The Chromebook ships with a limited shell. Developer mode unlocks a slightly better one, but still doesn't give you the ability to install things (that I've found anyway). So I'm gonna advocate for crouton here. It will let you install a full-blown desktop environment, but if you only want command line it works for that too.
These steps will let you run command-line Ubuntu in a Chrome tab:
- put the chromebook into dev mode
- download crouton
- open a shell with
ctrl alt t
shell to access the better shell
cd into the directory you put crouton into and install Ubuntu using:
sudo sh -e crouton -t cli-extra (this uses the
cli-extra target available via crouton, and it's just basic command line Ubuntu, no X, no desktop, etc.)
Now, you have a command-line-only Ubuntu distro installed. To use it:
- open a shell like before with
ctrl alt t
- get into the better shell with
- open the crouton'd chroot using
I did exactly these steps over the summer to do some light C++ work, and it was just so cool to have a whole other OS "inside" a Chrome tab.