neulab/tldr huggingface dataset:
The Up and Down arrow keys have special significance when prompted for line input terminated with the <Enter> key.  Those keys, or their aliases, can be used to retrieve previous input lines which can then be edited and re-input.  And there are four additional keys available with line oriented input. key      special-significance Up       recall older strings for re-editing Down     recall newer strings or erase entire line Insert   toggle between insert and overtype modes Delete   character removed at cursor, moving others left Home     jump to beginning of input line End      jump to end of input line
Linux Memory Types For our purposes there are three types of memory, and one is optional. First is physical memory, a limited resource where code and data must reside when executed or referenced.  Next is the optional swap file, where modified (dirty) memory can be saved and later retrieved if too many demands are made on physical memory.  Lastly we have virtual memory, a nearly unlimited resource serving the following goals:
1. abstraction, free from physical memory addresses/limits 2. isolation, every process in a separate address space 3. sharing, a single mapping can serve multiple needs 4. flexibility, assign a virtual address to a file
Regardless of which of these forms memory may take, all are managed as pages (typically 4096 bytes) but expressed by default in top as KiB (kibibyte).  The memory discussed under topic `2c. MEMORY Usage' deals with physical memory and the swap file for the system as a whole.  The memory reviewed in topic `3. FIELDS / Columns Display' embraces all three memory types, but for individual processes.
For each such process, every memory page is restricted to a single quadrant from the table below.  Both physical memory and virtual memory can include any of the four, while the swap file only includes #1 through #3.  The memory in quadrant #4, when modified, acts as its own dedicated swap file.
Private | Shared 1           |          2 Anonymous  . stack               | . malloc()            | . brk()/sbrk()        | . POSIX shm* . mmap(PRIVATE, ANON) | . mmap(SHARED, ANON) -----------------------+---------------------- . mmap(PRIVATE, fd)   | . mmap(SHARED, fd) File-backed  . pgms/shared libs    | 3           |          4
The following may help in interpreting process level memory values displayed as scalable columns and discussed under topic `3a. DESCRIPTIONS of Fields'.
%MEM - simply RES divided by total physical memory CODE - the `pgms' portion of quadrant 3 DATA - the entire quadrant 1 portion of VIRT plus all explicit mmap file-backed pages of quadrant 3 RES  - anything occupying physical memory which, beginning with Linux-4.5, is the sum of the following three fields: RSan - quadrant 1 pages, which include any former quadrant 3 pages if modified RSfd - quadrant 3 and quadrant 4 pages RSsh - quadrant 2 pages RSlk - subset of RES which cannot be swapped out (any quadrant) SHR  - subset of RES (excludes 1, includes all 2 & 4, some 3) SWAP - potentially any quadrant except 4 USED - simply the sum of RES and SWAP VIRT - everything in-use and/or reserved (all quadrants)
Note: Even though program images and shared libraries are considered private to a process, they will be accounted for as shared (SHR) by the kernel.
1. COMMAND-LINE Options The command-line syntax for top consists of:
-hv|-bcEeHiOSs1 -d secs -n max -u|U user -p pids -o field -w [cols]
The typically mandatory switch (`-') and even whitespace are completely optional.
-h | -v  :Help/Version Show library version and the usage prompt, then quit.
-b  :Batch-mode operation Starts top in Batch mode, which could be useful for sending output from top to other programs or to a file.  In this mode, top will not accept input and runs until the iterations limit you've set with the `-n' command-line option or until killed.
-c  :Command-line/Program-name toggle Starts top with the last remembered `c' state reversed.  Thus, if top was displaying command lines, now that field will show program names, and vice versa.  See the `c' interactive command for additional information.
-d  :Delay-time interval as:  -d ss.t (secs.tenths) Specifies the delay between screen updates, and overrides the corresponding value in one's personal configuration file or the startup default.  Later this can be changed with the `d' or `s' interactive commands.
Fractional seconds are honored, but a negative number is not allowed.  In all cases, however, such changes are prohibited if top is running in Secure mode, except for root (unless the `s' command-line option was used).  For additional information on Secure mode see topic 6d. SYSTEM Restrictions File.
-e  :Enforce-Task-Memory-Scaling as:  -e  k | m | g | t | p Instructs top to force task area memory to be scaled as: k - kibibytes m - mebibytes g - gibibytes t - tebibytes p - pebibytes
Later this can be changed with the `e' command toggle.
-E  :Enforce-Summary-Memory-Scaling as:  -E  k | m | g | t | p | e Instructs top to force summary area memory to be scaled as: k - kibibytes m - mebibytes g - gibibytes t - tebibytes p - pebibytes e - exbibytes
Later this can be changed with the `E' command toggle.
-H  :Threads-mode operation Instructs top to display individual threads.  Without this command-line option a summation of all threads in each process is shown.  Later this can be changed with the `H' interactive command.
-i  :Idle-process toggle Starts top with the last remembered `i' state reversed.  When this toggle is Off, tasks that have not used any CPU since the last update will not be displayed.  For additional information regarding this toggle see topic 4c. TASK AREA Commands, SIZE.
-n  :Number-of-iterations limit as:  -n number Specifies the maximum number of iterations, or frames, top should produce before ending.
