Execute programm on Rasberry, DONT wait for answer

Hey guys, im executing a bash file on my raspberry with that matlab command

system(mypi,'bash ~/spidev/ex.sh')

The bashfile removes some old files and than executes a C-Code. My Problem is that matlab is waiting for the program to finish. I tried this:

system(mypi,'bash ~/spidev/ex.sh &')

but its still waiting. Any ideas how to send only the command and instantly proceeding with my own matlab-code???

[Vidya Viswanathan]

Could you provide more information about the contents of the variable "mypi"?

-Vidya