Software delivery fx subcommands

Command Description
add-update-source register dev host as target's update source
build-push build Fuchsia and push to device
mkzedboot make a zedboot USB key
netboot run bootserver for netbooting
ota perform a system OTA on a connected device
pave run bootserver for paving
pave-zedboot run bootserver for paving zedboot
push-package push packages to a device
serve start pave and serve-updates in a single command
serve-updates start the update server and attach to a running fuchsia device
update perform a full update of a target system
delta compare all built Fuchsia packages with a prior package snapshot
save-package-stats take a snapshot of all built Fuchsia packages