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NAME

       top - display Linux processes

SYNOPSIS

       top -hv|-bcEeHiOSs1 -d secs -n max -u|U user -p pids -o field -w [cols]

       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  processes  or  threads  currently  being
       managed by the Linux kernel.  The types of system summary information shown and the types,
       order and size of information displayed for processes 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

           OVERVIEW
              Operation
              Linux Memory Types
           1. COMMAND-LINE Options
           2. SUMMARY Display
              a. UPTIME and LOAD Averages
              b. TASK and CPU States
              c. MEMORY Usage
           3. FIELDS / Columns Display
              a. DESCRIPTIONS of Fields
              b. MANAGING Fields
           4. INTERACTIVE Commands
              a. GLOBAL Commands
              b. SUMMARY AREA Commands
              c. TASK AREA Commands
                 1. Appearance
                 2. Content
                 3. Size
                 4. Sorting
              d. COLOR Mapping
           5. ALTERNATE-DISPLAY Provisions
              a. WINDOWS Overview
              b. COMMANDS for Windows
              c. SCROLLING a Window
              d. SEARCHING in a Window
              e. FILTERING in a Window
           6. FILES
              a. PERSONAL Configuration File
              b. ADDING INSPECT Entries
              c. SYSTEM Configuration File
              d. SYSTEM Restrictions File
           7. STUPID TRICKS Sampler
              a. Kernel Magic
              b. Bouncing Windows
              c. The Big Bird Window
              d. The Ol' Switcheroo
           8. BUGS, 9. SEE Also

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

       When  started  for  the first time, you'll be presented with these traditional elements on
       the main top screen: 1) Summary Area; 2) Fields/Columns Header; 3)  Task  Area.   Each  of
       these  will  be explored in the sections that follow.  There is also an Input/Message line
       between the Summary Area and Columns Header which needs no further explanation.

       The main top screen is generally quite adaptive to changes in terminal dimensions under X-
       Windows.   Other  top  screens  may  be  less  so,  especially those with static text.  It
       ultimately depends, however, on your particular  window  manager  and  terminal  emulator.
       There  may be occasions when their view of terminal size and current contents differs from
       top's view, which is always based on operating system calls.

       Following any re-size operation, if a top  screen  is  corrupted,  appears  incomplete  or
       disordered,  simply  typing  something  innocuous  like  a punctuation character or cursor
       motion key will usually restore it.  In  extreme  cases,  the  following  sequence  almost
       certainly will:
              key/cmd  objective
              ^Z       suspend top
              fg       resume top
              <Left>   force a screen redraw (if necessary)

       But  if the display is still corrupted, there is one more step you could try.  Insert this
       command after top has been suspended but before resuming it.
              key/cmd  objective
              reset    restore your terminal settings

       Note: the width of top's display will be limited to 512 positions.  Displaying all  fields
       requires approximately 250 characters.  Remaining screen width is usually allocated to any
       variable width columns currently visible.  The variable width columns,  such  as  COMMAND,
       are noted in topic 3a. DESCRIPTIONS of Fields.  Actual output width may also be influenced
       by the -w switch, which is discussed in topic 1. COMMAND-LINE Options.

       Lastly, some of top's screens or functions require the use of cursor motion keys like  the
       standard  arrow keys plus the Home, End, PgUp and PgDn keys.  If your terminal or emulator
       does not provide those keys, the following combinations are accepted as alternatives:
              key      equivalent-keys
              Left     alt + h
              Down     alt + j
              Up       alt + k
              Right    alt + l
              Home     alt + ctrl + h
              PgDn     alt + ctrl + j
              PgUp     alt + ctrl + k
              End      alt + ctrl + l

       The Up and Down arrow  keys  have  special  significance  when  prompted  for  line  input
       terminated  with  the  <Enter> key.  Those keys, or their aliases, can be used to retrieve
       previous input lines which can then be edited and re-input.  And there are four additional
       keys available with line oriented input.
              key      special-significance
              Up       recall older strings for re-editing
              Down     recall newer strings or erase entire line
              Insert   toggle between insert and overtype modes
              Delete   character removed at cursor, moving others left
              Home     jump to beginning of input line
              End      jump to end of input line

   Linux Memory Types
       For  our purposes there are three types of memory, and one is optional.  First is physical
       memory, a limited resource where code and data must reside when  executed  or  referenced.
       Next  is  the  optional  swap  file,  where modified (dirty) memory can be saved and later
       retrieved if too many demands are made on physical memory.  Lastly we have virtual memory,
       a nearly unlimited resource serving the following goals:

          1. abstraction, free from physical memory addresses/limits
          2. isolation, every process in a separate address space
          3. sharing, a single mapping can serve multiple needs
          4. flexibility, assign a virtual address to a file

       Regardless  of  which  of these forms memory may take, all are managed as pages (typically
       4096 bytes) but expressed by default in top as KiB (kibibyte).  The memory discussed under
       topic  `2c. MEMORY Usage' deals with physical memory and the swap file for the system as a
       whole.  The memory reviewed in topic `3. FIELDS /  Columns  Display'  embraces  all  three
       memory types, but for individual processes.

       For each such process, every memory page is restricted to a single quadrant from the table
       below.  Both physical memory and virtual memory can include any of  the  four,  while  the
       swap  file only includes #1 through #3.  The memory in quadrant #4, when modified, acts as
       its own dedicated swap file.

                                     Private | Shared
                                 1           |          2
            Anonymous  . stack               |
                       . malloc()            |
                       . brk()/sbrk()        | . POSIX shm*
                       . mmap(PRIVATE, ANON) | . mmap(SHARED, ANON)
                      -----------------------+----------------------
                       . mmap(PRIVATE, fd)   | . mmap(SHARED, fd)
          File-backed  . pgms/shared libs    |
                                 3           |          4

       The following may help in interpreting process level memory values displayed  as  scalable
       columns and discussed under topic `3a. DESCRIPTIONS of Fields'.

          %MEM - simply RES divided by total physical memory
          CODE - the `pgms' portion of quadrant 3
          DATA - the entire quadrant 1 portion of VIRT plus all
                 explicit mmap file-backed pages of quadrant 3
          RES  - anything occupying physical memory which, beginning with
                 Linux-4.5, is the sum of the following three fields:
                 RSan - quadrant 1 pages, which include any
                        former quadrant 3 pages if modified
                 RSfd - quadrant 3 and quadrant 4 pages
                 RSsh - quadrant 2 pages
          RSlk - subset of RES which cannot be swapped out (any quadrant)
          SHR  - subset of RES (excludes 1, includes all 2 & 4, some 3)
          SWAP - potentially any quadrant except 4
          USED - simply the sum of RES and SWAP
          VIRT - everything in-use and/or reserved (all quadrants)

       Note: Even though program images and shared libraries are considered private to a process,
       they will be accounted for as shared (SHR) by the kernel.

1. COMMAND-LINE Options

       The command-line syntax for top consists of:

         -hv|-bcEeHiOSs1 -d secs -n max -u|U user -p pids -o field -w [cols]

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

       -h | -v  :Help/Version
            Show library version and the usage prompt, then quit.

       -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 vice versa.  See the `c'
            interactive command for additional information.

       -d  :Delay-time interval as:  -d ss.t (secs.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 6d. SYSTEM Restrictions File.

       -e  :Enforce-Task-Memory-Scaling as:  -e  k | m | g | t | p
            Instructs top to force task area memory to be scaled as:
               k - kibibytes
               m - mebibytes
               g - gibibytes
               t - tebibytes
               p - pebibytes

            Later this can be changed with the `e' command toggle.

       -E  :Enforce-Summary-Memory-Scaling as:  -E  k | m | g | t | p | e
            Instructs top to force summary area memory to be scaled as:
               k - kibibytes
               m - mebibytes
               g - gibibytes
               t - tebibytes
               p - pebibytes
               e - exbibytes

            Later this can be changed with the `E' command toggle.

