Cloning a USB pendrive to another is easy ... in linux ...

use blkid to find the two drives

example output :

origin = /dev/sdd
destination = /dev /sde

the command is :

dd if=/dev/sdd of=/dev/sde bs=4M

to see dd's progress, find the pid of dd (in another terminal)

ps -a | grep dd 

add a 10 second timer to ask dd how it's doing ... (in another terminal)

watch -n 10 kill -USR1 {pid of dd}

and dd will spit out it's progress ... easy!

excerpts from :