TOP(1)                                                        Linux User's Manual                                                       TOP(1)

NAME

       top - display Linux tasks

SYNOPSIS

       top -hv | -bcHisS -d delay -n iterations -p pid [, pid ...]

       The traditional switches '-' and whitespace are optional.

DESCRIPTION

       The  top program 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.  The types of system summary information shown and the  types,  order  and  size  of
       information displayed for tasks are all user configurable and that configuration can be made persistent across restarts.

       The  program  provides a limited interactive interface for process manipulation as well as a much more extensive interface for personal
       configuration  --  encompassing every aspect of its operation.  And while top is referred to throughout this document, you are free  to
       name  the  program  anything you wish.  That new name, possibly an alias, will then be reflected on top's display and used when reading
       and writing a configuration file.

OVERVIEW

   Documentation
       The remaining Table of Contents
           1. COMMAND-LINE Options
           2. FIELDS / Columns
              a. DESCRIPTIONS of Fields
              b. SELECTING and ORDERING Columns
           3. INTERACTIVE Commands
              a. GLOBAL Commands
              b. SUMMARY Area Commands
              c. TASK Area Commands
              d. COLOR Mapping
           4. ALTERNATE-DISPLAY Mode
              a. WINDOWS Overview
              b. COMMANDS for Windows
           5. FILES
              a. SYSTEM Configuration File
              b. PERSONAL Configuration File
           6. STUPID TRICKS Sampler
              a. Kernel Magic
              b. Bouncing Windows
              c. The Big Bird Window
           7. BUGS, 8. HISTORY Former top, 9. AUTHOR, 10. SEE ALSO

   Operation
       When operating top, the two most important keys are help ('h' or '?') and quit ('q') key.  Alternatively,  you  could  simply  use  the
       traditional interrupt key ('^C') when you're done.

       When  you  start  top  for the first time, you'll be presented with the traditional screen elements: 1) Summary Area; 2) Message/Prompt
       Line; 3) Columns Header; 4) Task Area.  There will, however, be some differences when compared to the former top.

       Highlighting
          Summary_Area: There is no highlighting for load/uptime and only values are highlighted for other elements.

          Task_Area: Tasks running (or ready to run) will be highlighted, and bold is only one way of emphasizing such processes.

       Content/Labels
          Summary_Area: The program name is shown, perhaps a symlink or alias.  The Cpu(s) state label  hints  at  other  possibilities.   The
          memory stats use a lower case 'k'.

          Columns_Header: Will show a new field and some changed labels.  More new fields will be found as you customize your top.

       Note:  the  width  of top's display will be limited to 512 positions.  Displaying all fields requires a minimum of 160 characters.  The
       remaining width could be used for the 'Command' column.

   Startup Defaults
       The following startup defaults assume no configuration file, thus no user customizations.  Even so, items shown with an asterisk  ('*')
       could be overridden through the command-line.

           Global_defaults
              'A' - Alt display      Off (full-screen)
            * 'd' - Delay time       3.0 seconds
              'I' - Irix mode        On  (no, 'solaris' smp)
            * 'p' - PID monitoring   Off
            * 's' - Secure mode      Off (unsecured)
              'B' - Bold enable      Off
           Summary_Area_defaults
              'l' - Load Avg/Uptime  On  (thus program name)
              't' - Task/Cpu states  On  (1+1 lines, see '1')
              'm' - Mem/Swap usage   On  (2 lines worth)
              '1' - Single Cpu       On  (thus 1 line if smp)
           Task_Area_defaults
              'b' - Bold hilite      On  (not 'reverse')
            * 'c' - Command line     Off (name, not cmdline)
            * 'H' - Threads          Off (show all threads)
            * 'i' - Idle tasks       On  (show all tasks)
              'R' - Reverse sort     On  (pids high-to-low)
            * 'S' - Cumulative time  Off (no, dead children)
              'x' - Column hilite    Off (no, sort field)
              'y' - Row hilite       On  (yes, running tasks)
              'z' - color/mono       Off (no, colors)

1. COMMAND-LINE Options

       The command-line syntax for top consists of:

            -hv | -bcHisS -d delay -n iterations -p pid [,pid...]

       The typically mandatory switches ('-') and even whitespace are completely optional.

       -b : Batch mode operation
            Starts  top  in 'Batch mode', which could be useful for sending output from top to other programs or to a file.  In this mode, top
            will not accept input and runs until the iterations limit you've set with the '-n' command-line option or until killed.

