[notswiley]

If you plug them into a Linux machine and turn on tethering they will show up as the ethernet interface usbx or so. You can then use dhclient to get an address (although you'll want to make sure it doesn't change your default gateway) or assign a reasonable address yourself.

Terminal IDE (on old phones) or termux on new ones should have enough packages to do whatever you want.

You can also grab any rootfs with the right arch and chroot into it if you have root. You can even static link busybox/dropbear and have most of the things you would use on a small server.