TOP(1) User Commands TOP(1)NAMEtop - display Linux processes
SYNOPSIStop -hv|-bcHisS -d delay -n limit -u|U user -p pid -w [cols]
The traditional switches '-' and whitespace are optional.
DESCRIPTION
The top program provides a dynamic real-time view of a running
system. It can display system summary information as well as a
list of processes or threads currently being managed by the Linux
kernel. The types of system summary information shown and the
types, order and size of information displayed for processes are
all user configurable and that configuration can be made persis‐
tent across restarts.
The program provides a limited interactive interface for process
manipulation as well as a much more extensive interface for per‐
sonal configuration -- encompassing every aspect of its opera‐
tion. And while top is referred to throughout this document, you
are free to name the program anything you wish. That new name,
possibly an alias, will then be reflected on top's display and
used when reading and writing a configuration file.
OVERVIEW
Documentation
The remaining Table of Contents
1. COMMAND-LINE Options
2. 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
6. FILES
a. SYSTEM Configuration File
b. PERSONAL Configuration File
7. STUPID TRICKS Sampler
a. Kernel Magic
b. Bouncing Windows
c. The Big Bird Window
8. BUGS, 9. HISTORY Former top, 10. AUTHOR, 11. 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.
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 keys are accepted for compatibility:
key equivalents
Up alt + \ or alt + k
Down alt + / or alt + j
Left alt + < or alt + h
Right alt + > or alt + l (lower case L)
PgUp alt + Up
PgDn alt + Down
Home alt + Left
End alt + Right
When you start top for the first time, you'll be presented with
these traditional screen elements: 1) Summary Area; 2) Fields/Col‐
umns Header; 3) Task Area. These areas 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 expla‐
nation.
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.
Startup Defaults
The following startup defaults assume no configuration file, thus
no user customizations. Even so, items shown with an asterisk
(´*´) could be overridden through the command-line. All are
explained in detail in the sections that follow.
Global-defaults
'A' - Alt display Off (full-screen)
* 'd' - Delay time 3.0 seconds
* 'H' - Threads mode Off (summarize as tasks)
'I' - Irix mode On (no, 'solaris' smp)
* 'p' - PID monitoring Off (show all processes)
* 's' - Secure mode Off (unsecured)
'B' - Bold enable On (yes, bold globally)
Summary-Area-defaults
'l' - Load Avg/Uptime On (thus program name)
't' - Task/Cpu states On (1+1 lines, see '1')
'm' - Mem/Swap usage On (2 lines worth)
'1' - Single Cpu On (thus 1 line if smp)
Task-Area-defaults
'b' - Bold hilite On (not 'reverse')
* 'c' - Command line Off (name, not cmdline)
* 'i' - Idle tasks On (show all tasks)
'R' - Reverse sort On (pids high-to-low)
* 'S' - Cumulative time Off (no, dead children)
* 'u' - User filter Off (show euid only)
* 'U' - User filter Off (show any uid)
'x' - Column hilite Off (no, sort field)
'y' - Row hilite On (yes, running tasks)
'z' - color/mono Off (no, colors)
1. COMMAND-LINE Options
The command-line syntax for top consists of:
-hv | -bcHisS -d delay -n limit -u|U user | -p pid -w [cols]
The typically mandatory switches ('-') 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 visa versa. See the 'c' inter‐
active command for additional information.
-d : Delay-time interval as: -d ss.tt (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 infor‐
mation on 'Secure mode' see topic 6a. SYSTEM Configuration
File.
-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 infor‐
mation regarding this toggle see topic 4c. TASK AREA Com‐
mands, SIZE.
-n : Number-of-iterations limit as: -n number
Specifies the maximum number of iterations, or frames, top
should produce before ending.
-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
and restart top-- just issue any of these interactive com‐
mands: '=', 'u' or 'U'.
The 'p', 'u' and 'U' command-line options are mutually exclu‐
sive.
-s : Secure-mode operation
Starts top with secure mode forced, even for root. This mode
is far better controlled through the system configuration
file (see topic 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).
The 'p', 'u' and 'U' command-line options are mutually exclu‐
sive.
-w : Output-width-override as: -w [ number ]
In 'Batch' mode, when used without an argument top will for‐
mat output using the COLUMNS= and LINES= environment vari‐
ables, 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.
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 provi‐
sions.
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 envi‐
ronment, additional lines can reflect individual CPU state per‐
centages.
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. 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
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
2c. MEMORY Usage
This portion consists of two lines which may express values in
kibibytes (KiB), mebibytes (MiB) or gibibytes (GiB) depending on
the amount of currently installed physical memory.
Line 1 reflects physical memory, classified as:
total, used, free, buffers
Line 2 reflects virtual memory, classified as:
total, used, free, cached
3. FIELDS / Columns
3a. DESCRIPTIONS of Fields
Listed below are top's available process fields (columns). They
are shown in 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 infor‐
mation on sort provisions see topic 4c. TASK AREA Commands, SORT‐
ING.
1. 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 sub‐
systems. 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 col‐
umns will be allocated all remaining screen width (up to the
maximum 512 characters).
2. CODE -- Code Size (KiB)
The amount of physical memory devoted to executable code, also
known as the 'text resident set' size or TRS.
3. 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:
[ mdrecoveryd ]
Either form of display is subject to potential truncation if
it's too long to fit in this field's current width. That
width depends upon other fields selected, their order and the
current screen width.
This field may also be impacted by the 'forest view' display
mode. See the 'V' interactive command for additional informa‐
tion regarding that mode.