       -c : Command line/Program name toggle
            Starts top with the last remembered 'c' state reversed.  Thus, if top was displaying command  lines,  now  that  field  will  show
            program names, and visa versa.  See the 'c' interactive command for additional information.

       -d : Delay time interval as:  -d ss.tt (seconds.tenths)
            Specifies  the  delay  between  screen  updates, and overrides the corresponding value in one's personal configuration file or the
            startup default.  Later this can be changed with the 'd' or 's' interactive commands.

            Fractional seconds are honored, but a negative number is not allowed.  In all cases, however, such changes are prohibited  if  top
            is running in 'Secure mode', except for root (unless the 's' command-line option was used).  For additional information on 'Secure
            mode' see topic 5a. SYSTEM Configuration File.

       -h : Help
            Show library version and the usage prompt, then quit.

       -H : Threads toggle
            Starts top with the last remembered 'H' state reversed.  When this toggle  is  On,  all  individual  threads  will  be  displayed.
            Otherwise, top displays a summation of all threads in a process.

       -i : Idle Processes toggle
            Starts  top  with  the  last  remembered 'i' state reversed.  When this toggle is Off, tasks that are idled or zombied will not be
            displayed.

       -n : Number of iterations limit as:  -n number
            Specifies the maximum number of iterations, or frames, top should produce before ending.

       -u : Monitor by user as:  -u somebody
            Monitor only processes with an effective UID or user name matching that given.

       -U : Monitor by user as:  -U somebody
            Monitor only processes with a UID or user name matching that given.  This matches real, effective, saved, and filesystem UIDs.

       -p : Monitor PIDs as:  -pN1 -pN2 ...  or  -pN1, N2 [,...]
            Monitor only processes with specified process IDs.  This option can be given up to 20 times, or you can provide a comma  delimited
            list with up to 20 pids.  Co-mingling both approaches is permitted.

            This  is  a  command-line  option  only.   And  should you wish to return to normal operation, it is not necessary to quit and and
            restart top  --  just issue the '=' interactive command.

       -s : Secure mode operation
            Starts top with secure mode forced, even for root.  This mode is far better controlled through the system configuration file  (see
            topic 5. FILES).

       -S : Cumulative time mode toggle
            Starts  top  with  the last remembered 'S' state reversed.  When 'Cumulative mode' is On, each process is listed with the cpu time
            that it and its dead children have used.  See the 'S' interactive command for additional information regarding this mode.

       -v : Version
            Show library version and the usage prompt, then quit.

2. FIELDS / Columns

   2a. DESCRIPTIONS of Fields
       Listed below are top's available fields.  They are always associated with the letter shown, regardless of the  position  you  may  have
       established for them with the 'o' (Order fields) interactive command.

       Any  field  is  selectable  as  the  sort  field,  and  you control whether they are sorted high-to-low or low-to-high.  For additional
       information on sort provisions see topic 3c. TASK Area Commands.

       a: PID  --  Process Id
          The task's unique process ID, which periodically wraps, though never restarting at zero.

       b: PPID  --  Parent Process Pid
          The process ID of a task's parent.

       c: RUSER  --  Real User Name
          The real user name of the task's owner.

       d: UID  --  User Id
          The effective user ID of the task's owner.

       e: USER  --  User Name
          The effective user name of the task's owner.

       f: GROUP  --  Group Name
          The effective group name of the task's owner.

       g: TTY  --  Controlling Tty
          The name of the controlling terminal.  This is usually the device (serial port, pty, etc.) from which the process was  started,  and
          which it uses for input or output.  However, a task need not be associated with a terminal, in which case you'll see '?' displayed.

       h: PR  --  Priority
          The priority of the task.

       i: NI  --  Nice value
          The  nice value of the task.  A negative nice value means higher priority, whereas a positive nice value means lower priority.  Zero
          in this field simply means priority will not be adjusted in determining a task's dispatchability.

       j: P  --  Last used CPU (SMP)
          A number representing the last used processor.  In a true SMP environment this  will  likely  change  frequently  since  the  kernel
          intentionally uses weak affinity.  Also, the very act of running top may break this weak affinity and cause more processes to change
          CPUs more often (because of the extra demand for cpu time).

       k: %CPU  --  CPU usage
          The task's share of the elapsed CPU time since the last screen update, expressed as a percentage of total CPU time.  In a  true  SMP
          environment,  if 'Irix mode' is Off, top will operate in 'Solaris mode' where a task's cpu usage will be divided by the total number
          of CPUs.  You toggle 'Irix/Solaris' modes with the 'I' interactive command.

