol let you install "Tasks", a set of packages. This can replace tasksel, dedicated tool to work with tasks.

By doing

apt-get install lamp-server^

You are actually running installing a set of packages that would have been installed via the command (even is not exactly the same):

tasksel lamp-server

In other words: Tasks are very similar to meta-packages and live independently of tasksel. You can install tasks without installing tasksel package.