       -H  :Threads-mode operation
            Instructs  top  to  display  individual  threads.  Without this command-line option a
            summation of all threads in each process is shown.  Later this can  be  changed  with
            the `H' interactive command.

       -i  :Idle-process toggle
            Starts  top  with  the  last remembered `i' state reversed.  When this toggle is Off,
            tasks that have not used any CPU since the last update will not  be  displayed.   For
            additional information regarding this toggle see topic 4c. TASK AREA Commands, SIZE.

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

       -o  :Override-sort-field as:  -o fieldname
            Specifies the name of the field on which tasks will be sorted, independent of what is
            reflected  in the configuration file.  You can prepend a `+' or `-' to the field name
            to also override the sort direction.  A leading `+' will force sorting high  to  low,
            whereas a `-' will ensure a low to high ordering.

            This option exists primarily to support automated/scripted batch mode operation.

       -O  :Output-field-names
            This  option  acts  as  a form of help for the above -o option.  It will cause top to
            print each of the available field names on a separate line, then  quit.   Such  names
            are subject to NLS (National Language Support) translation.

       -p  :Monitor-PIDs mode as:  -pN1 -pN2 ...  or  -pN1,N2,N3 ...
            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.

            A  pid value of zero will be treated as the process id of the top program itself once
            it is running.

            This is a command-line option only and should you wish to return to normal operation,
            it  is not necessary to quit and restart top  --  just issue any of these interactive
            commands: `=', `u' or `U'.

            The `p', `u' and `U' command-line options are mutually exclusive.

       -s  :Secure-mode operation
            Starts top with secure  mode  forced,  even  for  root.   This  mode  is  far  better
            controlled through a system configuration file (see topic 6. FILES).

       -S  :Cumulative-time toggle
            Starts top with the last remembered `S' state reversed.  When Cumulative time 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.

       -u | -U  :User-filter-mode as:  -u | -U number or name
            Display  only  processes  with  a user id or user name matching that given.  The `-u'
            option matches on  effective user whereas the `-U' option matches on any user  (real,
            effective, saved, or filesystem).

            Prepending an exclamation point (`!') to the user id or name instructs top to display
            only processes with users not matching the one provided.

            The `p', `u' and `U' command-line options are mutually exclusive.

       -w  :Output-width-override as:  -w [ number ]
            In Batch mode, when used without  an  argument  top  will  format  output  using  the
            COLUMNS= and LINES= environment variables, if set.  Otherwise, width will be fixed at
            the maximum 512 columns.   With  an  argument,  output  width  can  be  decreased  or
            increased (up to 512) but the number of rows is considered unlimited.

            In  normal  display  mode,  when  used without an argument top will attempt to format
            output using the  COLUMNS=  and  LINES=  environment  variables,  if  set.   With  an
            argument,  output  width  can  only  be  decreased,  not  increased.   Whether  using
            environment variables or an argument with -w, when not in Batch mode actual  terminal
            dimensions can never be exceeded.

            Note:  Without  the  use of this command-line option, output width is always based on
            the terminal at which top was invoked whether or not in Batch mode.

       -1  :Single/Separate-Cpu-States toggle
            Starts top with the last remembered Cpu States portion of the summary area  reversed.
            Either  all  cpu  information  will be displayed in a single line or each cpu will be
            displayed separately, depending on the state of the NUMA Node command toggle ('2').

            See the `1' and '2' interactive commands for additional information.

2. SUMMARY Display

       Each of the following  three  areas  are  individually  controlled  through  one  or  more
       interactive  commands.   See  topic  4b.  SUMMARY AREA Commands for additional information
       regarding these provisions.

   2a. UPTIME and LOAD Averages
       This portion consists of a single line containing:
           program or window name, depending on display mode
           current time and length of time since last boot
           total number of users
           system load avg over the last 1, 5 and 15 minutes

   2b. TASK and CPU States
       This portion consists of a minimum of two lines.  In an SMP environment, additional  lines
       can reflect individual CPU state percentages.

       Line  1  shows  total tasks or threads, depending on the state of the Threads-mode toggle.
       That total is further classified as:
           running; sleeping; stopped; zombie

       Line 2 shows CPU state percentages based on the interval since the last refresh.

       As a default, percentages for these individual categories are displayed.  Where two labels
       are shown below, those for more recent kernel versions are shown first.
           us, user    : time running un-niced user processes
           sy, system  : time running kernel processes
           ni, nice    : time running niced user processes
           id, idle    : time spent in the kernel idle handler
           wa, IO-wait : time waiting for I/O completion
           hi : time spent servicing hardware interrupts
           si : time spent servicing software interrupts
           st : time stolen from this vm by the hypervisor

       In  the  alternate  cpu  states  display  modes,  beyond  the first tasks/threads line, an
       abbreviated summary is shown consisting of these elements:
                      a    b     c    d
           %Cpu(s):  75.0/25.0  100[ ...

       Where: a) is the `user' (us +  ni)  percentage;  b)  is  the  `system'  (sy  +  hi  +  si)
       percentage;  c) is the total; and d) is one of two visual graphs of those representations.
       See topic 4b. SUMMARY AREA Commands and the `t' command for additional information on that
       special 4-way toggle.

   2c. MEMORY Usage
       This  portion  consists  of  two lines which may express values in kibibytes (KiB) through
       exbibytes (EiB) depending on the scaling factor enforced with the `E' interactive command.

       As a default, Line 1 reflects physical memory, classified as:
           total, free, used and buff/cache

       Line 2 reflects mostly virtual memory, classified as:
           total, free, used and avail (which is physical memory)

       The avail number on line 2 is an estimation of physical memory available for starting  new
       applications, without swapping.  Unlike the free field, it attempts to account for readily
       reclaimable page cache and memory slabs.  It is available on  kernels  3.14,  emulated  on
       kernels 2.6.27+, otherwise the same as free.

       In  the alternate memory display modes, two abbreviated summary lines are shown consisting
       of these elements:
                      a    b          c
           GiB Mem : 18.7/15.738   [ ...
           GiB Swap:  0.0/7.999    [ ...

       Where: a) is the percentage used; b) is the total available; and c) is one of  two  visual
       graphs of those representations.

       In  the  case  of physical memory, the percentage represents the total minus the estimated
       avail noted above.  The `Mem' graph itself is  divided  between  used  and  any  remaining
       memory  not otherwise accounted for by avail.  See topic 4b. SUMMARY AREA Commands and the
       `m' command for additional information on that special 4-way toggle.

       This table may help in interpreting the scaled values displayed:
           KiB = kibibyte = 1024 bytes
           MiB = mebibyte = 1024 KiB = 1,048,576 bytes
           GiB = gibibyte = 1024 MiB = 1,073,741,824 bytes
           TiB = tebibyte = 1024 GiB = 1,099,511,627,776 bytes
           PiB = pebibyte = 1024 TiB = 1,125,899,906,842,624 bytes
           EiB = exbibyte = 1024 PiB = 1,152,921,504,606,846,976 bytes

3. FIELDS / Columns

   3a. DESCRIPTIONS of Fields
       Listed below are top's available process fields (columns).  They are shown in strict ascii
       alphabetical  order.   You  may  customize  their  position  and  whether  or not they are
       displayable with the `f' or `F' (Fields Management) interactive commands.

       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 4c. TASK
       AREA Commands, SORTING.

       The fields related to physical memory or virtual memory reference  `(KiB)'  which  is  the
       unsuffixed  display mode.  Such fields may, however, be scaled from KiB through PiB.  That
       scaling is influenced via the `e' interactive command or established for startup through a
       build option.

        1. %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 a process is multi-threaded and top is not operating  in
           Threads mode, amounts greater than 100% may be reported.  You toggle Threads mode with
           the `H' interactive command.

           Also for multi-processor environments, 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.

