Linux find out what process are eating all memory and time allocated to process

Q. How do I find out what process are eating up all my memory. Is it possible to find out how long that memory has been allocated to particular process? How do I kill that process to free up memory?

A. You need to use the top command which provides a dynamic real-time view of a running system. It can display system summary information as well as a list of tasks currently being managed by the Linux kernel.

Simply type top command:
# top

top command will tell you the percentage of physical memory a particular process is using at any given time. As far as I know, there is no easy way that can tell how long that memory has been allocated.

You can also use ps command to get more information about process.
# ps aux | less

To kill process use kill command under Linux. Read man page of top and ls for more information.