ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head
Brief explanation of above options used in above command.
The -o (or –format) option of ps allows you to specify the output format. A favorite of mine is to show the processes’ PIDs (pid), PPIDs (pid), the name of the executable file associated with the process (cmd), and the RAM and CPU utilization (%mem and %cpu, respectively).
Additionally, I use --sort to sort by either %mem or %cpu. By default, the output will be sorted in ascendant form, but personally I prefer to reverse that order by adding a minus sign in front of the sort criteria.
To add other fields to the output, or change the sort criteria, refer to the OUTPUT FORMAT CONTROL section in the man page of ps command.