man > TOP(1)

TLDR: TOP (tldr-pages)

Display dynamic real-time information about running processes.

  • Start `top`
    top
  • Do not show any idle or zombie processes
    top {{-i|--idle-toggle}}
  • Show only processes owned by given user
    top {{-u|--filter-only-euser}} {{username}}
  • Sort processes by a field
    top {{-o|--sort-override}} {{field_name}}
  • Show the individual threads of a given process
    top {{-Hp|--threads-show --pid}} {{process_id}}
  • Show only the processes with the given PID(s), passed as a comma-separated list. (Normally you wouldn't know PIDs off hand. This example picks the PIDs from the process name)
    top {{-p|--pid}} $(pgrep {{-d|--delimiter}} ',' {{process_name}})
  • Display help about interactive commands
    <?>
TOP(1)                                      User Commands                                     TOP(1)

NAME
       top - display Linux processes


SYNOPSIS
       top [options]


DESCRIPTION
       The top program provides a dynamic real-time view of a running system.  It can display system
       summary  information as well as a list of processes or threads currently being managed by the
       Linux kernel.  The types of system summary information shown and the types, order and size of
       information displayed for processes are all user configurable and that configuration  can  be
       made persistent across restarts.

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


OVERVIEW
   Documentation
       The remaining Table of Contents

           OVERVIEW
              Operation
              Linux Memory Types
           1. COMMAND-LINE Options
           2. SUMMARY Display
              a. UPTIME and LOAD Averages
              b. TASK and CPU States
              c. MEMORY Usage
           3. FIELDS / Columns Display
              a. DESCRIPTIONS of Fields
              b. MANAGING Fields
           4. INTERACTIVE Commands
              a. GLOBAL Commands
              b. SUMMARY AREA Commands
              c. TASK AREA Commands
                 1. Appearance
                 2. Content
                 3. Size
                 4. Sorting
              d. COLOR Mapping
           5. ALTERNATE-DISPLAY Provisions
              a. WINDOWS Overview
              b. COMMANDS for Windows
              c. SCROLLING a Window
              d. SEARCHING in a Window
              e. FILTERING in a Window
           6. FILES
              a. PERSONAL Configuration File
              b. ADDING INSPECT Entries
              c. SYSTEM Configuration File
              d. SYSTEM Restrictions File
           7. ENVIRONMENT VARIABLE(S)
           8. STUPID TRICKS Sampler
              a. Kernel Magic
              b. Bouncing Windows
              c. The Big Bird Window
              d. The Ol' Switcheroo
           9. BUGS, 10. SEE Also


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

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

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

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

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

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

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

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


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

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

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

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

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

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

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

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


1. COMMAND-LINE Options
       Mandatory arguments to long options are mandatory for short options too.

       Although  not  required,  the  equals sign can be used with either option form and whitespace
       before and/or after the `=' is permitted.


       -b, --batch
          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, --cmdline-toggle
          Starts top with the last remembered `c' state  reversed.   Thus,  if  top  was  displaying
          command  lines,  now  that  field  will  show  program names, and vice versa.  See the `c'
          interactive command for additional information.


       -d, --delay = SECS [.TENTHS]
          Specifies the delay between screen updates, and overrides the corresponding value in one's
          personal configuration file or the startup default.  Later this can be  changed  with  the
          `d' or `s' interactive commands.

          Fractional  seconds  are  honored,  but  a  negative number is not allowed.  In all cases,
          however, such changes are prohibited if top is running in Secure  mode,  except  for  root
          (unless  the `s' command-line option was used).  For additional information on Secure mode
          see topic 6d. SYSTEM Restrictions File.


       -E, --scale-summary-mem = 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.


       -e, --scale-task-mem = k | m | g | t | p
          Instructs top to force task area memory to be scaled as:
             k - kibibytes
             m - mebibytes
             g - gibibytes
             t - tebibytes
             p - pebibytes

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


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


       -h, --help
          Display usage help text, then quit.


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


       -n, --iterations = NUMBER
          Specifies the maximum number of iterations, or frames, top should produce before ending.


       -O, --list-fields
          This  option  acts  as a form of help for the -o option shown below.  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.


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

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


       -p, --pid = PIDLIST (as: 1,2,3, ... or -p1 -p2 -p3 ...)
          Monitor  only  processes  with specified process IDs.  However, when combined with Threads
          mode (`H'), all processes in the thread group (see TGID) of each monitored PID  will  also
          be shown.