           Note: When running in forest view mode (`V') with children collapsed (`v'), this field
           will  also  include  the  CPU  time of those unseen children.  See topic 4c. TASK AREA
           Commands, CONTENT for more information regarding the `V' and `v' toggles.

        2. %MEM  --  Memory Usage (RES)
           A task's currently resident share of available physical memory.

           See `OVERVIEW, Linux Memory Types' for additional details.

        3. CGNAME  --  Control Group Name
           The name of the control group to which a process belongs, or `-' if not applicable for
           that process.

           This  will  typically  be  the  last entry in the full list of control groups as shown
           under the next heading (CGROUPS).  And as is true there, this field is  also  variable
           width.

        4. CGROUPS  --  Control Groups
           The names of the control group(s) to which a process belongs, or `-' if not applicable
           for that process.

           Control Groups provide for allocating resources (cpu, memory, network bandwidth, etc.)
           among installation-defined groups of processes.  They enable fine-grained control over
           allocating, denying, prioritizing, managing and monitoring those resources.

           Many different hierarchies of cgroups can exist simultaneously on a  system  and  each
           hierarchy  is  attached  to  one  or more subsystems.  A subsystem represents a single
           resource.

           Note: The CGROUPS field, unlike most columns, is not fixed-width.  When displayed,  it
           plus any other variable width columns will be allocated all remaining screen width (up
           to the maximum 512 characters).  Even so,  such  variable  width  fields  could  still
           suffer  truncation.   See  topic  5c. SCROLLING a Window for additional information on
           accessing any truncated data.

        5. CODE  --  Code Size (KiB)
           The amount of physical memory currently devoted to executable code, also known as  the
           Text Resident Set size or TRS.

           See `OVERVIEW, Linux Memory Types' for additional details.

        6. COMMAND  --  Command Name or Command Line
           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  brackets,  as  in  this
           example:
               [kthreadd]

           This  field  may  also  be  impacted  by  the  forest  view display mode.  See the `V'
           interactive command for additional information regarding that mode.

           Note: The COMMAND field, unlike most columns, is not fixed-width.  When displayed,  it
           plus any other variable width columns will be allocated all remaining screen width (up
           to the maximum 512 characters).  Even so,  such  variable  width  fields  could  still
           suffer  truncation.   This  is  especially  true for this field when command lines are
           being displayed (the `c' interactive command.)  See topic 5c. SCROLLING a  Window  for
           additional information on accessing any truncated data.

        7. DATA  --  Data + Stack Size (KiB)
           The  amount  of  private  memory  reserved by a process.  It is also known as the Data
           Resident Set or DRS.  Such memory may not yet be mapped to physical memory  (RES)  but
           will always be included in the virtual memory (VIRT) amount.

           See `OVERVIEW, Linux Memory Types' for additional details.

        8. ENVIRON  --  Environment variables
           Display all of the environment variables, if any, as seen by the respective processes.
           These variables will be displayed in their raw native order, not the sorted order  you
           are accustomed to seeing with an unqualified `set'.

           Note:  The ENVIRON field, unlike most columns, is not fixed-width.  When displayed, it
           plus any other variable width columns will be allocated all remaining screen width (up
           to  the  maximum  512  characters).   Even  so, such variable width fields could still
           suffer truncation.  This is especially true for this field.  See topic 5c. SCROLLING a
           Window for additional information on accessing any truncated data.

        9. 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>.

       10. GID  --  Group Id
           The effective group ID.

       11. GROUP  --  Group Name
           The effective group name.

       12. LXC  --  Lxc Container Name
           The  name  of  the  lxc container within which a task is running.  If a process is not
           running inside a container, a dash (`-') will be shown.

       13. 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 dispatch-ability.

       14. NU  --  Last known NUMA node
           A number representing the NUMA node associated with the  last  used  processor  (`P').
           When -1 is displayed it means that NUMA information is not available.

           See the `'2' and `3' interactive commands for additional NUMA provisions affecting the
           summary area.

       15. OOMa  --  Out of Memory Adjustment Factor
           The value, ranging from -1000 to +1000, added to  the  current  out  of  memory  score
           (OOMs) which is then used to determine which task to kill when memory is exhausted.

       16. OOMs  --  Out of Memory Score
           The  value,  ranging  from  0  to +1000, used to select task(s) to kill when memory is
           exhausted.  Zero translates to `never kill' whereas 1000 means `always kill'.

       17. 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).

       18. PGRP  --  Process Group Id
           Every  process  is  member of a unique process group which is used for distribution of
           signals and by terminals to arbitrate requests for their input  and  output.   When  a
           process  is  created (forked), it becomes a member of the process group of its parent.
           By convention, this value equals the process ID (see PID) of the  first  member  of  a
           process group, called the process group leader.

       19. PID  --  Process Id
           The  task's  unique  process  ID, which periodically wraps, though never restarting at
           zero.  In kernel terms, it is a dispatchable entity defined by a task_struct.

           This value may also be used as: a process group ID (see PGRP); a session  ID  for  the
           session  leader  (see  SID); a thread group ID for the thread group leader (see TGID);
           and a TTY process group ID for the process group leader (see TPGID).

       20. PPID  --  Parent Process Id
           The process ID (pid) of a task's parent.

       21. PR  --  Priority
           The scheduling priority of the task.  If you see `rt' in this field, it means the task
           is running under real time scheduling priority.

           Under  linux,  real  time  priority  is  somewhat  misleading  since traditionally the
           operating itself was not preemptible.  And while the 2.6 kernel  can  be  made  mostly
           preemptible, it is not always so.

       22. RES  --  Resident Memory Size (KiB)
           A  subset  of  the  virtual address space (VIRT) representing the non-swapped physical
           memory a task is currently using.  It is also the sum  of  the  RSan,  RSfd  and  RSsh
           fields.

           It  can  include  private  anonymous  pages,  private pages mapped to files (including
           program images and shared libraries) plus shared anonymous pages.  All such memory  is
           backed by the swap file represented separately under SWAP.

           Lastly, this field may also include shared file-backed pages which, when modified, act
           as a dedicated swap file and thus will never impact SWAP.

           See `OVERVIEW, Linux Memory Types' for additional details.

       23. RSan  --  Resident Anonymous Memory Size (KiB)
           A subset of resident memory (RES) representing private pages not mapped to a file.

       24. RSfd  --  Resident File-Backed Memory Size (KiB)
           A subset of resident memory (RES) representing the implicitly shared pages  supporting
           program  images  and  shared libraries.  It also includes explicit file mappings, both
           private and shared.

       25. RSlk  --  Resident Locked Memory Size (KiB)
           A subset of resident memory (RES) which cannot be swapped out.

       26. RSsh  --  Resident Shared Memory Size (KiB)
           A subset of  resident  memory  (RES)  representing  the  explicitly  shared  anonymous
           shm*/mmap pages.

       27. RUID  --  Real User Id
           The real user ID.

       28. RUSER  --  Real User Name
           The real user name.

       29. S  --  Process Status
           The status of the task which can be one of:
               D = uninterruptible sleep
               I = idle
               R = running
               S = sleeping
               T = stopped by job control signal
               t = stopped by debugger during trace
               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.

       30. SHR  --  Shared Memory Size (KiB)
           A subset of resident memory (RES) that may  be  used  by  other  processes.   It  will
           include shared anonymous pages and shared file-backed pages.  It also includes private
           pages mapped to files representing program images and shared libraries.

           See `OVERVIEW, Linux Memory Types' for additional details.

       31. SID  --  Session Id
           A session is a collection of process groups (see PGRP),  usually  established  by  the
           login shell.  A newly forked process joins the session of its creator.  By convention,
           this value equals the process ID (see PID) of the first member of the session,  called
           the session leader, which is usually the login shell.

       32. SUID  --  Saved User Id
           The saved user ID.

       33. SUPGIDS  --  Supplementary Group IDs
           The  IDs of any supplementary group(s) established at login or inherited from a task's
           parent.  They are displayed in a comma delimited list.

