TOP(1)



TOP(1)                           User Commands                          TOP(1)

NAME
       top - display Linux processes

SYNOPSIS
       top -hv|-bcEHiOSs1 -d secs -n max -u|U user -p pid -o fld -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  pro-
       cesses  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 manip-
       ulation as well as a much more extensive interface for personal config-
       uration  --  encompassing every aspect of its operation.  And while top
       is  referred to throughout this document, you are free to name the pro-
       gram anything you wish.  That new name, possibly an alias, will then be
       reflected on top's display and used when reading and writing a configu-
       ration 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 tradi-
       tional interrupt key (^C) when you're done.

       When started for the first time, you'll be presented with these  tradi-
       tional elements on the main top screen: 1) Summary Area; 2) Fields/Col-
       umns Header; 3) Task Area.  Each of these will be explored in the  sec-
       tions  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, espe-
       cially those with static text.  It ultimately depends, however, on your
       particular  window  manager  and terminal emulator.  There may be occa-
       sions 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 re-
       suming 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  cur-
       rently 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. COM-
       MAND-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 mem-
       ory, 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 dis-
       played 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|-bcEHiOSs1 -d secs -n max -u|U user -p pid -o fld -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 addi-
            tional information.

       -d  :Delay-time interval as:  -d ss.t (secs.tenths)
            Specifies the delay between screen updates, and overrides the cor-
            responding  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 al-
            lowed.  In all cases, however, such changes are prohibited if  top
            is  running  in  Secure mode, except for root (unless the `s' com-
            mand-line option was used).  For additional information on  Secure
            mode see topic 6d. SYSTEM Restrictions File.

       -E  :Extend-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 com-
            mand-line option a summation of all threads  in  each  process  is
            shown.   Later  this  can be changed with the `H' interactive com-
            mand.

       -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 up-
            date 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, in-
            dependent 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  permit-
            ted.

            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 Cu-
            mulative 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 in-
            structs 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 out-
            put 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 at-
            tempt to format output using the COLUMNS= and  LINES=  environment
            variables, if set.  With an argument, output width can only be de-
            creased, not increased.  Whether using environment variables or an
            argument  with  -w,  when not in Batch mode actual terminal dimen-
            sions 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 sum-
            mary  area reversed.  Either all cpu information will be displayed
            in a single line or each cpu will be displayed separately, depend-
            ing on the state of the NUMA Node command toggle ('2').

            See  the  `1' and '2' interactive commands for additional informa-
            tion.

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  environ-
       ment, 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 dis-
       played.  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 combined us and ni percentage; b) is the sy percent-
       age; c) is the total; and d) is one of two visual graphs of those  rep-
       resentations.   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  avail-
       able  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 mi-
       nus 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 ad-
       ditional 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 po-
       sition 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,  how-
       ever,  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 up-
           date, 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  com-
           mand.

           Also  for  multi-processor  environments,  if Irix mode is Off, top
           will operate in Solaris mode where a task's cpu usage will  be  di-
           vided  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  col-
           lapsed  (`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, net-
           work bandwidth, etc.) among  installation-defined  groups  of  pro-
           cesses.  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 charac-
           ters).   Even  so,  such  variable  width fields could still suffer
           truncation.  See topic 5c. SCROLLING a Window for additional infor-
           mation 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  com-
           mand.

           When  you've  chosen  to display command lines, processes without a
           command line (like kernel threads) will be shown with only the pro-
           gram 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  regard-
           ing 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 charac-
           ters).  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 charac-
           ters).   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  deter-
           mining 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  informa-
           tion is not available.

           See  the `'2' and `3' interactive commands for additional NUMA pro-
           visions 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 envi-
           ronment  this will likely change frequently since the kernel inten-
           tionally 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 be-
           comes  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 pri-
           ority.

           Under linux, real time priority is somewhat misleading since tradi-
           tionally  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 repre-
           sented 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 im-
           pact 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 pro-
           cesses.  It will include shared anonymous pages  and  shared  file-
           backed  pages.  It also includes private pages mapped to files rep-
           resenting 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 es-
           tablished  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  in-
           herited from a task's parent.  They are displayed in a comma delim-
           ited 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 charac-
           ters).   Even  so,  such  variable  width fields could still suffer
           truncation.  See topic 5c. SCROLLING a Window for additional infor-
           mation on accessing any truncated data.