          This option can be given up to 20 times, or you can provide a comma delimited list with up
          to 20 pids.  Co-mingling both approaches is permitted.

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

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

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


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


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


       -U, --filter-any-user = USER (as: number or name)
          Display  only  processes  with  a  user  id or user name matching that given.  This option
          matches on any user (real, effective, saved, or filesystem).

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

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


       -u, --filter-only-euser = USER (as: number or name)
          Display only processes with a user id or user  name  matching  that  given.   This  option
          matches on the effective user id only.

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

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


       -V, --version
          Display version information, then quit.


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

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

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


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

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


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


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


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

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

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

       As  a  default, percentages for these individual categories are displayed.  Depending on your
       kernel version, the st field may not be shown.
           us : time running un-niced user processes
           sy : time running kernel processes
           ni : time running niced user processes
           id : time spent in the kernel idle handler
           wa : 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

       The `sy' value above also reflects the  time  running  a  virtual  cpu  for  guest  operating
       systems, including those that have been niced.

       Beyond  the first tasks/threads line, there are alternate CPU display modes available via the
       4-way `t' command toggle.  They show an abbreviated summary consisting of these elements:
                      a    b     c    d
           %Cpu(s):  75.0/25.0  100[ ... ]


       Where: a) is the `user' (us + ni) percentage; b) is the `system' (sy +  hi  +  si  +  guests)
       percentage;  c)  is  the  total  percentage;  and  d)  is  one  of two visual graphs of those
       representations.  Such graphs also reflect separate `user' and `system' portions.

       If the `4' command toggle is used to yield more than two  cpus  per  line,  results  will  be
       further  abridged  eliminating  the  a)  and b) elements.  However, that information is still
       reflected in the graph itself assuming color is active or, if not, bars vs. blocks are  being
       shown.

       See  topic  4b.  SUMMARY  AREA Commands for additional information on the `t' and `4' command
       toggles.


   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.
       The /proc/meminfo source fields are shown in parenthesis.

       Line 1 reflects physical memory, classified as:
           total          ( MemTotal )
           free           ( MemFree )
           used           ( MemTotal - MemAvailable )
           buff/cache     ( Buffers + Cached + SReclaimable )

       Line 2 reflects mostly virtual memory, classified as:
           total          ( SwapTotal )
           free           ( SwapFree )
           used           ( SwapTotal - SwapFree )
           avail          ( MemAvailable, which is physical memory )

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

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

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

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

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


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

       Any field is selectable as the sort field, and you control whether they are  sorted  high-to-
       low  or  low-to-high.   For additional information on sort provisions see topic 4c. TASK AREA
       Commands, SORTING.

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


       %CPU  --  CPU Usage
           The  task's  share  of  the elapsed CPU time since the last screen update, expressed as a
           percentage of total CPU time.

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

           Also for multi-processor environments, if Irix mode is Off, top will operate  in  Solaris
           mode  where  a  task's cpu usage will be divided by the total number of CPUs.  You toggle
           Irix/Solaris modes with the `I' interactive command.

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


       %CUC  --  CPU Utilization
           This field is identical to %CUU below, except the percentage also reflects  reaped  child
           processes.


       %CUU  --  CPU Utilization
           A task's total CPU usage divided by its elapsed running time, expressed as a percentage.

           If  a  process  currently  displays high CPU usage, this field can help determine if such
           behavior is normal.  Conversely, if a process has  low  CPU  usage  currently,  %CUU  may
           reflect historically higher demands over its lifetime.


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

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


       AGID  --  Autogroup Identifier
           The autogroup identifier associated with a process.  This feature operates in conjunction
           with the CFS scheduler to improve interactive desktop performance.

           When  /proc/sys/kernel/sched_autogroup_enabled  is  set,  a new autogroup is created with
           each new session (see SID).  All subsequently forked processes in  that  session  inherit
           membership  in  this autogroup.  The kernel then attempts to equalize distribution of CPU
           cycles across such groups.  Thus, an autogroup with many  CPU  intensive  processes  (e.g
           make -j) will not dominate an autogroup with only one or two processes.

           When -1 is displayed it means this information is not available.


       AGNI  --  Autogroup Nice Value
           The  autogroup  nice  value  which  affects scheduling of all processes in that group.  A
           negative nice value means higher priority, whereas a  positive  nice  value  means  lower
           priority.