           Note: The SUPGIDS field, unlike most columns, is not fixed-width.  When displayed,  it
           plus any other variable width columns will be allocated all remaining screen width (up
           to the maximum 512 characters).  Even so,  such  variable  width  fields  could  still
           suffer  truncation.   See  topic  5c. SCROLLING a Window for additional information on
           accessing any truncated data.

       34. SUPGRPS  --  Supplementary Group Names
           The names of any supplementary group(s) established  at  login  or  inherited  from  a
           task's parent.  They are displayed in a comma delimited list.

           Note:  The SUPGRPS field, unlike most columns, is not fixed-width.  When displayed, it
           plus any other variable width columns will be allocated all remaining screen width (up
           to  the  maximum  512  characters).   Even  so, such variable width fields could still
           suffer truncation.  See topic 5c. SCROLLING a Window  for  additional  information  on
           accessing any truncated data.

       35. SUSER  --  Saved User Name
           The saved user name.

       36. SWAP  --  Swapped Size (KiB)
           The  formerly resident portion of a task's address space written to the swap file when
           physical memory becomes over committed.

           See `OVERVIEW, Linux Memory Types' for additional details.

       37. TGID  --  Thread Group Id
           The ID of the thread group to which a task belongs.  It is the PID of the thread group
           leader.  In kernel terms, it represents those tasks that share an mm_struct.

       38. 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  have  used.   You
           toggle  Cumulative  mode  with  `S',  which  is  both  a  command-line  option  and an
           interactive command.  See the  `S'  interactive  command  for  additional  information
           regarding this mode.

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

       40. TPGID  --  Tty Process Group Id
           The  process  group  ID  of  the  foreground process for the connected tty, or -1 if a
           process is not connected to a terminal.  By convention, this value equals the  process
           ID (see PID) of the process group leader (see PGRP).

       41. 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.

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

       43. USED  --  Memory in Use (KiB)
           This field represents the non-swapped physical memory a task is using (RES)  plus  the
           swapped out portion of its address space (SWAP).

           See `OVERVIEW, Linux Memory Types' for additional details.

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

       45. VIRT  --  Virtual Memory Size (KiB)
           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.

           See `OVERVIEW, Linux Memory Types' for additional details.

       46. WCHAN  --  Sleeping in Function
           This  field  will  show the name of the kernel function in which the task is currently
           sleeping.  Running tasks will display a dash (`-') in this column.

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

           This field was deprecated with linux 2.6 and is always zero.

       48. nMaj  --  Major 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 auxiliary storage access  is
           involved in making that page available.

       49. nMin  --  Minor Page Fault count
           The  number  of  minor 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 minor page fault does not involve auxiliary storage
           access in making that page available.

       50. nTH  --  Number of Threads
           The number of threads associated with a process.

       51. nsIPC  --  IPC namespace
           The Inode of the namespace used to isolate interprocess communication (IPC)  resources
           such as System V IPC objects and POSIX message queues.

       52. nsMNT  --  MNT namespace
           The  Inode  of  the  namespace  used  to isolate filesystem mount points thus offering
           different views of the filesystem hierarchy.

       53. nsNET  --  NET namespace
           The Inode of the namespace used to isolate  resources  such  as  network  devices,  IP
           addresses, IP routing, port numbers, etc.

       54. nsPID  --  PID namespace
           The  Inode  of  the namespace used to isolate process ID numbers meaning they need not
           remain unique.  Thus, each such namespace could have its own `init/systemd'  (PID  #1)
           to manage various initialization tasks and reap orphaned child processes.

       55. nsUSER  --  USER namespace
           The  Inode  of  the  namespace used to isolate the user and group ID numbers.  Thus, a
           process could have a normal unprivileged user ID outside a user namespace while having
           a user ID of 0, with full root privileges, inside that namespace.

       56. nsUTS  --  UTS namespace
           The  Inode  of the namespace used to isolate hostname and NIS domain name.  UTS simply
           means "UNIX Time-sharing System".

       57. vMj  --  Major Page Fault Count Delta
           The number of major page faults that have occurred since the last update (see nMaj).

       58. vMn  --  Minor Page Fault Count Delta
           The number of minor page faults that have occurred since the last update (see nMin).

   3b. MANAGING Fields
       After pressing the interactive  command  `f'  or  `F'  (Fields  Management)  you  will  be
       presented  with  a  screen  showing:  1) the `current' window name; 2) the designated sort
       field; 3) all fields in their current order along with descriptions.  Entries marked  with
       an asterisk are the currently displayed fields, screen width permitting.

           ·  As  the  on screen instructions indicate, you navigate among the fields with the Up
              and Down arrow keys.  The PgUp, PgDn, Home and End keys can also be used to quickly
              reach the first or last available field.

           ·  The Right arrow key selects a field for repositioning and the Left arrow key or the
              <Enter> key commits that field's placement.

           ·  The `d' key or the <Space> bar toggles a  field's  display  status,  and  thus  the
              presence or absence of the asterisk.

           ·  The  `s'  key  designates  a  field  as  the  sort  field.  See topic 4c. TASK AREA
              Commands, SORTING for additional information regarding your  selection  of  a  sort
              field.

           ·  The `a' and `w' keys can be used to cycle through all available windows and the `q'
              or <Esc> keys exit Fields Management.

       The Fields Management 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
       <Esc> was pressed will be made current as you return to the top  display.   See  topic  5.
       ALTERNATE-DISPLAY  Provisions  and  the `g' interactive command for insight into `current'
       windows and field groups.

       Note: Any window that has been scrolled horizontally will be reset if  any  field  changes
       are  made via the Fields Management screen.  Any vertical scrolled position, however, will
       not be affected.  See topic 5c. SCROLLING a Window for  additional  information  regarding
       vertical and horizontal scrolling.

4. 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.

         4a. Global-Commands
               <Ent/Sp> ?, =, 0,
               A, B, d, E, e, g, h, H, I, k, q, r, s, W, X, Y, Z
         4b. Summary-Area-Commands
               C, l, t, m, 1, 2, 3, 4, !
         4c. Task-Area-Commands
               Appearance:  b, J, j, x, y, z
               Content:     c, f, F, o, O, S, u, U, V, v
               Size:        #, i, n
               Sorting:     <, >, f, F, R
         4d. Color-Mapping
               <Ret>, a, B, b, H, M, q, S, T, w, z, 0 - 7
         5b. Commands-for-Windows
               -, _, =, +, A, a, g, G, w
         5c. Scrolling-a-Window
               C, Up, Dn, Left, Right, PgUp, PgDn, Home, End
         5d. Searching-in-a-Window
               L, &

   4a. 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 awaken top and following receipt of any  input  the  entire  display
              will  be  repainted.   They  also force an update of any hotplugged cpu or physical
              memory changes.

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

          ? | 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-Display-Limits
              Removes  restrictions  on  what  is shown.  This command will reverse any `i' (idle
              tasks), `n' (max tasks) and `v' (hide children) commands that might be active.   It
              also  provides  for  an  exit from PID monitoring, User filtering, Other filtering,
              Locate processing and Combine Cpus mode.

              Additionally, if the window has been scrolled it will be reset with this command.

          0  :Zero-Suppress toggle
              This command determines whether zeros are shown  or  suppressed  for  many  of  the
              fields  in  a  task  window.  Fields like UID, GID, NI, PR or P are not affected by
              this toggle.

          A  :Alternate-Display-Mode toggle
              This command will switch between full-screen mode and alternate-display mode.   See
              topic  5.  ALTERNATE-DISPLAY Provisions 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 | 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.

          E  :Enforce-Summary-Memory-Scale in Summary Area
              With  this  command you can cycle through the available summary area memory scaling
              which ranges from  KiB  (kibibytes  or  1,024  bytes)  through  EiB  (exbibytes  or
              1,152,921,504,606,846,976 bytes).

