I have a 64GB flash drive with Linux on it (as if it were a hard drive), which I would like to shrink and add another partition to. But to do that, I need another Linux install to shrink the filesystem.
To do that, I'd like to install a Live CD onto my external hard drive. I have other partitions I would like to keep, and one empty partition I plan to install the image onto.
How can I install the live CD onto the empty partition, without touching my other partitions? There should be no need for a bootloader, since I already have one on my flash drive.
I'm on Mac using EFI, so I should have all the normal BSD command-line tools available, as well as Disk Utility. My auxiliary bootloader is rEFInd, so it should hopefully be able to find the Live CD partition automatically. My problem is the copying part.
I have Etcher installed on my Mac, but it's not seeing the partition by itself, just the whole drive. Weirdly, it is showing my other HFS+ data partitions.
I do have a Linux VM (Parallels) available as well, if that makes things easier, but getting external disks to show up inside it can be tricky. And as an absolute last resort, I also have a Windows 10 partition (if for some reason I need Windows-only software).