       l: TIME  --  CPU Time
          Total CPU time the task has used since it started.  When 'Cumulative mode' is On, each process is listed with the cpu time  that  it
          and  its  dead children has used.  You toggle 'Cumulative mode' with 'S', which is a command-line option and an interactive command.
          See the 'S' interactive command for additional information regarding this mode.

       m: TIME+  --  CPU Time, hundredths
          The same as 'TIME', but reflecting more granularity through hundredths of a second.

       n: %MEM  --  Memory usage (RES)
          A task's currently used share of available physical memory.

       o: VIRT  --  Virtual Image (kb)
          The total amount of virtual memory used by the task.  It includes all code, data and shared libraries  plus  pages  that  have  been
          swapped out and pages that have been mapped but not used.

       p: SWAP  --  Swapped size (kb)
          Memory  that  is  not resident but is present in a task.  This is memory that has been swapped out but could include additional non-
          resident memory.  This column is calculated by subtracting physical memory from virtual memory.

       q: RES  --  Resident size (kb)
          The non-swapped physical memory a task has used.

       r: CODE  --  Code size (kb)
          The amount of virtual memory devoted to executable code, also known as the 'text resident set' size or TRS.

       s: DATA  --  Data+Stack size (kb)
          The amount of virtual memory devoted to other than executable code, also known as the 'data resident set' size or DRS.

       t: SHR  --  Shared Mem size (kb)
          The amount of shared memory used by a task.  It simply reflects memory that could be potentially shared with other processes.

       u: nFLT  --  Page Fault count
          The number of major page faults that have occurred for a task.  A page fault occurs when a process attempts to read from or write to
          a  virtual  page  that  is not currently present in its address space.  A major page fault is when backing storage access (such as a
          disk) is involved in making that page available.

       v: nDRT  --  Dirty Pages count
          The number of pages that have been modified since they were last written to disk.  Dirty pages must be written to  disk  before  the
          corresponding physical memory location can be used for some other virtual page.

       w: S  --  Process Status
          The status of the task which can be one of:
             'D' = uninterruptible sleep
             'R' = running
             'S' = sleeping
             'T' = traced or stopped
             'Z' = zombie

          Tasks  shown  as  running  should  be more properly thought of as 'ready to run'  --  their task_struct is simply represented on the
          Linux run-queue.  Even without a true SMP machine, you may see numerous tasks in this state depending on top's  delay  interval  and
          nice value.

       x: Command  --  Command line or Program name
          Display  the command line used to start a task or the name of the associated program.  You toggle between command line and name with
          'c', which is both a command-line option and an interactive command.

          When you've chosen to display command lines, processes without a command line (like kernel threads) will  be  shown  with  only  the
          program name in parentheses, as in this example:
                ( mdrecoveryd )

          Either form of display is subject to potential truncation if it's too long to fit in this field's current width.  That width depends
          upon other fields selected, their order and the current screen width.

          Note: The 'Command' field/column is unique, in that it is not fixed-width.  When  displayed,  this  column  will  be  allocated  all
          remaining screen width (up to the maximum 512 characters) to provide for the potential growth of program names into command lines.

       y: WCHAN  --  Sleeping in Function
          Depending  on  the  availability  of  the kernel link map ('System.map'), this field will show the name or the address of the kernel
          function in which the task is currently sleeping.  Running tasks will display a dash ('-') in this column.

          Note: By displaying this field, top's own working set will be increased by over 700Kb.  Your only means of  reducing  that  overhead
          will be to stop and restart top.

       z: Flags  --  Task Flags
          This  column  represents  the task's current scheduling flags which are expressed in hexadecimal notation and with zeros suppressed.
          These flags are officially documented in <linux/sched.h>.  Less formal documentation can also be found on the  'Fields  select'  and
          'Order fields' screens.

   2b. SELECTING and ORDERING Columns
       After  pressing  the  interactive  commands 'f' (Fields select) or 'o' (Order fields) you will be shown a screen containing the current
       fields string followed by names and descriptions for all fields.

       Here is a sample fields string from one of top's four windows/field groups and an explanation of the conventions used:

       -  Sample fields string:
             ANOPQRSTUVXbcdefgjlmyzWHIK

       -  The order of displayed fields corresponds to the order of the letters in that string.

       -  If the letter is upper case the corresponding field itself will then be shown as part of the task display (screen width permitting).
          This will also be indicated by a leading asterisk ('*'), as in this excerpt:
              ...
              * K: %CPU       = CPU usage
                l: TIME       = CPU Time
                m: TIME+      = CPU Time, hundredths
              * N: %MEM       = Memory usage (RES)
              * O: VIRT       = Virtual Image (kb)
              ...

