To mainly determine how many processors your system has, simply parse /proc/cpuinfo details from command line terminal as shown
# cat /proc/cpuinfo | grep processor | wc -l
The above command shows the total number of processors a system currently have.
This command is helpful specially on remote linux servers wherein you don’t have physical access and you have nobody to tell you how many processors does that remote server have.
Remember that dual core CPU are reported as a separate processor unit.