How can you tell, from the command line, how many cores are on the machine when you're running Mac OS X? On Linux, I use: x=$(awk '/^processor/ {++n} END {print n+1}' /proc/cpuinfo) It's not perfect, but it's close. This is intended to get fed to make, which is why it gives a result 1 higher than the actual number. And I know the above code can be written denser in Perl or can be written using gre