       Fields select screen  --  the 'f' interactive command
          You toggle the display of a field by simply pressing the corresponding letter.

       Order fields screen  --  the 'o' interactive command
          You move a field to the left by pressing the corresponding upper case letter and to the right with the lower case letter.

   2c. CPU States
       The  CPU  states  are  shown  in  the Summary Area. They are always shown as a percentage and are for the time between now and the last
       refresh.

        us  --  User CPU time
          The time the CPU has spent running users' processes that are not niced.

        sy  --  System CPU time
          The time the CPU has spent running the kernel and its processes.

        ni  --  Nice CPU time
          The time the CPU has spent running users' proccess that have been niced.

        wa  --  iowait
          Amount of time the CPU has been waiting for I/O to complete.

        hi  --  Hardware IRQ
          The amount of time the CPU has been servicing hardware interrupts.

        si  --  Software Interrupts
          The amount of time the CPU has been servicing software interrupts.

        st  --  Steal Time
          The amount of CPU 'stolen' from this virtual machine by the hypervisor for other tasks (such as running another virtual machine).

3. INTERACTIVE Commands

       Listed below is a brief index of commands within categories.  Some commands appear more than once  --  their meaning or scope may  vary
       depending on the context in which they are issued.

         3a. GLOBAL_Commands
               <Ret/Sp> ?, =, A, B, d, G, h, I, k, q, r, s, W, Z
         3b. SUMMARY_Area_Commands
               l, m, t, 1
         3c. TASK_Area_Commands
               Appearance:  b, x, y, z
               Content:     c, f, H, o, S, u
               Size:        #, i, n
               Sorting:     <, >, F, O, R
         3d. COLOR_Mapping
               <Ret>, a, B, b, H, M, q, S, T, w, z, 0 - 7
         4b. COMMANDS_for_Windows
               -, _, =, +, A, a, G, g, w

   3a. GLOBAL Commands
       The  global  interactive  commands  are  always  available in both full-screen mode and alternate-display mode.  However, some of these
       interactive commands are not available when running in 'Secure mode'.

       If you wish to know in advance whether or not your top has been secured, simply ask for help and view the system summary on the  second
       line.

         <Enter> or <Space> :Refresh_Display
              These commands do nothing, they are simply ignored.  However, they will awaken top and following receipt of any input the entire
              display will be repainted.

              Use either of these keys if you have a large delay interval and wish to see current status,

         <?> or <h> :Help
              There are two help levels available.  The first will provide a reminder of all  the  basic  interactive  commands.   If  top  is
              secured, that screen will be abbreviated.

              Typing 'h' or '?' on that help screen will take you to help for those interactive commands applicable to alternate-display mode.

         <=> :Exit_Task_Limits
              Removes restrictions on which tasks are shown.  This command will reverse any 'i' (idle tasks) and 'n' (max tasks) commands that
              might be active.  It also provides for an 'exit' from PID monitoring.  See the '-p' command-line option for a discussion of  PID
              monitoring.

              When operating in alternate-display mode this command has a slightly broader meaning.

         <A> :Alternate_Display_Mode_toggle
              This  command  will switch between full-screen mode and alternate-display mode.  See topic 4. ALTERNATE-DISPLAY Mode and the 'G'
              interactive command for insight into ´current' windows and field groups.

         <B> :Bold_Disable/Enable_toggle
              This command will influence use of the 'bold' terminfo capability and alters both  the  summary  area  and  task  area  for  the
              ´current' window.  While it is intended primarily for use with dumb terminals, it can be applied anytime.

              Note:  When  this  toggle  is  On and top is operating in monochrome mode, the entire display will appear as normal text.  Thus,
              unless the 'x' and/or 'y' toggles are using reverse for emphasis, there will be no visual confirmation that they are even on.

       * <d> or <s> :Change_Delay_Time_interval
              You will be prompted to enter the delay time, in seconds, between display updates.

              Fractional seconds are honored, but a negative number is not allowed.  Entering 0 causes (nearly) continuous  updates,  with  an
              unsatisfactory  display  as  the  system  and  tty  driver  try  to  keep  up  with top's demands.  The delay value is inversely
              proportional to system loading, so set it with care.

              If at any time you wish to know the current delay time, simply ask for help and view the system summary on the second line.

         <G> :Choose_Another_Window/Field_Group
              You will be prompted to enter a number between 1 and 4 designating the window/field group which should  be  made  the  ´current'
              window.  You will soon grow comfortable with these 4 windows, especially after experimenting with alternate-display mode.