       34. SUPGRPS  --  Supplementary Group Names
           The names of any supplementary group(s) established at login or in-
           herited from a task's parent.  They are displayed in a comma delim-
           ited 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 charac-
           ters).  Even so, such variable  width  fields  could  still  suffer
           truncation.  See topic 5c. SCROLLING a Window for additional infor-
           mation 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 regard-
           ing this mode.

       39. TIME+  --  CPU Time, hundredths
           The same as TIME, but  reflecting  more  granularity  through  hun-
           dredths 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 conven-
           tion,  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 as-
           sociated 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 us-
           ing (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 aux-
           iliary 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 communica-
           tion (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  net-
           work devices, IP addresses, IP routing, port numbers, etc.

       54. nsPID  --  PID namespace
           The Inode of the namespace used to isolate process ID numbers mean-
           ing they need not remain unique.  Thus, each such  namespace  could
           have  its own `init/systemd' (PID #1) to manage various initializa-
           tion 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  or-
       der  along  with descriptions.  Entries marked with an asterisk are the
       currently displayed fields, screen width permitting.

           o  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.

           o  The  Right  arrow  key selects a field for repositioning and the
              Left arrow key or the <Enter> key commits  that  field's  place-
              ment.

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

           o  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.

           o  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-DIS-
       PLAY  Provisions and the `g' interactive command for insight into `cur-
       rent' 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 ver-
       tical 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 com-
       mands  appear  more  than once  --  their meaning or scope may vary de-
       pending 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
         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  se-
       cured,  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  se-
              cured, that screen will be abbreviated.

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

          =  :Exit-Task-Limits
              Removes restrictions on which tasks  are  shown.   This  command
              will reverse any `i' (idle tasks), `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 and
              Locate processing.

              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 alter-
              nate-display mode.  See topic  5.  ALTERNATE-DISPLAY  Provisions
              and  the `g' interactive command for insight into `current' win-
              dows 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 termi-
              nals, 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,  un-
              less  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,  be-
              tween display updates.

              Fractional seconds are honored, but a negative number is not al-
              lowed.  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  propor-
              tional 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  :Extend-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  :Extend-Memory-Scale in Task Windows
              With this command you can cycle through the available task  win-
              dow  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,  addi-
              tional  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 ac-
              complish 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 designat-
              ing  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  dis-
              plays 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  issu-
              ing 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, ordi-
              nary 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 be-
              fore 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 de-
              faults.

              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  re-
              sults  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 sup-
              porting 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  re-
              flected  in its header prologue.  There are, however, additional
              keys available once you have selected a particular file or  com-
              mand.  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 Se-
          cure 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  com-
       mand 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 infor-
              mation 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'  win-
              dow name when operating in alternate-display mode.

          t  :Task/Cpu-States toggle
              This  command affects from 2 to many summary area lines, depend-
              ing 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  be-
              comes  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  mas-
              sively-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.  Other-
              wise, 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 requi-
              site 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 either the `1' or `2' command tog-
              gle is pressed.  This interactive command is only available if a
              system has the requisite NUMA support.

       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 alter-
       nate-display mode if the `current' window's task display has been  tog-
       gled Off (see topic 5. ALTERNATE-DISPLAY Provisions).

       APPEARANCE of task window

          J  :Justify-Numeric-Columns toggle
              Alternates between right-justified (the default) and left-justi-
              fied 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-justi-
              fied 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  dis-
              played.   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 in-
              sight into this  task  state,  see  topic  3a.  DESCRIPTIONS  of
              Fields, the `S' field (Process Status).

              Use  of this provision provides important insight into your sys-
              tem's health.  The only costs will be a few additional  tty  es-
              cape 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 de-
              termines 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 ad-
              ditional 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 ap-
              pear less demanding.  For programs like `init' or a  shell  this
              is appropriate but for others, like compilers, perhaps not.  Ex-
              periment with two task windows sharing the same sort  field  but
              with  different `S' states and see which representation you pre-
              fer.

              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 pro-
              gram 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 Com-
              mands, SORTING for information on those keys.

          v  :Hide/Show-Children toggle
              When  in  forest  view mode, this key serves as a toggle to col-
              lapse 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 addi-
              tional 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 ap-
              pear to have used no CPU.