       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.


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

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

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

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


       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.


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

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

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

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


       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.


       ELAPSED  --  Elapsed Running Time
           The length of time since a process was started.  Thus, the  most  recently  started  task
           will display the smallest time interval.

           The  value  will  be  expressed  as  `HH,MM' (hours,minutes) but is subject to additional
           scaling if the interval becomes too great to fit column width.  At that point it will  be
           scaled to `DD+HH' (days+hours) and possibly beyond.


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

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


       EXE  --  Executable Path
           Where available, this is the full path to the executable, including the program name.

           Note:  The  EXE  field, unlike most columns, is not fixed-width.  When displayed, it plus
           any other variable width columns will be allocated all remaining screen width (up to  the
           maximum 512 characters).


       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>.


       GID  --  Group Id
           The effective group ID.


       GROUP  --  Group Name
           The effective group name.


       LOGID  --  Login User Id
           The user ID used at login.  When -1  is  displayed  it  means  this  information  is  not
           available.


       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.


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

           Note: This value only affects scheduling priority relative to other processes in the same
           autogroup.  See the `AGID' and `AGNI' fields for additional information on autogroups.


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

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


       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.


       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'.


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


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


       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).


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


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

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


       PSS  --  Proportional Resident Memory, smaps (KiB)
           The  proportion of this task's share of `RSS' where each page is divided by the number of
           processes sharing it.  It is also the sum of the `PSan', `PSfd' and `PSsh' fields.

           For example, if a process has 1000 resident pages alone and 1000  resident  pages  shared
           with another process, its `PSS' would be 1500 (times page size).

           Accessing smaps values is 10x more costly than other memory statistics and data for other
           users requires root privileges.


       PSan  --  Proportional Anonymous Memory, smaps (KiB)
       PSfd  --  Proportional File Memory, smaps (KiB)
       PSsh  --  Proportional Shmem Memory, smaps (KiB)
           As  was true for `PSS' above (total proportional resident memory), these fields represent
           the proportion of this task's share of each type of  memory  divided  by  the  number  of
           processes sharing it.

           Accessing smaps values is 10x more costly than other memory statistics and data for other
           users requires root privileges.


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

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

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

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


       RSS  --  Resident Memory, smaps (KiB)
           Another,  more  precise view of process non-swapped physical memory.  It is obtained from
           the `smaps_rollup' file and is generally slightly larger than that shown for `RES'.

           Accessing smaps values is 10x more costly than other memory statistics and data for other
           users requires root privileges.


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


       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.


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


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


       RUID  --  Real User Id
           The real user ID.


       RUSER  --  Real User Name
           The real user name.


       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.


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

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


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


       STARTED  --  Start Time Interval
           The  length  of  time  since system boot when a process started.  Thus, the most recently
           started task will display the largest time interval.

           The value will be expressed as `MM:SS' (minutes:seconds).  But if  the  interval  is  too
           great  to  fit  column  width  it  will be scaled as `HH,MM' (hours,minutes) and possibly
           beyond.


       SUID  --  Saved User Id
           The saved user ID.


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

           Note:  The  SUPGIDS  field,  unlike most columns, is not fixed-width.  When displayed, it
           plus any other variable width columns will be allocated all remaining screen width (up to
           the maximum 512 characters).


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

           Note:  The  SUPGRPS  field,  unlike most columns, is not fixed-width.  When displayed, it
           plus any other variable width columns will be allocated all remaining screen width (up to
           the maximum 512 characters).


       SUSER  --  Saved User Name
           The saved user name.


       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.


       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.


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


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


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


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


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


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

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


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


       USS  --  Unique Set Size
           The non-swapped portion of physical memory (`RSS') not shared with any other process.  It
           is derived from the `smaps_rollup' file.

           Accessing smaps values is 10x more costly than other memory statistics and data for other
           users requires root privileges.


       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.


       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.


       ioR  --  I/O Bytes Read
           The number of bytes a process caused to be fetched from the storage layer.

           Root privileges are required to display `io' data for other users.


       ioRop  --  I/O Read Operations
           The  number of read I/O operations (syscalls) for a process.  Such calls might not result
           in actual physical disk I/O.


       ioW  --  I/O Bytes Written
           The number of bytes a process caused to be sent to the storage layer.


       ioWop  --  I/O Write Operations
           The number of write I/O operations (syscalls) for a process.  Such calls might not result
           in actual physical disk I/O.


