If you've just bought a new desktop,laptop or server and the box says the box is powered by 2 processors, you can actually verify that.
Here's how to display the number of processor of your linux box.
Simply issue the following command as root
# cat /proc/cpuinfo | grep processor
Everything in linux is files. This command simply retrieves the number of processors that linux detected from /proc/cpuinfo and displays it. Usually, the processor number comes at the first set of line from issuing the command.
Here's what the command returned for me:
processor : 0
which means You have 1 processor with a processor ID number 0. Processor counting starts with 0.
So if you have a PC with core duo, you will probably have 2 lines that says 0 and 1.That is 2 processors.