To start 4 cpus :
$ julia -p 3
_
_ _ _(_)_ | A fresh approach to technical computing
(_) | (_) (_) | Documentation: http://docs.julialang.org
_ _ _| |_ __ _ | Type "?help" for help.
| | | | | | |/ _` | |
| | |_| | | | (_| | | Version 0.4.5 (2016-03-18 00:58 UTC)
_/ |\__'_|_|_|\__'_| | Official http://julialang.org release
|__/ | x86_64-linux-gnujulia> nprocs() 4