-o  :Override-sort-field as:  -o fieldname Specifies the name of the field on which tasks will be sorted, independent of what is reflected in the configuration file.  You can prepend a `+' or `-' to the field name to also override the sort direction.  A leading `+' will force sorting high to low, whereas a `-' will ensure a low to high ordering.
This option exists primarily to support automated/scripted batch mode operation.
-O  :Output-field-names This option acts as a form of help for the above -o option.  It will cause top to print each of the available field names on a separate line, then quit.  Such names are subject to NLS (National Language Support) translation.
-p  :Monitor-PIDs mode as:  -pN1 -pN2 ...  or  -pN1,N2,N3 ... Monitor only processes with specified process IDs.  This option can be given up to 20 times, or you can provide a comma delimited list with up to 20 pids.  Co-mingling both approaches is permitted.
A pid value of zero will be treated as the process id of the top program itself once it is running.
This is a command-line option only and should you wish to return to normal operation, it is not necessary to quit and restart top  -- just issue any of these interactive commands: `=', `u' or `U'.
The `p', `u' and `U' command-line options are mutually exclusive.
-s  :Secure-mode operation Starts top with secure mode forced, even for root.  This mode is far better controlled through a system configuration file (see topic 6. FILES).
-S  :Cumulative-time toggle Starts top with the last remembered `S' state reversed.  When Cumulative time mode is On, each process is listed with the cpu time that it and its dead children have used.  See the `S' interactive command for additional information regarding this mode.
-u | -U  :User-filter-mode as:  -u | -U number or name Display only processes with a user id or user name matching that given.  The `-u' option matches on  effective user whereas the `-U' option matches on any user (real, effective, saved, or filesystem).
Prepending an exclamation point (`!') to the user id or name instructs top to display only processes with users not matching the one provided.
-w  :Output-width-override as:  -w [ number ] In Batch mode, when used without an argument top will format output using the COLUMNS= and LINES= environment variables, if set. Otherwise, width will be fixed at the maximum 512 columns.  With an argument, output width can be decreased or increased (up to 512) but the number of rows is considered unlimited.
In normal display mode, when used without an argument top will attempt to format output using the COLUMNS= and LINES= environment variables, if set.  With an argument, output width can only be decreased, not increased.  Whether using environment variables or an argument with -w, when not in Batch mode actual terminal dimensions can never be exceeded.
Note: Without the use of this command-line option, output width is always based on the terminal at which top was invoked whether or not in Batch mode.
-1  :Single/Separate-Cpu-States toggle Starts top with the last remembered Cpu States portion of the summary area reversed.  Either all cpu information will be displayed in a single line or each cpu will be displayed separately, depending on the state of the NUMA Node command toggle ('2').
See the `1' and '2' interactive commands for additional information.
2. SUMMARY Display Each of the following three areas are individually controlled through one or more interactive commands.  See topic 4b. SUMMARY AREA Commands for additional information regarding these provisions.
2a. UPTIME and LOAD Averages This portion consists of a single line containing: program or window name, depending on display mode current time and length of time since last boot total number of users system load avg over the last 1, 5 and 15 minutes
2b. TASK and CPU States This portion consists of a minimum of two lines.  In an SMP environment, additional lines can reflect individual CPU state percentages.
Line 1 shows total tasks or threads, depending on the state of the Threads-mode toggle.  That total is further classified as: running; sleeping; stopped; zombie
Line 2 shows CPU state percentages based on the interval since the last refresh.
As a default, percentages for these individual categories are displayed. Where two labels are shown below, those for more recent kernel versions are shown first. us, user    : time running un-niced user processes sy, system  : time running kernel processes ni, nice    : time running niced user processes id, idle    : time spent in the kernel idle handler wa, IO-wait : time waiting for I/O completion hi : time spent servicing hardware interrupts si : time spent servicing software interrupts st : time stolen from this vm by the hypervisor
In the alternate cpu states display modes, beyond the first tasks/threads line, an abbreviated summary is shown consisting of these elements: a    b     c    d %Cpu(s):  75.0/25.0  100[ ...
Where: a) is the `user' (us + ni) percentage; b) is the `system' (sy + hi + si) percentage; c) is the total; and d) is one of two visual graphs of those representations.  See topic 4b. SUMMARY AREA Commands and the `t' command for additional information on that special 4-way toggle.
2c. MEMORY Usage This portion consists of two lines which may express values in kibibytes (KiB) through exbibytes (EiB) depending on the scaling factor enforced with the `E' interactive command.
As a default, Line 1 reflects physical memory, classified as: total, free, used and buff/cache
Line 2 reflects mostly virtual memory, classified as: total, free, used and avail (which is physical memory)
The avail number on line 2 is an estimation of physical memory available for starting new applications, without swapping.  Unlike the free field, it attempts to account for readily reclaimable page cache and memory slabs.  It is available on kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as free.
In the alternate memory display modes, two abbreviated summary lines are shown consisting of these elements: a    b          c GiB Mem : 18.7/15.738   [ ... GiB Swap:  0.0/7.999    [ ...
Where: a) is the percentage used; b) is the total available; and c) is one of two visual graphs of those representations.
