If you want to know top 10 processes which are eating CPU.
$ ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
There are some other commands which show CPU & memory usage :
Install sysstat & try following command, sysstat is not a command.
$ mpstat (to display the utilization of each CPU individually) for multiple cpu systems.
Usage of each cpu
Display today’s CPU activity
iostat command which report (CPU) statistics and I/O statistics for devices and partitions.