Re: I want to learn Linux but ...
However, if you are trying to install to a USB key rather than a hard drive, while I'm pretty sure that is possible, I wouldn't recommend it. The USB key will be very slow and I don't think it will have a long life if you are continually writing to it.
- It's entirely possible. I've done it several times with USB disk and sticks using the normal install process, and as others point out distros often have a USB-writer tool.
- If you do try the normal install process, be warned that some distros (LinuxMint, I'm looking at you) will overwrite the MBR on /dev/sda (which will likely be your internal disk) with GRUB which might hose up your installed system (especially if you have some sort of software encryption FDE). Pull the disk for the install or install on another system if you can't remove the internal disk.
- Sticks aren't as fast as disk over USB, but USB2 and 3 are fine for basic use even with software encryption. I surrently use a small Sandisk USB3 "stick" (athough it's not much bigger than the USB connector) to boot my corporate laptop into Linux for "home use". I haven't used it extensively, but it's working fine so far. Maybe it'll wear out some day, but I'll just buy another 32GB USB3 stick for $20US and restore from backups.