In the case of physical memory, the percentage represents the total minus the estimated avail noted above.  The `Mem' graph itself is divided between used and any remaining memory not otherwise accounted for by avail.  See topic 4b. SUMMARY AREA Commands and the `m' command for additional information on that special 4-way toggle.
This table may help in interpreting the scaled values displayed: KiB = kibibyte = 1024 bytes MiB = mebibyte = 1024 KiB = 1,048,576 bytes GiB = gibibyte = 1024 MiB = 1,073,741,824 bytes TiB = tebibyte = 1024 GiB = 1,099,511,627,776 bytes PiB = pebibyte = 1024 TiB = 1,125,899,906,842,624 bytes EiB = exbibyte = 1024 PiB = 1,152,921,504,606,846,976 bytes
3. FIELDS / Columns 3a. DESCRIPTIONS of Fields Listed below are top's available process fields (columns).  They are shown in strict ascii alphabetical order.  You may customize their position and whether or not they are displayable with the `f' or `F' (Fields Management) interactive commands.
Any field is selectable as the sort field, and you control whether they are sorted high-to-low or low-to-high.  For additional information on sort provisions see topic 4c. TASK AREA Commands, SORTING.
The fields related to physical memory or virtual memory reference `(KiB)' which is the unsuffixed display mode.  Such fields may, however, be scaled from KiB through PiB.  That scaling is influenced via the `e' interactive command or established for startup through a build option.
1. %CPU  --  CPU Usage The task's share of the elapsed CPU time since the last screen update, expressed as a percentage of total CPU time.
In a true SMP environment, if a process is multi-threaded and top is not operating in Threads mode, amounts greater than 100% may be reported.  You toggle Threads mode with the `H' interactive command.
Also for multi-processor environments, if Irix mode is Off, top will operate in Solaris mode where a task's cpu usage will be divided by the total number of CPUs.  You toggle Irix/Solaris modes with the `I' interactive command.
Note: When running in forest view mode (`V') with children collapsed (`v'), this field will also include the CPU time of those unseen children.  See topic 4c. TASK AREA Commands, CONTENT for more information regarding the `V' and `v' toggles.
2. %MEM  --  Memory Usage (RES) A task's currently resident share of available physical memory.
See `OVERVIEW, Linux Memory Types' for additional details.
3. CGNAME  --  Control Group Name The name of the control group to which a process belongs, or `-' if not applicable for that process.
This will typically be the last entry in the full list of control groups as shown under the next heading (CGROUPS).  And as is true there, this field is also variable width.
4. CGROUPS  --  Control Groups The names of the control group(s) to which a process belongs, or `-' if not applicable for that process.
Control Groups provide for allocating resources (cpu, memory, network bandwidth, etc.) among installation-defined groups of processes. They enable fine-grained control over allocating, denying, prioritizing, managing and monitoring those resources.
Many different hierarchies of cgroups can exist simultaneously on a system and each hierarchy is attached to one or more subsystems.  A subsystem represents a single resource.
Note: The CGROUPS field, unlike most columns, is not fixed-width. When displayed, it plus any other variable width columns will be allocated all remaining screen width (up to the maximum 512 characters).  Even so, such variable width fields could still suffer truncation.  See topic 5c. SCROLLING a Window for additional information on accessing any truncated data.
5. CODE  --  Code Size (KiB) The amount of physical memory currently devoted to executable code, also known as the Text Resident Set size or TRS.
6. COMMAND  --  Command Name or Command Line Display the command line used to start a task or the name of the associated program.  You toggle between command line and name with `c', which is both a command-line option and an interactive command.
When you've chosen to display command lines, processes without a command line (like kernel threads) will be shown with only the program name in brackets, as in this example: [kthreadd]
This field may also be impacted by the forest view display mode.  See the `V' interactive command for additional information regarding that mode.
Note: The COMMAND field, unlike most columns, is not fixed-width. When displayed, it plus any other variable width columns will be allocated all remaining screen width (up to the maximum 512 characters).  Even so, such variable width fields could still suffer truncation.  This is especially true for this field when command lines are being displayed (the `c' interactive command.)  See topic 5c. SCROLLING a Window for additional information on accessing any truncated data.
7. DATA  --  Data + Stack Size (KiB) The amount of private memory reserved by a process.  It is also known as the Data Resident Set or DRS.  Such memory may not yet be mapped to physical memory (RES) but will always be included in the virtual memory (VIRT) amount.
8. ENVIRON  --  Environment variables Display all of the environment variables, if any, as seen by the respective processes.  These variables will be displayed in their raw native order, not the sorted order you are accustomed to seeing with an unqualified `set'.
Note: The ENVIRON field, unlike most columns, is not fixed-width. When displayed, it plus any other variable width columns will be allocated all remaining screen width (up to the maximum 512 characters).  Even so, such variable width fields could still suffer truncation.  This is especially true for this field.  See topic 5c. SCROLLING a Window for additional information on accessing any truncated data.
9. Flags  --  Task Flags This column represents the task's current scheduling flags which are expressed in hexadecimal notation and with zeros suppressed.  These flags are officially documented in <linux/sched.h>.