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

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


       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.


       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.


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


       nsCGROUP  --  CGROUP namespace
           The  Inode  of  the  namespace  used  to  hide the identity of the control group of which
           process is a member.


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


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


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


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


       nsTIME  --  TIME namespace
           The  Inode of the namespace which allows processes to see different system times in a way
           similar to the UTS namespace.


       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.


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


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


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


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


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


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


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


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


       The Fields Management screen can also be used to change the `current' window/field  group  in
       either  full-screen  mode or alternate-display mode.  Whatever was targeted when `q' or <Esc>
       was pressed will  be  made  current  as  you  return  to  the  top  display.   See  topic  5.
       ALTERNATE-DISPLAY  Provisions  and  the  `g'  interactive  command for insight into `current'
       windows and field groups.


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


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

         4a. Global-Commands
               <Ent/Sp> ?, =, 0,
               A, B, d, E, e, g, H, h, I, k, q, r, s, W, X, Y, Z,
               ^G, ^K, ^N, ^P, ^U, ^L, ^R
         4b. Summary-Area-Commands
               C, l, t, m, 1, 2, 3, 4, 5, !
         4c. Task-Area-Commands
               Appearance:  b, J, j, x, y, z
               Content:     c, F, f, O, o, S, U, u, V, v, ^E
               Size:        #, i, n
               Sorting:     <, >, 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, &
         5e. Filtering-in-a-Window
               O, o, ^O, =, +


   4a. GLOBAL Commands
       The   global  interactive  commands  are  always  available  in  both  full-screen  mode  and
       alternate-display mode.  However, some of these interactive commands are not  available  when
       running in Secure mode.

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


         <Enter> or <Space>  :Refresh-Display
              These commands awaken top and following receipt of any input the entire  display  will
              be  repainted.   They  also  force  an update of any hotplugged cpu or physical memory
              changes.

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


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

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


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

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


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


          A  :Alternate-Display-Mode toggle
              This  command  will  switch  between full-screen mode and alternate-display mode.  See
              topic 5. ALTERNATE-DISPLAY Provisions and the `g' interactive command for insight into
              `current' windows and field groups.


          B  :Bold-Disable/Enable toggle
              This command will influence use of the bold terminfo capability and  alters  both  the
              summary  area  and task area for the `current' window.  While it is intended primarily
              for use with dumb terminals, it can be applied anytime.

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


       *  d | s  :Change-Delay-Time-interval
              You will be prompted to enter the delay time, in seconds, between display updates.

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

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


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

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


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

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


          g  :Choose-Another-Window/Field-Group
              You will be prompted to enter a number between 1 and 4  designating  the  field  group
              which  should be made the `current' window.  You will soon grow comfortable with these
              4 windows, especially after experimenting with alternate-display mode.


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


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


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

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

              The default signal, as reflected in the prompt, is SIGTERM.  However, you can send any
              signal, via number or name.

              If you wish to abort the kill process, do one  of  the  following  depending  on  your
              progress:
                  1) at the pid prompt, type an invalid number
                  2) at the signal prompt, type 0 (or any invalid signal)
                  3) at any prompt, type <Esc>


          q  :Quit


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

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

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

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


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


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

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

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

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

              If you enter a negative number, top will automatically increase  the  column  size  as
              needed until there is no more truncated data.

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


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

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

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

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


          Z  :Change-Color-Mapping
              This key will take you to a separate screen where you can change the  colors  for  the
              `current'  window, or for all windows.  For details regarding this interactive command
              see topic 4d. COLOR Mapping.


         ^G  :Display-Control-Groups        (Ctrl key + `g')
         ^K  :Display-Cmdline               (Ctrl key + `k')
         ^N  :Display-Environment           (Ctrl key + `n')
         ^P  :Display-Namesspaces           (Ctrl key + `p')
         ^U  :Display-Supplementary-Groups  (Ctrl key + `u')
              Applied to the first process displayed, these commands  will  show  that  task's  full
              (potentially  wrapped)  information.  Such data will be displayed in a separate window
              at the bottom of the screen while normal top monitoring continues.

              Keying the same `Ctrl' command a second time removes that separate window as does  the
              `='  command.   Keying  a  different  `Ctrl' combination, while one is already active,
              immediately transitions to the new information.

