Device management fx subcommands

Command Description
cp copy a file to/from a target device
flash flash and, optionally, pave a connected device
node-names find other names for the same node
reboot reboot a target fuchsia system
scp invoke scp with the build ssh config
serial attach to a serial console
sftp invoke sftp with the build ssh config
shell start a remote interactive shell in the target device
ssh invoke ssh with the keys from $FUCHSIA_BUILD_DIR/ssh-keys
wait wait for a shell to become available
fastboot interact directly with a device's bootloader via the fastboot protocol