10. GID  --  Group Id The effective group ID.
11. GROUP  --  Group Name The effective group name.
12. LXC  --  Lxc Container Name The name of the lxc container within which a task is running.  If a process is not running inside a container, a dash (`-') will be shown.
13. NI  --  Nice Value The nice value of the task.  A negative nice value means higher priority, whereas a positive nice value means lower priority.  Zero in this field simply means priority will not be adjusted in determining a task's dispatch-ability.
14. NU  --  Last known NUMA node A number representing the NUMA node associated with the last used processor (`P').  When -1 is displayed it means that NUMA information is not available.
See the `'2' and `3' interactive commands for additional NUMA provisions affecting the summary area.
15. OOMa  --  Out of Memory Adjustment Factor The value, ranging from -1000 to +1000, added to the current out of memory score (OOMs) which is then used to determine which task to kill when memory is exhausted.
16. OOMs  --  Out of Memory Score The value, ranging from 0 to +1000, used to select task(s) to kill when memory is exhausted.  Zero translates to `never kill' whereas 1000 means `always kill'.
17. P  --  Last used CPU (SMP) A number representing the last used processor.  In a true SMP environment this will likely change frequently since the kernel intentionally uses weak affinity.  Also, the very act of running top may break this weak affinity and cause more processes to change CPUs more often (because of the extra demand for cpu time).
18. PGRP  --  Process Group Id Every process is member of a unique process group which is used for distribution of signals and by terminals to arbitrate requests for their input and output.  When a process is created (forked), it becomes a member of the process group of its parent.  By convention, this value equals the process ID (see PID) of the first member of a process group, called the process group leader.
19. PID  --  Process Id The task's unique process ID, which periodically wraps, though never restarting at zero.  In kernel terms, it is a dispatchable entity defined by a task_struct.
This value may also be used as: a process group ID (see PGRP); a session ID for the session leader (see SID); a thread group ID for the thread group leader (see TGID); and a TTY process group ID for the process group leader (see TPGID).
20. PPID  --  Parent Process Id The process ID (pid) of a task's parent.
21. PR  --  Priority The scheduling priority of the task.  If you see `rt' in this field, it means the task is running under real time scheduling priority.
Under linux, real time priority is somewhat misleading since traditionally the operating itself was not preemptible.  And while the 2.6 kernel can be made mostly preemptible, it is not always so.
22. RES  --  Resident Memory Size (KiB) A subset of the virtual address space (VIRT) representing the non- swapped physical memory a task is currently using.  It is also the sum of the RSan, RSfd and RSsh fields.
It can include private anonymous pages, private pages mapped to files (including program images and shared libraries) plus shared anonymous pages.  All such memory is backed by the swap file represented separately under SWAP.
Lastly, this field may also include shared file-backed pages which, when modified, act as a dedicated swap file and thus will never impact SWAP.
23. RSan  --  Resident Anonymous Memory Size (KiB) A subset of resident memory (RES) representing private pages not mapped to a file.
24. RSfd  --  Resident File-Backed Memory Size (KiB) A subset of resident memory (RES) representing the implicitly shared pages supporting program images and shared libraries.  It also includes explicit file mappings, both private and shared.
25. RSlk  --  Resident Locked Memory Size (KiB) A subset of resident memory (RES) which cannot be swapped out.
26. RSsh  --  Resident Shared Memory Size (KiB) A subset of resident memory (RES) representing the explicitly shared anonymous shm*/mmap pages.
27. RUID  --  Real User Id The real user ID.
28. RUSER  --  Real User Name The real user name.
29. S  --  Process Status The status of the task which can be one of: D = uninterruptible sleep I = idle R = running S = sleeping T = stopped by job control signal t = stopped by debugger during trace Z = zombie
Tasks shown as running should be more properly thought of as ready to run  --  their task_struct is simply represented on the Linux run- queue.  Even without a true SMP machine, you may see numerous tasks in this state depending on top's delay interval and nice value.
30. SHR  --  Shared Memory Size (KiB) A subset of resident memory (RES) that may be used by other processes.  It will include shared anonymous pages and shared file- backed pages.  It also includes private pages mapped to files representing program images and shared libraries.
31. SID  --  Session Id A session is a collection of process groups (see PGRP), usually established by the login shell.  A newly forked process joins the session of its creator.  By convention, this value equals the process ID (see PID) of the first member of the session, called the session leader, which is usually the login shell.
32. SUID  --  Saved User Id The saved user ID.
33. SUPGIDS  --  Supplementary Group IDs The IDs of any supplementary group(s) established at login or inherited from a task's parent.  They are displayed in a comma delimited list.
Note: The SUPGIDS field, unlike most columns, is not fixed-width. When displayed, it plus any other variable width columns will be allocated all remaining screen width (up to the maximum 512 characters).  Even so, such variable width fields could still suffer truncation.  See topic 5c. SCROLLING a Window for additional information on accessing any truncated data.
34. SUPGRPS  --  Supplementary Group Names The names of any supplementary group(s) established at login or inherited from a task's parent.  They are displayed in a comma delimited list.
Note: The SUPGRPS field, unlike most columns, is not fixed-width. When displayed, it plus any other variable width columns will be allocated all remaining screen width (up to the maximum 512 characters).  Even so, such variable width fields could still suffer truncation.  See topic 5c. SCROLLING a Window for additional information on accessing any truncated data.