              If  you see a `+' between a displayed number and the following label, it means that
              top was forced to truncate some portion of that number.   By  raising  the  scaling
              factor, such truncation can be avoided.

          e  :Enforce-Task-Memory-Scale in Task Area
              With  this  command  you  can  cycle through the available task area memory scaling
              which ranges from  KiB  (kibibytes  or  1,024  bytes)  through  PiB  (pebibytes  or
              1,125,899,906,842,624 bytes).

              While  top  will  try  to honor the selected target range, additional scaling might
              still be necessary in order to accommodate current values.  If you wish  to  see  a
              more  homogeneous  result  in  the  memory  columns, raising the scaling range will
              usually accomplish that goal.  Raising it too high, however, is likely  to  produce
              an all zero result which cannot be suppressed with the `0' interactive command.

          g  :Choose-Another-Window/Field-Group
              You  will be prompted to enter a number between 1 and 4 designating the 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.

          H  :Threads-mode toggle
              When  this  toggle is On, individual threads will be displayed for all processes in
              all visible task windows.  Otherwise, top displays a summation of  all  threads  in
              each process.

          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  told
              the new state of this toggle.

       *  k  :Kill-a-task
              You will be prompted for a PID and then the signal to send.

              Entering  no  PID  or a negative number will be interpreted as the default shown in
              the prompt (the first task displayed).  A PID value of zero means the  top  program
              itself.

              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, type an invalid number
                  2) at the signal prompt, type 0 (or any invalid signal)
                  3) at any prompt, type <Esc>

          q  :Quit

       *  r  :Renice-a-Task
              You will be prompted for a PID and then the value to nice it to.

              Entering  no  PID  or a negative number will be interpreted as the default shown in
              the prompt (the first task displayed).  A PID value of zero means the  top  program
              itself.

              A  positive  nice  value  will  cause  a  process  to lose priority.  Conversely, a
              negative nice value will cause a process to be viewed more favorably by the kernel.
              As  a  general  rule,  ordinary  users  can  only  increase  the nice value and are
              prevented from lowering it.

              If you wish to abort the renice process, do one of the following depending on  your
              progress:
                  1) at the pid prompt, type an invalid number
                  2) at the nice prompt, type <Enter> with no input
                  3) at any prompt, type <Esc>

          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.

          X  :Extra-Fixed-Width
              Some  fields  are  fixed  width  and  not  scalable.   As such, they are subject to
              truncation which would be indicated by a `+' in the last position.

              This interactive command can be used to alter the widths of the following fields:

                  field  default    field  default    field  default
                  GID       5       GROUP     8       WCHAN    10
                  RUID      5       LXC       8       nsIPC    10
                  SUID      5       RUSER     8       nsMNT    10
                  UID       5       SUSER     8       nsNET    10
                                    TTY       8       nsPID    10
                                    USER      8       nsUSER   10
                                                      nsUTS    10

              You will be prompted for the amount to be added to the default widths shown  above.
              Entering zero forces a return to those defaults.

              If  you enter a negative number, top will automatically increase the column size as
              needed until there is no more truncated data.  You can accelerate this  process  by
              reducing the delay interval or holding down the <Space> bar.

              Note:  Whether  explicitly  or automatically increased, the widths for these fields
              are never decreased by top.  To narrow them you must specify a  smaller  number  or
              restore the defaults.

          Y  :Inspect-Other-Output
              After  issuing  the `Y' interactive command, you will be prompted for a target PID.
              Typing a value or accepting the default results in a separate screen.  That  screen
              can be used to view a variety of files or piped command output while the normal top
              iterative display is paused.

              Note: This interactive command is only fully realized when supporting entries  have
              been  manually  added  to  the  end  of the top configuration file.  For details on
              creating those entries, see topic 6b. ADDING INSPECT Entries.

              Most of the keys used to navigate the Inspect feature are reflected in  its  header
              prologue.   There  are, however, additional keys available once you have selected a
              particular file or command.  They are familiar to anyone who  has  used  the  pager
              `less' and are summarized here for future reference.

                  key      function
                  =        alternate status-line, file or pipeline
                  /        find, equivalent to `L' locate
                  n        find next, equivalent to `&' locate next
                  <Space>  scroll down, equivalent to <PgDn>
                  b        scroll up, equivalent to <PgUp>
                  g        first line, equivalent to <Home>
                  G        last line, equivalent to <End>

          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 4d. 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.

   4b. 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  5.
       ALTERNATE-DISPLAY  Provisions  and  the `g' interactive command for insight into `current'
       windows and field groups.

          C  :Show-scroll-coordinates toggle
              Toggle an informational message which is displayed whenever the message line is not
              otherwise being used.  For additional information see topic 5c. SCROLLING a Window.

          l  :Load-Average/Uptime toggle
              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.

          t  :Task/Cpu-States toggle
              This  command  affects from 2 to many summary area lines, depending on the state of
              the `1', `2' or `3' command toggles and whether or not top is  running  under  true
              SMP.

              This  portion of the summary area is also influenced by the `H' interactive command
              toggle, as reflected in the total label which shows either Tasks or Threads.

              This command serves as a 4-way toggle, cycling through these modes:
                  1. detailed percentages by category
                  2. abbreviated user/system and total % + bar graph
                  3. abbreviated user/system and total % + block graph
                  4. turn off task and cpu states display

              When operating in either of the  graphic  modes,  the  display  becomes  much  more
              meaningful when individual CPUs or NUMA nodes are also displayed.  See the the `1',
              `2' and `3' commands below for additional information.

          m  :Memory/Swap-Usage toggle
              This command affects the two summary area lines dealing with physical  and  virtual
              memory.

              This command serves as a 4-way toggle, cycling through these modes:
                  1. detailed percentages by memory type
                  2. abbreviated % used/total available + bar graph
                  3. abbreviated % used/total available + block graph
                  4. turn off memory display

          1  :Single/Separate-Cpu-States toggle
              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, ...'  up to available screen height.

          2  :NUMA-Nodes/Cpu-Summary toggle
              This  command  toggles  between  the  `1'  command  cpu summary display (only) or a
              summary display plus the cpu usage statistics for  each  NUMA  Node.   It  is  only
              available if a system has the requisite NUMA support.

          3  :Expand-NUMA-Node
              You will be invited to enter a number representing a NUMA Node.  Thereafter, a node
              summary plus the statistics for each cpu in that node will be shown until the  `1',
              `2'  or  `4' command toggle is pressed.  This interactive command is only available
              if a system has the requisite NUMA support.

          4  :Display-Cpus-Two-Abreast
              This command turns the `1' toggle Off for individual cpu  display  but  prints  the
              results  two  abreast.   It requires a terminal with a minimum width of 80 columns.
              If a terminal's width is decreased below the minimum  while  top  is  running,  top
              reverts to the normal `1' toggle Off state.

              To  avoid  truncation  when  displaying  detailed  cpu statistcs, as opposed to the
              graphic representations, a minimum width of 165 columns would be required.

          !  :Combine-Cpus-Mode
              This command toggle is intended for massively parallel SMP environments where, even
              with  the `4' command toggle, not all processors can be displayed.  With each press
              of `!' the number of additional cpu's combined is doubled thus reducing  the  total
              number of cpu lines displayed.

              For  example,  with  the first press of `!' one additional cpu will be combined and
              displayed as `0-1, 2-3, ...' instead of the normal  `%Cpu0,  %Cpu1,  %Cpu2,  %Cpu3,
              ...'.   With a second `!' command toggle two additional cpus are combined and shown
              as `0-2, 3-5, ...'.  Then the third '!'  press,  combining  four  additional  cpus,
              shows as `0-4, 5-9, ...', etc.

              Such  progression  continues  until individual cpus are again displayed and impacts
              both the `1' and `4' toggles (one or two columns).  Use the  `='  command  to  exit
              Combine Cpus mode.