         <I> :Irix/Solaris_Mode_toggle
              When  operating  in  'Solaris  mode'  ('I'  toggled Off), a task's cpu usage will be divided by the total number of CPUs.  After
              issuing this command, you'll be informed of the new state of this toggle.

         <u> :select a user
              You will be prompted for a UID or username. Only processes belonging to the selected user will be displayed. This option matches
              on the effective UID.

         <U> :select a user
              You will be prompted for a UID or username. Only processes belonging to the selected user will be displayed. This option matches
              on the real, effective, saved, and filesystem UID.

       * <k> :Kill_a_task
              You will be prompted for a PID and then the signal to send.  The default  signal,  as  reflected  in  the  prompt,  is  SIGTERM.
              However, you can send any signal, via number or name.

              If you wish to abort the kill process, do one of the following depending on your progress:
                 1) at the pid prompt, just press <Enter>
                 2) at the signal prompt, type 0

         <q> :Quit

       * <r> :Renice_a_Task
              You  will  be  prompted  for  a  PID  and  then the value to nice it to.  Entering a positive value will cause a process to lose
              priority.  Conversely, a negative value will cause a process to be viewed more favorably by the kernel.

         <W> :Write_the_Configuration_File
              This will save all of your options and toggles plus the current display mode and delay  time.   By  issuing  this  command  just
              before quitting top, you will be able restart later in exactly that same state.

         <Z> :Change_Color_Mapping
              This  key  will take you to a separate screen where you can change the colors for the ´current' window, or for all windows.  For
              details regarding this interactive command see topic 3d. COLOR Mapping.

       *  The commands shown with an asterisk ('*') are not available in 'Secure mode', nor will they be shown on the level-1 help screen.

   3b. SUMMARY Area Commands
       The summary area interactive commands are always available in both full-screen  mode  and  alternate-display  mode.   They  affect  the
       beginning lines of your display and will determine the position of messages and prompts.

       These  commands  always  impact  just  the  ´current'  window/field group.  See topic 4. ALTERNATE-DISPLAY Mode and the 'G' interactive
       command for insight into ´current' windows and field groups.

         <l> :Toggle_Load_Average/Uptime  --  On/Off
              This is also the line containing the program name (possibly an alias) when operating in full-screen mode or the ´current' window
              name when operating in alternate-display mode.

         <m> :Toggle_Memory/Swap_Usage  --  On/Off
              This command affects two summary area lines.

         <t> :Toggle_Task/Cpu_States  --  On/Off
              This  command  affects  from  2  to  many summary area lines, depending on the state of the '1' toggle and whether or not top is
              running under true SMP.

         <1> :Toggle_Single/Separate_Cpu_States  --  On/Off
              This command affects how the 't' command's Cpu States portion  is  shown.   Although  this  toggle  exists  primarily  to  serve
              massively-parallel SMP machines, it is not restricted to solely SMP environments.

              When  you  see  'Cpu(s):'  in  the  summary  area,  the  '1'  toggle is On and all cpu information is gathered in a single line.
              Otherwise, each cpu is displayed separately as: 'Cpu0, Cpu1, ...'

       Note: If the entire summary area has been toggled Off for any window, you would be left with just the message line.  In that  way,  you
       will  have maximized available task rows but (temporarily) sacrificed the program name in full-screen mode or the ´current' window name
       when in alternate-display mode.

   3c. TASK Area Commands
       The task area interactive commands are always available in full-screen mode.

       The task area interactive commands are never available in alternate-display mode if  the  ´current'  window's  task  display  has  been
       toggled Off (see topic 4. ALTERNATE-DISPLAY Mode).

       APPEARANCE of task window
         The following commands will also be influenced by the state of the global 'B' (bold disable) toggle.

         <b> :Bold/Reverse_toggle
              This  command  will  impact  how the 'x' and 'y' toggles are displayed.  Further, it will only be available when at least one of
              those toggles is On.

         <x> :Column_Highlight_toggle
              Changes highlighting for the current sort field.  You probably don't need a constant visual reminder of the sort field  and  top
              hopes that you always run with 'column highlight' Off, due to the cost in path-length.

              If you forget which field is being sorted this command can serve as a quick visual reminder.

         <y> :Row_Highlight_toggle
              Changes  highlighting  for  "running" tasks.  For additional insight into this task state, see topic 2a. DESCRIPTIONS of Fields,
              Process Status.

              Use of this provision provides important insight into your system's health.  The only costs will be a few additional tty  escape
              sequences.