35. SUSER  --  Saved User Name The saved user name.
36. SWAP  --  Swapped Size (KiB) The formerly resident portion of a task's address space written to the swap file when physical memory becomes over committed.
37. TGID  --  Thread Group Id The ID of the thread group to which a task belongs.  It is the PID of the thread group leader.  In kernel terms, it represents those tasks that share an mm_struct.
38. TIME  --  CPU Time Total CPU time the task has used since it started.  When Cumulative mode is On, each process is listed with the cpu time that it and its dead children have used.  You toggle Cumulative mode with `S', which is both a command-line option and an interactive command.  See the `S' interactive command for additional information regarding this mode.
39. TIME+  --  CPU Time, hundredths The same as TIME, but reflecting more granularity through hundredths of a second.
40. TPGID  --  Tty Process Group Id The process group ID of the foreground process for the connected tty, or -1 if a process is not connected to a terminal.  By convention, this value equals the process ID (see PID) of the process group leader (see PGRP).
41. TTY  --  Controlling Tty The name of the controlling terminal.  This is usually the device (serial port, pty, etc.) from which the process was started, and which it uses for input or output.  However, a task need not be associated with a terminal, in which case you'll see `?' displayed.
42. UID  --  User Id The effective user ID of the task's owner.
43. USED  --  Memory in Use (KiB) This field represents the non-swapped physical memory a task is using (RES) plus the swapped out portion of its address space (SWAP).
44. USER  --  User Name The effective user name of the task's owner.
45. VIRT  --  Virtual Memory Size (KiB) The total amount of virtual memory used by the task.  It includes all code, data and shared libraries plus pages that have been swapped out and pages that have been mapped but not used.
46. WCHAN  --  Sleeping in Function This field will show the name of the kernel function in which the task is currently sleeping.  Running tasks will display a dash (`-') in this column.
47. nDRT  --  Dirty Pages Count The number of pages that have been modified since they were last written to auxiliary storage.  Dirty pages must be written to auxiliary storage before the corresponding physical memory location can be used for some other virtual page.
This field was deprecated with linux 2.6 and is always zero.
48. nMaj  --  Major Page Fault Count The number of major page faults that have occurred for a task.  A page fault occurs when a process attempts to read from or write to a virtual page that is not currently present in its address space.  A major page fault is when auxiliary storage access is involved in making that page available.
49. nMin  --  Minor Page Fault count The number of minor page faults that have occurred for a task.  A page fault occurs when a process attempts to read from or write to a virtual page that is not currently present in its address space.  A minor page fault does not involve auxiliary storage access in making that page available.
50. nTH  --  Number of Threads The number of threads associated with a process.
51. nsIPC  --  IPC namespace The Inode of the namespace used to isolate interprocess communication (IPC) resources such as System V IPC objects and POSIX message queues.
52. nsMNT  --  MNT namespace The Inode of the namespace used to isolate filesystem mount points thus offering different views of the filesystem hierarchy.
53. nsNET  --  NET namespace The Inode of the namespace used to isolate resources such as network devices, IP addresses, IP routing, port numbers, etc.
54. nsPID  --  PID namespace The Inode of the namespace used to isolate process ID numbers meaning they need not remain unique.  Thus, each such namespace could have its own `init/systemd' (PID #1) to manage various initialization tasks and reap orphaned child processes.
55. nsUSER  --  USER namespace The Inode of the namespace used to isolate the user and group ID numbers.  Thus, a process could have a normal unprivileged user ID outside a user namespace while having a user ID of 0, with full root privileges, inside that namespace.
56. nsUTS  --  UTS namespace The Inode of the namespace used to isolate hostname and NIS domain name.  UTS simply means "UNIX Time-sharing System".
57. vMj  --  Major Page Fault Count Delta The number of major page faults that have occurred since the last update (see nMaj).
58. vMn  --  Minor Page Fault Count Delta The number of minor page faults that have occurred since the last update (see nMin).
3b. MANAGING Fields After pressing the interactive command `f' or `F' (Fields Management) you will be presented with a screen showing: 1) the `current' window name; 2) the designated sort field; 3) all fields in their current order along with descriptions.  Entries marked with an asterisk are the currently displayed fields, screen width permitting.
•  As the on screen instructions indicate, you navigate among the fields with the Up and Down arrow keys.  The PgUp, PgDn, Home and End keys can also be used to quickly reach the first or last available field.
•  The Right arrow key selects a field for repositioning and the Left arrow key or the <Enter> key commits that field's placement.
•  The `d' key or the <Space> bar toggles a field's display status, and thus the presence or absence of the asterisk.
•  The `s' key designates a field as the sort field.  See topic 4c. TASK AREA Commands, SORTING for additional information regarding your selection of a sort field.
•  The `a' and `w' keys can be used to cycle through all available windows and the `q' or <Esc> keys exit Fields Management.
The Fields Management screen can also be used to change the `current' window/field group in either full-screen mode or alternate-display mode. Whatever was targeted when `q' or <Esc> was pressed will be made current as you return to the top display.  See topic 5. ALTERNATE-DISPLAY Provisions and the `g' interactive command for insight into `current' windows and field groups.