       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.

   4c. 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 5. ALTERNATE-DISPLAY
       Provisions).

       APPEARANCE of task window

          J  :Justify-Numeric-Columns toggle
              Alternates between right-justified (the default) and left-justified  numeric  data.
              If  the numeric data completely fills the available column, this command toggle may
              impact the column header only.

          j  :Justify-Character-Columns toggle
              Alternates between left-justified (the default) and right-justified character data.
              If  the  character  data completely fills the available column, this command toggle
              may impact the column header only.

         The following commands will also be influenced by the state  of  the  global  `B'  (bold
         enable) toggle.

          b  :Bold/Reverse toggle
              This  command  will  impact how the `x' and `y' toggles are displayed.  It may also
              impact the summary area when a bar graph has been selected for cpu states or memory
              usage via the `t' or `m' toggles.

          x  :Column-Highlight toggle
              Changes  highlighting  for  the  current  sort field.  If you forget which field is
              being sorted this command can serve as a quick visual reminder, providing the  sort
              field is being displayed.  The sort field might not be visible because:
                  1) there is insufficient Screen Width
                  2) the `f' interactive command turned it Off

              Note:  Whenever  Searching  and/or  Other  Filtering  is active in a window, column
              highlighting is temporarily disabled.  See the notes  at  the  end  of  topics  5d.
              SEARCHING and 5e. FILTERING for an explanation why.

          y  :Row-Highlight toggle
              Changes  highlighting  for  "running" tasks.  For additional insight into this task
              state, see topic 3a. DESCRIPTIONS of Fields, the `S' field (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 | F  :Fields-Management
              These  keys  display  a  separate  screen  where  you  can  change which fields are
              displayed,  their  order  and  also  designate  the  sort  field.   For  additional
              information on these interactive commands see topic 3b. MANAGING Fields.

          o | O  :Other-Filtering
              You  will  be prompted for the selection criteria which then determines which tasks
              will be shown in the `current' window.  Your criteria can be made case sensitive or
              case  can  be ignored.  And you determine if top should include or exclude matching
              tasks.

              See topic 5e. FILTERING in a window for details on  these  and  additional  related
              interactive commands.

          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 | U  :Show-Specific-User-Only
              You  will  be  prompted  for the uid or name of the user to display.  The -u option
              matches on  effective user whereas  the  -U  option  matches  on  any  user  (real,
              effective, saved, or filesystem).

              Thereafter,  in  that task window only matching users will be shown, or possibly no
              processes will be shown.  Prepending an exclamation point (`!') to the user  id  or
              name  instructs  top  to  display  only  processes  with users not matching the one
              provided.

              Different task windows can be used to filter different users.  Later, if  you  wish
              to  monitor all users again in the `current' window, re-issue this command but just
              press <Enter> at the prompt.

          V  :Forest-View-Mode toggle
              In this mode, processes are reordered according to their parents and the layout  of
              the  COMMAND  column  resembles  that  of  a tree.  In forest view mode it is still
              possible to toggle between program name and command line (see the  `c'  interactive
              command) or between processes and threads (see the `H' interactive command).

              Note:  Typing  any  key  affecting the sort order will exit forest view mode in the
              `current' window.  See topic 4c. TASK AREA Commands,  SORTING  for  information  on
              those keys.

          v  :Hide/Show-Children toggle
              When  in  forest  view  mode, this key serves as a toggle to collapse or expand the
              children of a parent.

              The toggle is applied against the first (topmost) process in the `current'  window.
              See  topic  5c.  SCROLLING  a  Window for additional information regarding vertical
              scrolling.

              If the target process has not forked any children, this key has no effect.  It also
              has no effect when not in forest view mode.

       SIZE of task window

          i  :Idle-Process toggle
              Displays  all tasks or just active tasks.  When this toggle is Off, tasks that have
              not used any CPU since the last update will not be displayed.  However, due to  the
              granularity  of  the  %CPU  and TIME+ fields, some processes may still be displayed
              that appear to have used no CPU.

              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 | #  :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 | F  :Fields-Management
                 These keys display a separate screen where you can change which field is used as
                 the sort column, among other functions.  This 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.

   4d. 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.

       The following interactive commands are available.
           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 you 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.

5. ALTERNATE-DISPLAY Provisions

   5a. 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.

   5b. COMMANDS for Windows
          - | _  :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'
              interactive command.  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.

       *  = | +  :Equalize/Reset-Window(s)
              The `=' key forces the `current' window's task display  to  be  visible.   It  also
              reverses  any  active `i' (idle tasks), `n' (max tasks), `u/U' (user filter), `o/O'
              (other filter), `v' (hide children), `L' (locate) and `!' (combine cpus)  commands.
              Also,  if  the  window  had been scrolled, it will be reset with this command.  See
              topic 5c. SCROLLING a Window for  additional  information  regarding  vertical  and
              horizontal scrolling.

              The  `+'  key does the same for all windows.  The four task displays will reappear,
              evenly balanced, while retaining any customizations previously applied beyond those
              noted for the `=' command toggle.

       *  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 | 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 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 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 with color mapping
                         and fields management

   5c. SCROLLING a Window
       Typically a task window is a partial view into a systems's total tasks/threads which shows
       only  some  of the available fields/columns.  With these scrolling keys, you can move that
       view vertically or horizontally to reveal any desired task or column.

       Up,PgUp  :Scroll-Tasks
           Move the view up toward the first task row, until the first task is displayed  at  the
           top  of the `current' window.  The Up arrow key moves a single line while PgUp scrolls
           the entire window.

       Down,PgDn  :Scroll-Tasks
           Move the view down toward the last task row, until the last  task  is  the  only  task
           displayed  at the top of the `current' window.  The Down arrow key moves a single line
           while PgDn scrolls the entire window.

       Left,Right  :Scroll-Columns
           Move the view of displayable fields horizontally one column at a time.

           Note: As a reminder,  some  fields/columns  are  not  fixed-width  but  allocated  all
           remaining  screen  width when visible.  When scrolling right or left, that feature may
           produce some unexpected results initially.

           Additionally,  there  are  special  provisions  for  any  variable  width  field  when
           positioned  as  the  last  displayed  field.  Once that field is reached via the right
           arrow key, and is thus the only column shown, you can continue scrolling  horizontally
           within   such  a  field.   See  the  `C'  interactive  command  below  for  additional
           information.

       Home  :Jump-to-Home-Position
           Reposition the display to the un-scrolled coordinates.

       End  :Jump-to-End-Position
           Reposition the display so that the rightmost  column  reflects  the  last  displayable
           field and the bottom task row represents the last task.

           Note: From this position it is still possible to scroll down and right using the arrow
           keys.  This is true until a single column and a  single  task  is  left  as  the  only
           display element.

       C  :Show-scroll-coordinates toggle
           Toggle  an  informational  message which is displayed whenever the message line is not
           otherwise being used.  That message will take one of two forms depending on whether or
           not a variable width column has also been scrolled.

             scroll coordinates: y = n/n (tasks), x = n/n (fields)
             scroll coordinates: y = n/n (tasks), x = n/n (fields) + nn

           The  coordinates  shown  as n/n are relative to the upper left corner of the `current'
           window.  The additional `+ nn' represents  the  displacement  into  a  variable  width
           column  when  it has been scrolled horizontally.  Such displacement occurs in normal 8
           character tab stop amounts via the right and left arrow keys.

           y = n/n (tasks)
               The first n represents the topmost visible task and  is  controlled  by  scrolling
               keys.  The second n is updated automatically to reflect total tasks.

           x = n/n (fields)
               The  first  n  represents  the  leftmost  displayed  column  and  is controlled by
               scrolling keys.  The second n is the total number of  displayable  fields  and  is
               established with the `f' interactive command.