              Notable among these provisions is the Ctrl+N (environment) command.  Its output can be
              extensive and not easily read when line wrapped.   A  more  readable  version  can  be
              achieved with an `Inspect' entry in the rcfile like the following.

                  pipe ^I Environment ^I cat /proc/%d/environ | tr '\0' '\n'

              See  the  `Y'  interactive  command  above  and  topic  6b. ADDING INSPECT Entries for
              additional information.

              As an alternative to `Inspect', and available to all of these `Ctrl' commands, the tab
              key can be used to highlight individual elements in the bottom window.


         ^L  :Logged-Messages  (Ctrl key + `l')
              The 10 most recent messages are displayed in a separate window at the  bottom  of  the
              screen  while normal top monitoring continues.  Keying `^L' a second time removes that
              window as does the `=' command.  Use the tab key to highlight individual messages.


       * ^R  :Renice-an-Autogroup  (Ctrl key + `r')
              You will be prompted for a PID and then the value for its autogroup AGNI.

              Entering no PID will be interpreted as the default shown in the prompt (the first task
              displayed).

              A positive AGNI value will  cause  processes  in  that  autogroup  to  lose  priority.
              Conversely,  a  negative  value causes them to be viewed more favorably by the kernel.
              Ordinary users are not allowed to set negative AGNI values.

              If you wish to abort the renice process type <Esc>.


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


   4b. SUMMARY AREA Commands
       The  summary  area  interactive  commands  are  always available in both full-screen mode and
       alternate-display mode.  They affect the beginning lines of your display and  will  determine
       the position of messages and prompts.

       These   commands  always  impact  just  the  `current'  window/field  group.   See  topic  5.
       ALTERNATE-DISPLAY Provisions and the `g'  interactive  command  for  insight  into  `current'
       windows and field groups.


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


          l  :Load-Average/Uptime toggle
              This is also the line containing the program name (possibly an alias)  when  operating
              in  full-screen  mode or the `current' window name when operating in alternate-display
              mode.


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

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

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

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


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

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


          1  :Single/Separate-Cpu-States toggle
              This command affects how the `t' command's Cpu States portion is shown.  Although this
              toggle exists primarily to serve massively-parallel SMP machines, it is not restricted
              to solely SMP environments.

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


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


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


          4  :Display-Multiple-Elements-Adjacent toggle
              This command toggle turns the `1' toggle Off and shows multiple CPU and Memory results
              on each line.  Each successive `4' key adds  another  CPU  until  again  reverting  to
              separate lines for CPU and Memory results.

              A  maximum  of  8  CPUs  per  line  can  be  displayed  in this manner.  However, data
              truncation may occur before reaching  the  maximum.   That  is  definitely  true  when
              displaying  detailed  statistics  via the `t' command toggle since such data cannot be
              scaled like the graphic representations.

              If one wished to quickly exit adjacent mode without cycling all the way to  8,  simply
              use the `1' command toggle.


          5  :Display-P-Cores-and-E-Cores toggle
              This command toggle is only active when the `t' toggle is On and the `1', `2', `3' and
              `!'  toggles  are Off, thus showing individual CPU results.  It assumes a platform has
              multiple cores of two  distinct  types,  either  multi-threaded  (P-Core)  or  single-
              threaded (E-Core).

              While  normally  each cpu is displayed as `%Cpu0, %Cpu1, ...', this toggle can be used
              to identify and/or filter those cpus by their core type, either  P-Core  (performance)
              or E-Core (efficient).

              The 1st time `5' is struck, each CPU is displayed as `%CpP' or `%CpE' representing the
              two  core types.  The 2nd time, only P-Cores (%CpP) will be shown.  The 3rd time, only
              E-Cores (%CpE) are displayed.  When this command toggle is struck for  the  4th  time,
              the CPU display returns to the normal `%Cpu' convention.

              If  separate performance and efficient categories are not present, this command toggle
              will have no effect.


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

              For example, with the first press of `!' two cpus will be combined  and  displayed  as
              `0-1, 2-3, ...' instead of the normal `%Cpu0, %Cpu1, %Cpu2, %Cpu3, ...'. With a second
              `!'  command  toggle  four  cpus  are combined and shown as `0-3, 4-7, ...'.  Then the
              third `!' press, combining eight cpus, shows as `0-7, 8-15, ...', etc.

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


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


   4c. TASK AREA Commands
       The task area interactive commands are always available in full-screen mode.

