Say you need to put some files on 100 USB sticks...

USB_copier.sh

#!/bin/sh

for i in {1..999} 
do
	echo "Waiting for some love"
	while [ ! -s /Volumes/USB\ DISK/ ] 
	do
  		sleep 0.5
		printf "." 
	done
	echo $i
	echo "Making new friends!"

	sleep 0.5
	cp -vr ~/Desktop/tocopy/* /Volumes/USB\ DISK	
	diskutil rename /Volumes/USB\ DISK GAIN
	diskutil unmount /Volumes/GAIN
	printf "hu yeah!"
	echo ""
done

Only work for OSX. Just copy, make it executable and run.
Then you only need to plug it, and wait for it to ask for the next one.