         <z> :Color/Monochrome_toggle
              Switches  the ´current' window between your last used color scheme and the older form of black-on-white or white-on-black.  This
              command will alter both the summary area and task area but does not affect the state of the 'x', 'y' or 'b' toggles.

       CONTENT of task window
         <c> :Command_Line/Program_Name_toggle
              This command will be honored whether or not the 'Command' column is currently visible.  Later, should that field come into view,
              the change you applied will be seen.

         <f> and <o> :Fields_select or Order_fields
              These keys display separate screens where you can change which fields are displayed and their order.  For additional information
              on these interactive commands see topic 2b. SELECTING and ORDERING Columns.

         <S> :Cumulative_Time_Mode_toggle
              When this toggle is On, all individual threads will be displayed.  Otherwise, top displays a  summation  of  all  threads  in  a
              process.

         ´S´ :Cumulative_Time_Mode_toggle
              When 'Cumulative mode' is On, each process is listed with the cpu time that it and its dead children have used.

              When  Off,  programs that fork into many separate tasks will appear less demanding.  For programs like 'init' or a shell this is
              appropriate but for others, like compilers, perhaps not.  Experiment with two task windows sharing the same sort field but  with
              different 'S' states and see which representation you prefer.

              After  issuing  this command, you'll be informed of the new state of this toggle.  If you wish to know in advance whether or not
              'Cumulative mode' is in effect, simply ask for help and view the window summary on the second line.

         <u> :Show_Specific_User_Only
              You will be prompted to enter the name of the user to display.  Thereafter, in that task window only matching User ID's will  be
              shown, or possibly no tasks will be shown.

              Later,  if  you wish to monitor all tasks again, re-issue this command but just press <Enter> at the prompt, without providing a
              name.

       SIZE of task window
         <i> :Idle_Processes_toggle
              Displays all tasks or just active tasks.  When this toggle is Off, idled or zombied processes will not be displayed.

              If this command is applied to the last task display when in alternate-display mode, then it will not affect the  window's  size,
              as all prior task displays will have already been painted.

         <n> or <#> :Set_Maximum_Tasks
              You will be prompted to enter the number of tasks to display.  The lessor of your number and available screen rows will be used.

              When  used in alternate-display mode, this is the command that gives you precise control over the size of each currently visible
              task display, except for the very last.  It will not affect the last window's size, as all prior task displays will have already
              been painted.

              Note: If you wish to increase the size of the last visible task display when in alternate-display mode, simply decrease the size
              of the task display(s) above it.

       SORTING of task window
         For compatibility, this top supports most of the former top sort keys.  Since this is primarily a service to former top users,  these
         commands do not appear on any help screen.
            command   sorted field                  supported
              A         start time (non-display)      No
              M         %MEM                          Yes
              N         PID                           Yes
              P         %CPU                          Yes
              T         TIME+                         Yes

         Before  using  any  of  the  following  sort  provisions, top suggests that you temporarily turn on column highlighting using the 'x'
         interactive command.  That will help ensure that the actual sort environment matches your intent.

         The following interactive commands will only be honored when the current sort field is visible.  The sort field might not be  visible
         because:
              1) there is insufficient Screen Width
              2) the 'f' interactive command turned it Off

         <<> :Move_Sort_Field_Left
              Moves the sort column to the left unless the current sort field is the first field being displayed.

         <>> :Move_Sort_Field_Right
              Moves the sort column to the right unless the current sort field is the last field being displayed.

         The following interactive commands will always be honored whether or not the current sort field is visible.

         <F> or <O> :Select_Sort_Field
              These keys display a separate screen where you can change which field is used as the sort column.

              If  a  field  is  selected  which  was  not previously being displayed, it will be forced On when you return to the top display.
              However, depending upon your screen width and the order of your fields, this sort field may not be displayable.

              This interactive command can be a convenient way to simply  verify  the  current  sort  field,  when  running  top  with  column
              highlighting turned Off.

         <R> :Reverse/Normal_Sort_Field_toggle
              Using this interactive command you can alternate between high-to-low and low-to-high sorts.

         Note:  Field  sorting  uses  internal  values, not those in column display.  Thus, the TTY and WCHAN fields will violate strict ASCII
         collating sequence.

   3d. COLOR Mapping
       When you issue the 'Z' interactive command, you will be presented with a separate screen.  That screen can be used to change the colors
       in just the ´current' window or in all four windows before returning to the top display.

