I'm on a Chromebook thats in Developer Mode. Crouton is installed. However, I'm almost out of SSD space for apps. But, I have a new USB drive that I want to install apps on.

I use a chroot, it sayes "xenial"
I dont normaly use the X desktop, I use a chroot term as follows.

1. Open a Term from Chrome <ctrl>+<alt>+<t>
2. Type shell at the crosh prompt e.g. crosh>shell <ENTER>
3. Type sudo enter-chroot
I'm then logged into my chroot as my user.

To install an app (vim for example) I do the following...
$ sudo apt-get install vim <ENTER>

But now I'm out of space on the 16gb Chrome book internal
SSD drive.

How can I install normal apps (like vim etc.) using apt-get install
to my USB drive, without having to compile a program from source?

Thank you,