How do I install Ubuntu in command-line mode from the Live CD?

Solution 1:

Sorry, that's not possible if you only have the Ubuntu Desktop LiveCD; this is because the LiveCD does not contain the actual .deb packages but instead contains the compressed image of a full Ubuntu install, which is simply unpacked to your hard disk when you install it.

To install a CLI version, you will need the Server or Alternate CDs, or use the minimal "net install" CD.

Solution 2:

If your goal is to have many installs of Ubuntu that are quite similar, but you don't want to have many copies of the same file, then you might want to consider switching to a filesystem that supports copy-on-write and deduplication. BtrFS supports COW, which means you can have about as many copies of a root as you want to without requiring more space on your disk. However, it doesn't support deduplication yet, which probably means you'll start seeing major increases as you install updates. This usually won't be a problem if your machines are short-lived though, so if that's the case, I would consider doing that instead.

Another alternative is if you're using KVM. Then you might want to consider using the qcow2 disk image format instead. This will pretty much give you the same benefits that switching to BtrFS on the host system will do, except you'll do it on the virtual harddisk image instead. You'll create one virtual machine "prototype", then clone its harddisk without requiring more space.

I'm fairly certain copy-on-write is something you'll want to spend some time looking into.