       Available interactive commands
           4 upper case letters to select a target
           8 numbers to select a color
           normal toggles available
               'B'       :bold disable/enable
               'b'       :running tasks "bold"/reverse
               'z'       :color/mono
           other commands available
               'a'/'w'   :apply, then go to next/prior
               <Enter>   :apply and exit
               'q'       :abandon current changes and exit

       If  your  use  'a'  or  'w'  to cycle the targeted window, you will have applied the color scheme that was displayed when you left that
       window.  You can, of course, easily return to any window and reapply different colors or  turn  colors  Off  completely  with  the  'z'
       toggle.

       The  Color  Mapping  screen can also be used to change the ´current' window/field group in either full-screen mode or alternate-display
       mode.  Whatever was targeted when 'q' or <Enter> was pressed will be made current as you return to the top display.

4. ALTERNATE-DISPLAY Mode

   4a. WINDOWS Overview
       Field Groups/Windows:
              In full-screen mode there is a single window represented by the entire screen.  That single  window  can  still  be  changed  to
              display  1  of  4  different  field  groups (see the 'G' interactive command, repeated below).  Each of the 4 field groups has a
              unique separately configurable summary area and its own configurable task area.

              In alternate-display mode, those 4 underlying field groups can now  be  made  visible  simultaneously,  or  can  be  turned  Off
              individually at your command.

              The  summary  area  will  always  exist,  even  if  it's  only the message line.  At any given time only one summary area can be
              displayed.  However, depending on your commands, there could be from zero to four separate task displays  currently  showing  on
              the screen.

       Current Window:
              The  ´current'  window  is  the window associated with the summary area and the window to which task related commands are always
              directed.  Since in alternate-display mode you can toggle the task display Off,  some  commands  might  be  restricted  for  the
              ´current' window.

              A  further complication arises when you have toggled the first summary area line Off.  With the loss of the window name (the 'l'
              toggled line), you'll not easily know what window is the ´current' window.

   4b. COMMANDS for Windows
         <-> and <_> :Show/Hide_Window(s)_toggles
              The '-' key turns the ´current' window's task display On and Off.  When On, that task area will show a minimum  of  the  columns
              header  you've  established  with  the  'f'  and  'o' commands.  It will also reflect any other task area options/toggles you've
              applied yielding zero or more tasks.

              The '_' key does the same for all task displays.  In other words, it switches between the currently visible task display(s)  and
              any  task display(s) you had toggled Off.  If all 4 task displays are currently visible, this interactive command will leave the
              summary area as the only display element.

       * <=> and <+> :Equalize_(re-balance)_Window(s)
              The '=' key forces the ´current' window's task display to be visible.  It also reverses any 'i' (idle tasks) and 'n' (max tasks)
              commands that might be active.

              The '+' key does the same for all windows.  The four task displays will reappear, evenly balanced.  They will also have retained
              any customizations you had previously applied, except for the 'i' (idle tasks) and 'n' (max tasks) commands.

       * <A> :Alternate_Display_Mode_toggle
              This command will switch between full-screen mode and alternate-display mode.

              The first time you issue this command, all four task displays will be shown.  Thereafter when you switch  modes,  you  will  see
              only the task display(s) you've chosen to make visible.

       * <a> and <w> :Next_Window_Forward/Backward
              This  will  change  the  ´current' window, which in turn changes the window to which commands are directed.  These keys act in a
              circular fashion so you can reach any desired ´current' window using either key.

              Assuming the window name is visible (you have not toggled 'l' Off), whenever the ´current' window name loses its emphasis/color,
              that's a reminder the task display is Off and many commands will be restricted.

       * <G> :Choose_Another_Window/Field_Group
              You  will  be  prompted  to enter a number between 1 and 4 designating the window/field group which should be made the ´current'
              window.

              In full-screen mode, this command is necessary to alter the ´current' window.  In alternate-display mode, it is  simply  a  less
              convenient alternative to the 'a' and 'w' commands.

         <g> :Change_Window/Field_Group_Name
              You  will be prompted for a new name to be applied to the ´current' window.  It does not require that the window name be visible
              (the 'l' toggle to be On).

       *  The interactive commands shown with an asterisk ('*') have use beyond alternate-display mode.
              '=', 'A', 'G'  are always available
              'a', 'w'       act the same when color mapping

5. FILES

   5a. SYSTEM Configuration File
       The presence of this file will influence which version of the 'help' screen is shown to an ordinary user.  More  importantly,  it  will
       limit what ordinary users are allowed to do when top is running.  They will not be able to issue the following commands.
          k         Kill a task
          r         Renice a task
          d or s    Change delay/sleep interval

       The  system  configuration  file is not created by top.  Rather, you create this file manually and place it in the /etc directory.  Its
       name must be 'toprc' and must have no leading '.' (period).  It must have only two lines.

