Use Task Manager on Ubuntu
To open System Monitor (Task Manager) on Ubuntu, search for System Monitor on Ubuntu Dash and click on it. You can also open System Monitor from Linux Terminal, to open run:
Once opened, you can see the System Monitor. It have tabs : Processes, Resources and File Systems.
The Processes tab: shows all the running process on the Linux Ubuntu System. It displays the Process Name, user, %CPU, Process ID, Memory and Priority used by the Process.
To kill or remove any unwanted Process, right click on process. You will then get various options such as Stop, Continue, End, Kill, Change Priority, Memory Maps, Open Files and Properties.
Resources tab: This displays the Resources analytic for the system – CPU History, Memory and Swap History and Network History.
File Systems tab:The File Systems tab shows the information about the Hard Disk Device. It shows information such as Device, Directory, Type, Total Size, Available and Used Disk size.