       The  above  interactive  commands  are  always  available  in  full-screen  mode but never
       available in alternate-display mode if  the  `current'  window's  task  display  has  been
       toggled Off.

       Note:  When  any  form of filtering is active, you can expect some slight aberrations when
       scrolling since not all tasks will be visible.  This is particularly apparent  when  using
       the Up/Down arrow keys.

   5d. SEARCHING in a Window
       You can use these interactive commands to locate a task row containing a particular value.

       L  :Locate-a-string
           You will be prompted for the case-sensitive string to locate starting from the current
           window coordinates.  There are no restrictions on search string content.

           Searches are not limited to values from a single field or column.  All of  the  values
           displayed  in  a  task  row  are  allowed in a search string.  You may include spaces,
           numbers, symbols and even forest view artwork.

           Keying <Enter> with no input will effectively disable the `&' key until a  new  search
           string is entered.

       &  :Locate-next
           Assuming  a  search  string  has been established, top will attempt to locate the next
           occurrence.

       When a match is found, the current window is  repositioned  vertically  so  the  task  row
       containing  that string is first.  The scroll coordinates message can provide confirmation
       of such vertical repositioning (see the `C' interactive command).   Horizontal  scrolling,
       however, is never altered via searching.

       The availability of a matching string will be influenced by the following factors.

          a. Which fields are displayable from the total available,
             see topic 3b. MANAGING Fields.

          b. Scrolling a window vertically and/or horizontally,
             see topic 5c. SCROLLING a Window.

          c. The state of the command/command-line toggle,
             see the `c' interactive command.

          d. The stability of the chosen sort column,
             for example PID is good but %CPU bad.

       If  a  search  fails, restoring the `current' window home (unscrolled) position, scrolling
       horizontally, displaying command-lines or choosing a more  stable  sort  field  could  yet
       produce a successful `&' search.

       The  above  interactive  commands  are  always  available  in  full-screen  mode but never
       available in alternate-display mode if  the  `current'  window's  task  display  has  been
       toggled Off.

       Note:  Whenever  a  Search is active in a window, top will turn column highlighting Off to
       prevent false matches on internal non-display escape sequences.  Such highlighting will be
       restored  when  a  window's  search  string is empty.  See the `x' interactive command for
       additional information on sort column highlighting.

   5e. FILTERING in a Window
       You can use this `Other Filter' feature to establish selection criteria  which  will  then
       determine  which  tasks  are  shown  in  the  `current'  window.  Such filters can be made
       presistent if preserved in the rcfile via the 'W' interactive command.

       Establishing a filter requires: 1) a field name; 2) an operator; and 3) a selection value,
       as a minimum.  This is the most complex of top's user input requirements so, when you make
       a mistake, command recall will be your friend.  Remember the Up/Down arrow keys  or  their
       aliases when prompted for input.

       Filter Basics

          1. field names are case sensitive and spelled as in the header

          2. selection values need not comprise the full displayed field

          3. a selection is either case insensitive or sensitive to case

          4. the default is inclusion, prepending `!' denotes exclusions

          5. multiple selection criteria can be applied to a task window

          6. inclusion and exclusion criteria can be used simultaneously

          7. the 1 equality and 2 relational filters can be freely mixed

          8. separate unique filters are maintained for each task window

          If  a  field is not turned on or is not currently in view, then your selection criteria
          will not affect the display.  Later,  should  a  filtered  field  become  visible,  the
          selection criteria will then be applied.

       Keyboard Summary

         o  :Other-Filter (lower case)
             You will be prompted to establish a filter that ignores case when matching.

         O  :Other-Filter (upper case)
             You will be prompted to establish a case sensitive filter.

        ^O  :Show-Active-Filters (Ctrl key + `o')
             This can serve as a reminder of which filters are active in the `current' window.  A
             summary will be shown on the message line until you press the <Enter> key.

         =  :Reset-Filtering in current window
             This clears all of your selection criteria in the `current'  window.   It  also  has
             additional impact so please see topic 4a. GLOBAL Commands.

         +  :Reset-Filtering in all windows
             This   clears   the   selection  criteria  in  all  windows,  assuming  you  are  in
             alternate-display mode.  As with the `=' interactive command, it too has  additional
             consequences so you might wish to see topic 5b. COMMANDS for Windows.

       Input Requirements

          When  prompted for selection criteria, the data you provide must take one of two forms.
          There are 3 required pieces of information, with a 4th as optional.  These examples use
          spaces for clarity but your input generally would not.
                  #1           #2  #3              ( required )
                  Field-Name   ?   include-if-value
               !  Field-Name   ?   exclude-if-value
               #4                                  ( optional )

          Items  #1,  #3  and  #4 should be self-explanatory.  Item #2 represents both a required
          delimiter and the operator which must be one of either equality (`=') or relation  (`<'
          or `>').

          The  `='  equality  operator  requires  only  a  partial match and that can reduce your
          `if-value' input requirements.  The `>'  or  `<'  relational  operators  always  employ
          string comparisons, even with numeric fields.  They are designed to work with a field's
          default justification and with homogeneous data.  When  some  field's  numeric  amounts
          have  been  subjected  to  scaling  while  others  have  not,  that  data  is no longer
          homogeneous.

          If you establish a relational filter and  you  have  changed  the  default  Numeric  or
          Character  justification,  that  filter is likely to fail.  When a relational filter is
          applied to a memory field and  you  have  not  changed  the  scaling,  it  may  produce
          misleading  results.   This  happens,  for example, because `100.0m' (MiB) would appear
          greater than `1.000g' (GiB) when compared as strings.

          If your filtered results appear suspect, simply altering justification or  scaling  may
          yet  achieve  the desired objective.  See the `j', `J' and `e' interactive commands for
          additional information.

       Potential Problems

          These GROUP filters could produce the exact same results or the second  one  might  not
          display anything at all, just a blank task window.
               GROUP=root        ( only the same results when )
               GROUP=ROOT        ( invoked via lower case `o' )

          Either  of  these  RES  filters  might  yield  inconsistent  and/or misleading results,
          depending on the current memory scaling factor.  Or  both  filters  could  produce  the
          exact same results.
               RES>9999          ( only the same results when )
               !RES<10000        ( memory scaling is at `KiB' )

          This  nMin  filter  illustrates  a  problem unique to scalable fields.  This particular
          field can display a maximum of 4 digits, beyond which values are  automatically  scaled
          to  KiB  or above.  So while amounts greater than 9999 exist, they will appear as 2.6m,
          197k, etc.
               nMin>9999         ( always a blank task window )

       Potential Solutions

          These examples illustrate how Other Filtering can  be  creatively  applied  to  achieve
          almost  any  desired  result.   Single quotes are sometimes shown to delimit the spaces
          which are part of a filter or to represent a request for status (^O)  accurately.   But
          if you used them with if-values in real life, no matches would be found.

          Assuming  field  nTH  is displayed, the first filter will result in only multi-threaded
          processes being shown.  It also reminds us that a  trailing  space  is  part  of  every
          displayed field.  The second filter achieves the exact same results with less typing.
               !nTH=` 1 '                ( ' for clarity only )
               nTH>1                     ( same with less i/p )

          With  Forest  View  mode active and the COMMAND column in view, this filter effectively
          collapses child processes so that just 3 levels are shown.
               !COMMAND=`       `- '     ( ' for clarity only )

          The final two filters appear as in  response  to  the  status  request  key  (^O).   In
          reality,  each filter would have required separate input.  The PR example shows the two
          concurrent filters necessary to display tasks with priorities of 20 or more, since some
          might  be  negative.   Then  by  exploiting trailing spaces, the nMin series of filters
          could achieve the failed `9999' objective discussed above.
               `PR>20' + `!PR=-'         ( 2 for right result )
               `!nMin=0 ' + `!nMin=1 ' + `!nMin=2 ' + `!nMin=3 ' ...