       Here is an example of the contents of /etc/toprc:
          s         # line 1: 'secure' mode switch
          5.0       # line 2: 'delay'  interval in seconds

   5b. PERSONAL Configuration File
       This file is written as '$HOME/.your-name-4-top' + 'rc'.  Use the 'W' interactive command to create it or update it.

       Here is the general layout:
          global    # line 1: the program name/alias notation
            "       # line 2: id,altscr,irixps,delay,curwin
          per ea    # line a: winname,fieldscur
          window    # line b: winflags,sortindx,maxtasks
            "       # line c: summclr,msgsclr,headclr,taskclr

       If the $HOME variable is not present, top will try to write the personal configuration  file  to  the  current  directory,  subject  to
       permissions.

6. STUPID TRICKS Sampler

       Many  of  these  'tricks'  work  best when you give top a scheduling boost.  So plan on starting him with a nice value of -10, assuming
       you've got the authority.

   6a. Kernel Magic
       For these stupid tricks, top needs full-screen mode.

       -*-  The user interface, through prompts and help, intentionally implies that the delay interval is limited  to  tenths  of  a  second.
            However,  you're  free  to  set any desired delay.  If you want to see Linux at his scheduling best, try a delay of .09 seconds or
            less.

            For this experiment, under x-windows open an xterm and maximize it.  Then do the following:
              . provide a scheduling boost and tiny delay via:
                  nice -n -10 top -d.09
              . keep sorted column highlighting Off to minimize
                path length
              . turn On reverse row highlighting for emphasis
              . try various sort columns (TIME/MEM work well),
                and normal or reverse sorts to bring the most
                active processes into view

            What you'll see is a very busy Linux doing what he's always done for you, but there was no program available to illustrate this.

       -*-  Under an xterm using 'white-on-black' colors, try setting top's task color to black and be sure that task highlighting is  set  to
            bold, not reverse.  Then set the delay interval to around .3 seconds.

            After bringing the most active processes into view, what you'll see are the ghostly images of just the currently running tasks.

       -*-  Delete  the existing rcfile, or create a new symlink.  Start this new version then type 'T' (a secret key, see topic 3c. TASK Area
            Commands, Sorting) followed by 'W' and 'q'.  Finally, restart the program with -d0 (zero delay).

            Your display will be refreshed at three times the rate of the former top, a 300% speed advantage.  As top climbs the TIME  ladder,
            be as patient as you can while speculating on whether or not top will ever reach the top.

   6b. Bouncing Windows
       For these stupid tricks, top needs alternate-display mode.

       -*-  With  3  or  4  task  displays  visible,  pick any window other than the last and turn idle processes Off.  Depending on where you
            applied 'i', sometimes several task displays are bouncing and sometimes it's like an accordion, as top tries his best to  allocate
            space.

       -*-  Set  each  window's summary lines differently: one with no memory; another with no states; maybe one with nothing at all, just the
            message line.  Then hold down 'a' or 'w' and watch a variation on bouncing windows  --  hopping windows.

       -*-  Display all 4 windows and for each, in turn, set idle processes to Off.  You've just entered the "extreme bounce" zone.

   6c. The Big Bird Window
       This stupid trick also requires alternate-display mode.

       -*-  Display all 4 windows and make sure that 1:Def is the ´current' window.  Then, keep increasing window size until the all the other
            task displays are "pushed out of the nest".

            When they've all been displaced, toggle between all visible/invisible windows.  Then ponder this:
               is top fibbing or telling honestly your imposed truth?

7. BUGS

       Send bug reports to:
          Albert D. Cahalan, <albert@users.sf.net>

8. HISTORY Former top

       The original top was written by Roger Binns, based on Branko Lankester's <lankeste@fwi.uva.nl> ps program.

       Robert Nation <nation@rocket.sanders.lockheed.com> adapted it for the proc file system.

       Helmut Geyer <Helmut.Geyer@iwr.uni-heidelberg.de> added support for configurable fields.

       Plus many other individuals contributed over the years.

9. AUTHOR

       This entirely new and enhanced replacement was written by:
          Jim / James C. Warner, <warnerjc@worldnet.att.net>

       With invaluable help from:
          Albert D. Cahalan, <albert@users.sf.net>
          Craig Small, <csmall@small.dropbear.id.au>

10. SEE ALSO

       free(1), ps(1), uptime(1), atop(1), slabtop(1), vmstat(8), w(1).
 

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