       The  task  area  interactive  commands  are  never available in alternate-display mode if the
       `current' window's task  display  has  been  toggled  Off  (see  topic  5.  ALTERNATE-DISPLAY
       Provisions).


       APPEARANCE of task window


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


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


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


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


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


          y  :Row-Highlight toggle
              Changes highlighting for "running" tasks.   For  additional  insight  into  this  task
              state, see topic 3a. DESCRIPTIONS of Fields, the `S' field (Process Status).

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


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


       CONTENT of task window


          c  :Command-Line/Program-Name toggle
              This command will be honored whether or not the COMMAND column is  currently  visible.
              Later, should that field come into view, the change you applied will be seen.


          F  :Maintain-Parent-Focus toggle
              When  in  forest  view  mode,  this key serves as a toggle to retain focus on a target
              task, presumably one with forked children.  If forest view mode is Off this key has no
              effect.

              The toggle is applied to the first (topmost) process in the  `current'  window.   Once
              established,  that  task is always displayed as the first (topmost) process along with
              its forked children.  All other processes will be suppressed.

              Note: keys like `i' (idle tasks), `n' (max tasks), `v' (hide children) and  User/Other
              filtering remain accessible and can impact what is displayed.


          f  :Fields-Management
              This  key  displays a separate screen where you can change which fields are displayed,
              their order and also designate the sort field.  For  additional  information  on  this
              interactive command see topic 3b. MANAGING Fields.


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

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


          S  :Cumulative-Time-Mode toggle
              When  Cumulative  mode is On, each process is listed with the cpu time that it and its
              dead children have used.

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

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


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

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

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


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

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


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

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

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


         ^E  :Scale-CPU-Time-fields (Ctrl key + `e')
              The `time' fields are normally displayed with  the  greatest  precision  their  widths
              permit.   This  toggle reduces that precision until it wraps.  It also illustrates the
              scaling those fields might experience automatically, which usually depends on how long
              the system runs.

              For example, if `MMM:SS.hh' is shown, each ^E keystroke would change it  to:  `MM:SS',
              `Hours,MM', `Days+Hours' and finally `Weeks+Days'.

              Not all time fields are subject to the full range of such scaling.


       SIZE of task window


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

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


          n | #  :Set-Maximum-Tasks
              You  will  be  prompted  to  enter the number of tasks to display.  The lessor of your
              number and available screen rows will be used.

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

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


       SORTING of task window

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

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

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


             <  :Move-Sort-Field-Left
                 Moves  the sort column to the left unless the current sort field is the first field
                 being displayed.


             >  :Move-Sort-Field-Right
                 Moves the sort column to the right unless the current sort field is the last  field
                 being displayed.


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


             f  :Fields-Management
                 This key displays a separate screen where you can change which field is used as the
                 sort column, among other functions.  This can be a convenient way to simply  verify
                 the current sort field, when running top with column highlighting turned Off.


             R  :Reverse/Normal-Sort-Field toggle
                 Using  this  interactive  command you can alternate between high-to-low and low-to-
                 high sorts.


   4d. COLOR Mapping
       When you issue the `Z' interactive command, you will be presented  with  a  separate  screen.
       That  screen  can  be  used  to change the colors in just the `current' window or in all four
       windows before returning to the top display.


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

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

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


5. ALTERNATE-DISPLAY Provisions
   5a. WINDOWS Overview
       Field Groups/Windows:
          In  full-screen  mode  there  is  a  single window represented by the entire screen.  That
          single window can still be changed to display 1 of 4 different field groups (see  the  `g'
          interactive  command, repeated below).  Each of the 4 field groups has a unique separately
          configurable summary area and its own configurable task area.

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

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


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

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


   5b. COMMANDS for Windows
          - | _  :Show/Hide-Window(s) toggles
              The  `-' key turns the `current' window's task display On and Off.  When On, that task
              area will show a minimum of  the  columns  header  you've  established  with  the  `f'
              interactive  command.  It will also reflect any other task area options/toggles you've
              applied yielding zero or more tasks.

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


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

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


       *  A  :Alternate-Display-Mode toggle
              This command will switch between full-screen mode and alternate-display mode.

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


       *  a | w  :Next-Window-Forward/Backward
              This  will  change  the  `current'  window,  which in turn changes the window to which
              commands are directed.  These keys act in a circular fashion  so  you  can  reach  any
              desired window using either key.

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


          G  :Change-Window/Field-Group-Name
              You  will  be  prompted for a new name to be applied to the `current' window.  It does
              not require that the window name be visible (the `l' toggle to be On).