Note: Any window that has been scrolled horizontally will be reset if any field changes are made via the Fields Management screen.  Any vertical scrolled position, however, will not be affected.  See topic 5c. SCROLLING a Window for additional information regarding vertical and horizontal scrolling.
4. INTERACTIVE Commands Listed below is a brief index of commands within categories.  Some commands appear more than once  --  their meaning or scope may vary depending on the context in which they are issued.
4a. Global-Commands <Ent/Sp> ?, =, 0, A, B, d, E, e, g, h, H, I, k, q, r, s, W, X, Y, Z 4b. Summary-Area-Commands C, l, t, m, 1, 2, 3, 4, ! 4c. Task-Area-Commands Appearance:  b, J, j, x, y, z Content:     c, f, F, o, O, S, u, U, V, v Size:        #, i, n Sorting:     <, >, f, F, R 4d. Color-Mapping <Ret>, a, B, b, H, M, q, S, T, w, z, 0 - 7 5b. Commands-for-Windows -, _, =, +, A, a, g, G, w 5c. Scrolling-a-Window C, Up, Dn, Left, Right, PgUp, PgDn, Home, End 5d. Searching-in-a-Window L, &
4a. GLOBAL Commands The global interactive commands are always available in both full-screen mode and alternate-display mode.  However, some of these interactive commands are not available when running in Secure mode.
If you wish to know in advance whether or not your top has been secured, simply ask for help and view the system summary on the second line.
<Enter> or <Space>  :Refresh-Display These commands awaken top and following receipt of any input the entire display will be repainted.  They also force an update of any hotplugged cpu or physical memory changes.
Use either of these keys if you have a large delay interval and wish to see current status,
? | h  :Help There are two help levels available.  The first will provide a reminder of all the basic interactive commands.  If top is secured, that screen will be abbreviated.
Typing `h' or `?' on that help screen will take you to help for those interactive commands applicable to alternate-display mode.
=  :Exit-Display-Limits Removes restrictions on what is shown.  This command will reverse any `i' (idle tasks), `n' (max tasks) and `v' (hide children) commands that might be active.  It also provides for an exit from PID monitoring, User filtering, Other filtering, Locate processing and Combine Cpus mode.
Additionally, if the window has been scrolled it will be reset with this command.
0  :Zero-Suppress toggle This command determines whether zeros are shown or suppressed for many of the fields in a task window.  Fields like UID, GID, NI, PR or P are not affected by this toggle.
A  :Alternate-Display-Mode toggle This command will switch between full-screen mode and alternate-display mode.  See topic 5. ALTERNATE-DISPLAY Provisions and the `g' interactive command for insight into `current' windows and field groups.
B  :Bold-Disable/Enable toggle This command will influence use of the bold terminfo capability and alters both the summary area and task area for the `current' window.  While it is intended primarily for use with dumb terminals, it can be applied anytime.
Note: When this toggle is On and top is operating in monochrome mode, the entire display will appear as normal text.  Thus, unless the `x' and/or `y' toggles are using reverse for emphasis, there will be no visual confirmation that they are even on.
*  d | s  :Change-Delay-Time-interval You will be prompted to enter the delay time, in seconds, between display updates.
Fractional seconds are honored, but a negative number is not allowed.  Entering 0 causes (nearly) continuous updates, with an unsatisfactory display as the system and tty driver try to keep up with top's demands.  The delay value is inversely proportional to system loading, so set it with care.
If at any time you wish to know the current delay time, simply ask for help and view the system summary on the second line.
E  :Enforce-Summary-Memory-Scale in Summary Area With this command you can cycle through the available summary area memory scaling which ranges from KiB (kibibytes or 1,024 bytes) through EiB (exbibytes or 1,152,921,504,606,846,976 bytes).
If you see a `+' between a displayed number and the following label, it means that top was forced to truncate some portion of that number.  By raising the scaling factor, such truncation can be avoided.
e  :Enforce-Task-Memory-Scale in Task Area With this command you can cycle through the available task area memory scaling which ranges from KiB (kibibytes or 1,024 bytes) through PiB (pebibytes or 1,125,899,906,842,624 bytes).
While top will try to honor the selected target range, additional scaling might still be necessary in order to accommodate current values.  If you wish to see a more homogeneous result in the memory columns, raising the scaling range will usually accomplish that goal.  Raising it too high, however, is likely to produce an all zero result which cannot be suppressed with the `0' interactive command.
g  :Choose-Another-Window/Field-Group You will be prompted to enter a number between 1 and 4 designating the field group which should be made the `current' window.  You will soon grow comfortable with these 4 windows, especially after experimenting with alternate-display mode.
H  :Threads-mode toggle When this toggle is On, individual threads will be displayed for all processes in all visible task windows.  Otherwise, top displays a summation of all threads in each process.
I  :Irix/Solaris-Mode toggle When operating in Solaris mode (`I' toggled Off), a task's cpu usage will be divided by the total number of CPUs.  After issuing this command, you'll be told the new state of this toggle.
*  k  :Kill-a-task You will be prompted for a PID and then the signal to send.