       Note: Whenever Other Filtering is active in a window, top will  turn  column  highlighting
       Off  to prevent false matches on internal non-display escape sequences.  Such highlighting
       will be restored when a window is no longer subject to filtering.  See the `x' interactive
       command for additional information on sort column highlighting.

6. FILES

   6a. PERSONAL Configuration File
       This file is created or updated via the 'W' interactive command.

       The legacy version is written as `$HOME/.your-name-4-top' + `rc' with a leading period.

       A  newly created configuration file is written as procps/your-name-4-top' + `rc' without a
       leading period.  The procps directory will be subordinate to either $XDG_CONFIG_HOME  when
       set as an absolute path or the $HOME/.config directory.

       While not intended to be edited manually, 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,etc
             "      # line  c: summclr,msgsclr,headclr,taskclr
           global   # line 15: additional miscellaneous settings
             "      # any remaining lines are devoted to optional
             "      # active 'other filters' discussed in section 5e above
             "      # plus 'inspect' entries discussed in section 6b below

       If  a  valid  absolute  path to the rcfile cannot be established, customizations made to a
       running top will be impossible to preserve.

   6b. ADDING INSPECT Entries
       To exploit the `Y' interactive command, you must  add  entries  at  the  end  of  the  top
       personal  configuration  file.   Such  entries  simply  reflect  a  file  to  be  read  or
       command/pipeline to be executed whose  results  will  then  be  displayed  in  a  separate
       scrollable, searchable window.

       If you don't know the location or name of your top rcfile, use the `W' interactive command
       to rewrite it and note those details.

       Inspect entries can be added with a redirected echo or by editing the configuration  file.
       Redirecting  an echo risks overwriting the rcfile should it replace (>) rather than append
       (>>) to that file.  Conversely, when using an editor care must be  taken  not  to  corrupt
       existing lines, some of which will contain unprintable data or unusual characters.

       Those  Inspect  entries beginning with a `#' character are ignored, regardless of content.
       Otherwise they consist of the following 3 elements, each of which must be separated  by  a
       tab character (thus 2 `\t' total):

         .type:  literal `file' or `pipe'
         .name:  selection shown on the Inspect screen
         .fmts:  string representing a path or command

       The two types of Inspect entries are not interchangeable.  Those designated `file' will be
       accessed using fopen and must reference a single file in  the  `.fmts'  element.   Entries
       specifying  `pipe'  will  employ popen, their `.fmts' element could contain many pipelined
       commands and, none can be interactive.

       If the file or pipeline represented in your `.fmts' deals with the specific PID  input  or
       accepted  when  prompted,  then the format string must also contain the `%d' specifier, as
       these examples illustrate.

         .fmts=  /proc/%d/numa_maps
         .fmts=  lsof -P -p %d

       For `pipe' type entries only, you may also wish to redirect stderr to stdout  for  a  more
       comprehensive result.  Thus the format string becomes:

         .fmts=  pmap -x %d 2>&1

       Here  are  examples  of  both types of Inspect entries as they might appear in the rcfile.
       The first entry will be ignored due to the initial `#' character.  For clarity, the pseudo
       tab depictions (^I) are surrounded by an extra space but the actual tabs would not be.

         # pipe ^I Sockets ^I lsof -n -P -i 2>&1
         pipe ^I Open Files ^I lsof -P -p %d 2>&1
         file ^I NUMA Info ^I /proc/%d/numa_maps
         pipe ^I Log ^I tail -n100 /var/log/syslog | sort -Mr

       Except  for  the  commented  entry above, these next examples show what could be echoed to
       achieve similar results, assuming the rcfile name  was  `.toprc'.   However,  due  to  the
       embedded  tab  characters,  each  of these lines should be preceded by `/bin/echo -e', not
       just a simple an `echo', to enable backslash interpretation regardless of which shell  you
       use.

         "pipe\tOpen Files\tlsof -P -p %d 2>&1" >> ~/.toprc
         "file\tNUMA Info\t/proc/%d/numa_maps" >> ~/.toprc
         "pipe\tLog\ttail -n200 /var/log/syslog | sort -Mr" >> ~/.toprc

       If  any  inspect entry you create produces output with unprintable characters they will be
       displayed in either the ^C notation or hexadecimal <FF> form, depending  on  their  value.
       This  applies  to  tab  characters  as well, which will show as `^I'.  If you want a truer
       representation, any embedded tabs should be expanded.  The following  example  takes  what
       could  have  been a `file' entry but employs a `pipe' instead so as to expand the embedded
       tabs.

         # next would have contained `\t' ...
         # file ^I <your_name> ^I /proc/%d/status
         # but this will eliminate embedded `\t' ...
         pipe ^I <your_name> ^I cat /proc/%d/status | expand -

       Note: Some programs might rely on SIGINT to end.  Therefore,  if  a  `pipe'  such  as  the
       following  is  established,  one  must  use  Ctrl-C to terminate it in order to review the
       results.  This is the single occasion where a `^C' will not also terminate top.

         pipe ^I Trace ^I /usr/bin/strace -p %d 2>&1

       Lastly, while `pipe' type entries have been discussed in terms of pipelines and  commands,
       there is nothing to prevent you from including  shell scripts as well.  Perhaps even newly
       created scripts designed specifically for the `Y' interactive command.

       For example, as the number of your Inspect entries grows over  time,  the  `Options:'  row
       will  be  truncated  when  screen width is exceeded.  That does not affect operation other
       than to make some selections invisible.  However, if some choices are lost  to  truncation
       but you want to see more options, there is an easy solution hinted at below.

         Inspection Pause at pid ...
         Use:  left/right then <Enter> ...
         Options:  help  1  2  3  4  5  6  7  8  9  10  11 ...

       The  entries  in the top rcfile would have a number for the `.name' element and the `help'
       entry would identify  a  shell  script  you've  written  explaining  what  those  numbered
       selections actually mean.  In that way, many more choices can be made visible.

   6c. SYSTEM Configuration File
       This  configuration  file  represents  defaults  for  users  who  have not saved their own
       configuration file.  The format mirrors exactly the personal configuration  file  and  can
       also include `inspect' entries as explained above.

       Creating it is a simple process.

       1.  Configure top appropriately for your installation and preserve that configuration with
       the `W' interactive command.

       2. Add and test any desired `inspect' entries.

       3. Copy that configuration file to the /etc/ directory as `topdefaultrc'.

   6d. SYSTEM Restrictions 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

       This configuration file is not created by top.  Rather, it is created manually and  placed
       it in the /etc/ directory as `toprc'.

       It should have exactly two lines, as shown in this example:
           s        # line 1: secure mode switch
           5.0      # line 2: delay interval in seconds

7. 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.

   7a. 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 so as 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, on top's Color Mapping screen set the
          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 4c. 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.

   7b. 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  using  the  `i'  command  toggle.   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 (`m'); another with no
          states (`t'); 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 using the `i'
          command toggle.  You've just entered the "extreme bounce" zone.

   7c. 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  with  the  `n'  interactive  command until all the other task
          displays are "pushed out of the nest".

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

   7d. The Ol' Switcheroo
       This stupid trick works best without alternate-display mode, since justification is active
       on a per window basis.

       ·  Start top and make COMMAND the last (rightmost) column displayed.   If  necessary,  use
          the  `c'  command  toggle  to display command lines and ensure that forest view mode is
          active with the `V' command toggle.

          Then use the up/down arrow keys to position the display so that some truncated  command
          lines  are  shown (`+' in last position).  You may have to resize your xterm to produce
          truncation.

          Lastly, use the `j' command toggle to make the COMMAND column right justified.

          Now use the right arrow key to reach the COMMAND column.   Continuing  with  the  right
          arrow key, watch closely the direction of travel for the command lines being shown.

             some lines travel left, while others travel right

             eventually all lines will Switcheroo, and move right

8. BUGS

       Please send bug reports to ⟨procps@freelists.org⟩.

9. SEE Also

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