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


       *  g  :Choose-Another-Window/Field-Group
              You  will  be  prompted  to enter a number between 1 and 4 designating the field group
              which should be made the `current' window.

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


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


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


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


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

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

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


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


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

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


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

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

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


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


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


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

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


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


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

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

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


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


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

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

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

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

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

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


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

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


   5e. FILTERING in a Window
       You can use this `Other Filter' feature to  establish  selection  criteria  which  will  then
       determine which tasks are shown in the `current' window.  Such filters can be made persistent
       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 (upper case)
             You will be prompted to establish a case sensitive filter.


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


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


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


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


       Input Requirements

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

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

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

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

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

       Potential Problems

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

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

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

       Potential Solutions

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

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

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

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


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

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

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

       While not intended to be edited manually, here is the general layout:
           global   # line  1: the program name/alias notation
             "      # line  2: id,altscr,irixps,delay,curwin
           per ea   # line  a: winname,fieldscur
           window   # line  b: winflags,sortindx,maxtasks,etc
             "      # line  c: summclr,msgsclr,headclr,taskclr
           global   # line 15: additional miscellaneous settings
             "      # any remaining lines are devoted to optional
             "      # active `other filters' discussed in section 5e above
             "      # plus `inspect' entries discussed in section 6b below

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

       Creating it is a simple process.

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

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

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


   6d. SYSTEM Restrictions File
       The  presence  of  this  file  will influence which version of the help screen is shown to an
       ordinary user.

       More importantly, it will limit what ordinary users are allowed to do when  top  is  running.
       They will not be able to issue the following commands.
           k        Kill a task
           r        Renice a task
           d or s   Change delay/sleep interval

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

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


7. ENVIRONMENT VARIABLE(S)
       The value set for the following is unimportant, just its presence.


       LIBPROC_HIDE_KERNEL
              This will prevent display of any kernel threads and exclude such  processes  from  the
              summary area Tasks/Threads counts.


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


   7a. Kernel Magic
       For these stupid tricks, top needs full-screen mode.


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

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

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


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

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


       •  Delete the existing rcfile, or create a new symlink.  Start this new version then type `T'
          (a  secret  key,  see  topic  4c.  Task  Area  Commands, SORTING) followed by `W' and `q'.
          Finally, restart the program with -d0 (zero delay).

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


   7b. Bouncing Windows
       For these stupid tricks, top needs alternate-display mode.


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


       •  Set each window's summary lines differently: one with no memory  (`m');  another  with  no
          states (`t'); maybe one with nothing at all, just the message line.  Then hold down `a' or
          `w' and watch a variation on bouncing windows  --  hopping windows.


       •  Display  all  4  windows  and  for  each, in turn, set idle processes to Off using the `i'
          command toggle.  You've just entered the "extreme bounce" zone.


   7c. The Big Bird Window
       This stupid trick also requires alternate-display mode.


       •  Display all 4 windows and make sure that  1:Def  is  the  `current'  window.   Then,  keep
          increasing  window size with the `n' interactive command until all the other task displays
          are "pushed out of the nest".

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


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


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

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

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

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

             some lines travel left, while others travel right

             eventually all lines will Switcheroo, and move right


9. BUGS
       Please send bug reports to ]8;;procps AT freelists.org\procps AT freelists.org]8;;\.



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

procps-ng                                    August 2023                                      TOP(1)
TOP(1)
NAME SYNOPSIS DESCRIPTION OVERVIEW
Documentation Operation Linux Memory Types 2a. UPTIME and LOAD Averages 2b. TASK and CPU States 2c. MEMORY Usage 3a. DESCRIPTIONS of Fields 3b. MANAGING Fields 4a. GLOBAL Commands 4b. SUMMARY AREA Commands 4c. TASK AREA Commands 4d. COLOR Mapping 5a. WINDOWS Overview 5b. COMMANDS for Windows 5c. SCROLLING a Window 5d. SEARCHING in a Window 5e. FILTERING in a Window Filter Basics Keyboard Summary Input Requirements Potential Problems Potential Solutions 6a. PERSONAL Configuration File 6b. ADDING INSPECT Entries 6c. SYSTEM Configuration File 6d. SYSTEM Restrictions File 7a. Kernel Magic 7b. Bouncing Windows 7c. The Big Bird Window 7d. The Ol' Switcheroo

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