top -- display top CPU processes

  1. top provides  an  ongoing look at processor activity in real time.  It displays a listing of the most CPU-intensive tasks on the system, and can provide an interactive interface for manipulating processes.  It can sort the tasks by CPU usage, memory usage and runtime.
  2. The first line at the top of the screen shows
    • top (name of program) - current time
    • uptime in days, hours and minutes
    • number of users on system
    • load average - now, 5 minutes ago and 10 minutes ago
  3. The second line shows:
    • Tasks, total number
    • Number of running tasks
    • Number of sleeping tasks,
    • Number of stopped tasks
    • Number of zombie tasks
  4. Third line shows CPU usage
    • Percent taken by users
    • Percent taken by system
    • Percent take by niced programs
    • %id
    • %ua
    • %hi
    • %si
    • %st
  5. Fourth line shows memory usage
    • Total memory
    • Amount used
    • Amount Free
    • Number of buffers
  6. Fifth line shows swap usage
    • Swap total
    • Amount used
    • Amount free
    • Amount cached
  7. Next line is a header line that shows what information is displayed for each process
    • PID -- Process ID
    • USER -- Effective user name of the task’s owner
    • RUSER -- Real User Name of the task’s owner
    • PR -- Priority
    • NI -- Nice value
    • VIRT -- Virtual Image (kb)
    • RES - Resident size (kb)
    • SHR -- Shared Mem size (kb)
    • S -- Process Status
    • %CPU -- CPU usage
    • %MEM -- Memory usage (RES)
    • TIME -- Total CPU time
    • COMMAND -- Command line or Program name
  8. All the rest of the lines will be actual processes that are running on the system.
  9. To change sort columns
    • Press f (field).
    • Move cursor to column you want to use to sort on.
    • Press s to set the sort option.

Press q to return to previous page.