Entering no PID or a negative number will be interpreted as the default shown in the prompt (the first task displayed).  A PID value of zero means the top program itself.
The default signal, as reflected in the prompt, is SIGTERM. However, you can send any signal, via number or name.
If you wish to abort the kill process, do one of the following depending on your progress: 1) at the pid prompt, type an invalid number 2) at the signal prompt, type 0 (or any invalid signal) 3) at any prompt, type <Esc>
q  :Quit
*  r  :Renice-a-Task You will be prompted for a PID and then the value to nice it to.
A positive nice value will cause a process to lose priority. Conversely, a negative nice value will cause a process to be viewed more favorably by the kernel.  As a general rule, ordinary users can only increase the nice value and are prevented from lowering it.
If you wish to abort the renice process, do one of the following depending on your progress: 1) at the pid prompt, type an invalid number 2) at the nice prompt, type <Enter> with no input 3) at any prompt, type <Esc>
W  :Write-the-Configuration-File This will save all of your options and toggles plus the current display mode and delay time.  By issuing this command just before quitting top, you will be able restart later in exactly that same state.
X  :Extra-Fixed-Width Some fields are fixed width and not scalable.  As such, they are subject to truncation which would be indicated by a `+' in the last position.
This interactive command can be used to alter the widths of the following fields:
field  default    field  default    field  default GID       5       GROUP     8       WCHAN    10 RUID      5       LXC       8       nsIPC    10 SUID      5       RUSER     8       nsMNT    10 UID       5       SUSER     8       nsNET    10 TTY       8       nsPID    10 USER      8       nsUSER   10 nsUTS    10
You will be prompted for the amount to be added to the default widths shown above.  Entering zero forces a return to those defaults.
If you enter a negative number, top will automatically increase the column size as needed until there is no more truncated data. You can accelerate this process by reducing the delay interval or holding down the <Space> bar.
Note: Whether explicitly or automatically increased, the widths for these fields are never decreased by top.  To narrow them you must specify a smaller number or restore the defaults.
Y  :Inspect-Other-Output After issuing the `Y' interactive command, you will be prompted for a target PID.  Typing a value or accepting the default results in a separate screen.  That screen can be used to view a variety of files or piped command output while the normal top iterative display is paused.
Note: This interactive command is only fully realized when supporting entries have been manually added to the end of the top configuration file.  For details on creating those entries, see topic 6b. ADDING INSPECT Entries.
Most of the keys used to navigate the Inspect feature are reflected in its header prologue.  There are, however, additional keys available once you have selected a particular file or command.  They are familiar to anyone who has used the pager `less' and are summarized here for future reference.
key      function =        alternate status-line, file or pipeline /        find, equivalent to `L' locate n        find next, equivalent to `&' locate next <Space>  scroll down, equivalent to <PgDn> b        scroll up, equivalent to <PgUp> g        first line, equivalent to <Home> G        last line, equivalent to <End>
Z  :Change-Color-Mapping This key will take you to a separate screen where you can change the colors for the `current' window, or for all windows.  For details regarding this interactive command see topic 4d. COLOR Mapping.
*  The commands shown with an asterisk (`*') are not available in Secure mode, nor will they be shown on the level-1 help screen.
4b. SUMMARY AREA Commands The summary area interactive commands are always available in both full-screen mode and alternate-display mode.  They affect the beginning lines of your display and will determine the position of messages and prompts.
These commands always impact just the `current' window/field group.  See topic 5. ALTERNATE-DISPLAY Provisions and the `g' interactive command for insight into `current' windows and field groups.
C  :Show-scroll-coordinates toggle Toggle an informational message which is displayed whenever the message line is not otherwise being used.  For additional information see topic 5c. SCROLLING a Window.
l  :Load-Average/Uptime toggle This is also the line containing the program name (possibly an alias) when operating in full-screen mode or the `current' window name when operating in alternate-display mode.
t  :Task/Cpu-States toggle This command affects from 2 to many summary area lines, depending on the state of the `1', `2' or `3' command toggles and whether or not top is running under true SMP.
This portion of the summary area is also influenced by the `H' interactive command toggle, as reflected in the total label which shows either Tasks or Threads.
This command serves as a 4-way toggle, cycling through these modes: 1. detailed percentages by category 2. abbreviated user/system and total % + bar graph 3. abbreviated user/system and total % + block graph 4. turn off task and cpu states display
When operating in either of the graphic modes, the display becomes much more meaningful when individual CPUs or NUMA nodes are also displayed.  See the the `1', `2' and `3' commands below for additional information.
m  :Memory/Swap-Usage toggle This command affects the two summary area lines dealing with physical and virtual memory.
This command serves as a 4-way toggle, cycling through these modes: 1. detailed percentages by memory type 2. abbreviated % used/total available + bar graph 3. abbreviated % used/total available + block graph 4. turn off memory display
1  :Single/Separate-Cpu-States toggle This command affects how the `t' command's Cpu States portion is shown.  Although this toggle exists primarily to serve massively- parallel SMP machines, it is not restricted to solely SMP environments.
When you see `%Cpu(s):' in the summary area, the `1' toggle is On and all cpu information is gathered in a single line.  Otherwise, each cpu is displayed separately as: `%Cpu0, %Cpu1, ...'  up to available screen height.