              If  this command is applied to the last task display when in al-
              ternate-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  visi-
              ble  task display, except for the very last.  It will not affect
              the last window's size, as all prior task displays will have al-
              ready 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'  interac-
          tive  command.   That will help ensure that the actual sort environ-
          ment 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  func-
                 tions.   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  dis-
          play.  Thus, the TTY and WCHAN fields will violate strict ASCII col-
          lating 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 ap-
       plied 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'  win-
       dow/field  group  in either full-screen mode or alternate-display mode.
       Whatever was targeted when `q' or <Enter> was pressed will be made cur-
       rent 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 en-
          tire screen.  That single window can still be changed to  display  1
          of  4  different  field groups (see the `g' interactive command, re-
          peated 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 sum-
          mary area line Off.  With the loss of the window name (the `l'  tog-
          gled line), you'll not easily know what window is the `current' win-
          dow.

   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 ap-
              plied 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 dis-
              plays are currently visible, this interactive command will leave
              the summary area as the only display element.

       *  = | +  :Equalize-(reinitialize)-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)  and  'L'  (locate) 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 ver-
              tical and horizontal scrolling.

              The `+' key does the same for all windows.  The four  task  dis-
              plays  will  reappear, evenly balanced.  They will also have re-
              tained any customizations you had previously applied, except for
              the  `i'  (idle  tasks),  `n'  (max tasks), `u/U' (user filter),
              `o/O' (other filter), `v'  (hide  children),  `L'  (locate)  and
              scrolling interactive commands.

       *  A  :Alternate-Display-Mode toggle
              This  command  will  switch  between full-screen mode and alter-
              nate-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 cir-
              cular 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  empha-
              sis/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 designat-
              ing 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 `cur-
              rent' window.  It does not require that the window name be visi-
              ble (the `l' toggle to be On).

       *  The  interactive  commands shown with an asterisk (`*') have use be-
          yond 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  hori-
       zontally 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  col-
           umn 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 dis-
           placement  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 con-
               trolled by scrolling keys.  The second n is  updated  automati-
               cally 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' interac-
               tive 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 start-
           ing 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 follow-
       ing 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) po-
       sition, 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  es-
       cape  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'  win-
       dow.   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'  win-
             dow.   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 com-
             mand, 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 ei-
          ther equality (`=') or relation (`<' or `>').

          The `=' equality operator requires only a partial match and that can
          reduce  your  `if-value'  input  requirements.  The `>' or `<' rela-
          tional operators always employ string comparisons, even with numeric
          fields.  They are designed to work with a field's default justifica-
          tion 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  de-
          fault  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 justifica-
          tion 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 sec-
          ond 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 mislead-
          ing  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  ap-
          plied to achieve almost any desired result.  Single quotes are some-
          times 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  fil-
          ter 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  in-
          put.   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-dis-
       play escape sequences.  Such highlighting will be restored when a  win-
       dow 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,graph modes
             "      # 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,  cus-
       tomizations 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.  Con-
       versely, when using an editor care must be taken not to corrupt  exist-
       ing lines, some of which will contain unprintable data or unusual char-
       acters.

       Those Inspect entries beginning with a `#' character are  ignored,  re-
       gardless  of  content.   Otherwise they consist of the following 3 ele-
       ments, 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 desig-
       nated `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 spe-
       cific 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  be-
       comes:

         .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 char-
       acters 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 occa-
       sion 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 pipe-
       lines  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' ele-
       ment 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  `topde-
       faultrc'.

   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 com-
       mands.
           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.

       o  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.

       o  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 highlight-
          ing 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.

       o  Delete the existing rcfile, or create a new symlink.  Start this new
          version  then  type  `T' (a secret key, see topic 4c. Task Area Com-
          mands, SORTING) followed by `W' and `q'.  Finally, restart the  pro-
          gram 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.

       o  With 3 or 4 task displays visible, pick any window  other  than  the
          last  and turn idle processes Off using the `i' command toggle.  De-
          pending 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.

       o  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 varia-
          tion on bouncing windows  --  hopping windows.

       o  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.

       o  Display all 4 windows and make sure that 1:Def is the `current' win-
          dow.  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/invisi-
          ble 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 jus-
       tification is active on a per window basis.

       o  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 tog-
          gle.

          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)

procps-ng                        October 2019                           TOP(1)

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