2  :NUMA-Nodes/Cpu-Summary toggle This command toggles between the `1' command cpu summary display (only) or a summary display plus the cpu usage statistics for each NUMA Node.  It is only available if a system has the requisite NUMA support.
3  :Expand-NUMA-Node You will be invited to enter a number representing a NUMA Node. Thereafter, a node summary plus the statistics for each cpu in that node will be shown until the `1', `2' or `4' command toggle is pressed.  This interactive command is only available if a system has the requisite NUMA support.
4  :Display-Cpus-Two-Abreast This command turns the `1' toggle Off for individual cpu display but prints the results two abreast.  It requires a terminal with a minimum width of 80 columns.  If a terminal's width is decreased below the minimum while top is running, top reverts to the normal `1' toggle Off state.
To avoid truncation when displaying detailed cpu statistcs, as opposed to the graphic representations, a minimum width of 165 columns would be required.
!  :Combine-Cpus-Mode This command toggle is intended for massively parallel SMP environments where, even with the `4' command toggle, not all processors can be displayed.  With each press of `!' the number of additional cpu's combined is doubled thus reducing the total number of cpu lines displayed.
For example, with the first press of `!' one additional cpu will be combined and displayed as `0-1, 2-3, ...' instead of the normal `%Cpu0, %Cpu1, %Cpu2, %Cpu3, ...'.  With a second `!' command toggle two additional cpus are combined and shown as `0-2, 3-5, ...'.  Then the third '!' press, combining four additional cpus, shows as `0-4, 5-9, ...', etc.
Such progression continues until individual cpus are again displayed and impacts both the `1' and `4' toggles (one or two columns).  Use the `=' command to exit Combine Cpus mode.
Note: If the entire summary area has been toggled Off for any window, you would be left with just the message line.  In that way, you will have maximized available task rows but (temporarily) sacrificed the program name in full-screen mode or the `current' window name when in alternate-display mode.
4c. TASK AREA Commands The task area interactive commands are always available in full-screen mode.
The task area interactive commands are never available in alternate-display mode if the `current' window's task display has been toggled Off (see topic 5. ALTERNATE-DISPLAY Provisions).
APPEARANCE of task window
J  :Justify-Numeric-Columns toggle Alternates between right-justified (the default) and left- justified numeric data.  If the numeric data completely fills the available column, this command toggle may impact the column header only.
j  :Justify-Character-Columns toggle Alternates between left-justified (the default) and right- justified character data.  If the character data completely fills the available column, this command toggle may impact the column header only.
The following commands will also be influenced by the state of the global `B' (bold enable) toggle.
b  :Bold/Reverse toggle This command will impact how the `x' and `y' toggles are displayed.  It may also impact the summary area when a bar graph has been selected for cpu states or memory usage via the `t' or `m' toggles.
x  :Column-Highlight toggle Changes highlighting for the current sort field.  If you forget which field is being sorted this command can serve as a quick visual reminder, providing the sort field is being displayed.  The sort field might not be visible because: 1) there is insufficient Screen Width 2) the `f' interactive command turned it Off
Note: Whenever Searching and/or Other Filtering is active in a window, column highlighting is temporarily disabled.  See the notes at the end of topics 5d. SEARCHING and 5e. FILTERING for an explanation why.
y  :Row-Highlight toggle Changes highlighting for "running" tasks.  For additional insight into this task state, see topic 3a. DESCRIPTIONS of Fields, the `S' field (Process Status).
Use of this provision provides important insight into your system's health.  The only costs will be a few additional tty escape sequences.
z  :Color/Monochrome toggle Switches the `current' window between your last used color scheme and the older form of black-on-white or white-on-black.  This command will alter both the summary area and task area but does not affect the state of the `x', `y' or `b' toggles.
CONTENT of task window
c  :Command-Line/Program-Name toggle This command will be honored whether or not the COMMAND column is currently visible.  Later, should that field come into view, the change you applied will be seen.
f | F  :Fields-Management These keys display a separate screen where you can change which fields are displayed, their order and also designate the sort field.  For additional information on these interactive commands see topic 3b. MANAGING Fields.
o | O  :Other-Filtering You will be prompted for the selection criteria which then determines which tasks will be shown in the `current' window. Your criteria can be made case sensitive or case can be ignored. And you determine if top should include or exclude matching tasks.
See topic 5e. FILTERING in a window for details on these and additional related interactive commands.
S  :Cumulative-Time-Mode toggle When Cumulative mode is On, each process is listed with the cpu time that it and its dead children have used.
When Off, programs that fork into many separate tasks will appear less demanding.  For programs like `init' or a shell this is appropriate but for others, like compilers, perhaps not. Experiment with two task windows sharing the same sort field but with different `S' states and see which representation you prefer.
After issuing this command, you'll be informed of the new state of this toggle.  If you wish to know in advance whether or not Cumulative mode is in effect, simply ask for help and view the window summary on the second line.
u | U  :Show-Specific-User-Only You will be prompted for the uid or name of the user to display. The -u option matches on  effective user whereas the -U option matches on any user (real, effective, saved, or filesystem).