Note: The 'COMMAND' field, unlike most columns, is not fixed-
width. When displayed, it plus any other variable width col‐
umns will be allocated all remaining screen width (up to the
maximum 512 characters).
4. %CPU -- CPU Usage
The task's share of the elapsed CPU time since the last screen
update, expressed as a percentage of total CPU time. In a
true SMP environment, if 'Irix mode' is Off, top will operate
in 'Solaris mode' where a task's cpu usage will be divided by
the total number of CPUs. You toggle 'Irix/Solaris' modes
with the 'I' interactive command.
5. DATA -- Data + Stack Size (KiB)
The amount of physical memory devoted to other than executable
code, also known as the 'data resident set' size or DRS.
6. 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>.
7. GID -- Group Id
The effective group ID.
8. GROUP -- Group Name
The effective group name.
9. %MEM -- Memory Usage (RES)
A task's currently used share of available physical memory.
10. 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.
11. nDRT -- Dirty Pages Count
The number of pages that have been modified since they were
last written to auxiliary storage. Dirty pages must be writ‐
ten to auxiliary storage before the corresponding physical
memory location can be used for some other virtual page.
12. 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.
13. 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.
14. nTH -- Number of Threads
The number of threads associated with a process.
15. P -- Last used CPU (SMP)
A number representing the last used processor. In a true SMP
environment this will likely change frequently since the ker‐
nel intentionally uses weak affinity. Also, the very act of
running top may break this weak affinity and cause more pro‐
cesses to change CPUs more often (because of the extra demand
for cpu time).
16. 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 cre‐
ated (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.
17. PID -- Process Id
The task's unique process ID, which periodically wraps, though
never restarting at zero. In kernel terms, it is a dispatch‐
able 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).
18. PPID -- Parent Process Id
The process ID (pid) of a task's parent.
19. PR -- Priority
The scheduling priority of the task. If you see 'rt' in this
field, it means the task is running under 'real time' schedul‐
ing priority.
Under linux, real time priority is somewhat misleading since
traditionally the operating itself was not preemptable. And
while the 2.6 kernel can be made mostly preemptable, it is not
always so.
20. RES -- Resident Memory Size (KiB)
The non-swapped physical memory a task has used.
21. RUID -- Real User Id
The real user ID.
22. RUSER -- Real User Name
The real user name.
23. S -- Process Status
The status of the task which can be one of:
'D' = uninterruptible sleep
'R' = running
'S' = sleeping
'T' = traced or stopped
'Z' = zombie
Tasks shown as running should be more properly thought of as
'ready to run' -- their task_struct is simply represented on
the Linux run-queue. Even without a true SMP machine, you may
see numerous tasks in this state depending on top's delay
interval and nice value.
24. SHR -- Shared Memory Size (KiB)
The amount of shared memory available to a task, not all of
which is typically resident. It simply reflects memory that
could be potentially shared with other processes.
25. SID -- Session Id
A session is a collection of process groups (see PGRP), usu‐
ally 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.
26. SUID -- Saved User Id
The saved user ID.
27. 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 col‐
umns will be allocated all remaining screen width (up to the
maximum 512 characters).
28. 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 col‐
umns will be allocated all remaining screen width (up to the
maximum 512 characters).
29. SUSER -- Saved User Name
The saved user name.
30. SWAP -- Swapped Size (KiB)
The non-resident portion of a task's address space.
31. 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 repre‐
sents those tasks that share an 'mm_struct'.
32. 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.
33. TIME+ -- CPU Time, hundredths
The same as 'TIME', but reflecting more granularity through
hundredths of a second.
34. TPGID -- Tty Process Group Id
The process group ID of the foreground process for the con‐
nected tty, or -1 if a process is not connected to a terminal.
By convention, this value equals the process ID (see PID) of
the the process group leader (see PGRP).
35. 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.
36. UID -- User Id
The effective user ID of the task's owner.
37. USER -- User Name
The effective user name of the task's owner.
38. 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.
39. WCHAN -- Sleeping in Function
Depending on the availability of the kernel link map ('Sys‐
tem.map'), this field will show the name or the address of the
kernel function in which the task is currently sleeping. Run‐
ning tasks will display a dash ('-') in this column.
By displaying this field, top's own working set could be
increased by over 700Kb, depending on the kernel version.
Should that occur, your only means of reducing that overhead
will be to stop and restart top.
Note: The 'WCHAN' field, unlike most columns, is not fixed-
width. When displayed, it plus any other variable width col‐
umns will be allocated all remaining screen width (up to the
maximum 512 characters).
3b. MANAGING Fields
After pressing the interactive command 'f' or 'F' (Fields Manage‐
ment) you will be presented with a screen showing: 1) the ´cur‐
rent´ 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 per‐
mitting.
o As the on screen instructions indicate, you navigate among
the fields with the Up and Down arrow keys. The PgUp,
PgDn, Home and End keys can also be used to quickly reach
the first or last available field.
o The Right arrow key selects a field for repositioning and
the Left arrow key or the <Enter> key commits that field's
placement.
o The 'd' key or the <Space> bar toggles a field's display
status, and thus the presence or absence of the asterisk.
o The 's' key designates a field as the sort field. See
topic 4c. TASK AREA Commands, SORTING for additional infor‐
mation regarding your selection of a sort field.
o The 'a' and 'w' keys can be used to cycle through all
available windows and the 'q' or <Esc> keys exit Fields
Management.
The Fields Management screen can also be used to change the ´cur‐
rent´ window/field group in either full-screen mode or alter‐
nate-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> ?, =, A, B, d, g, h, H, I, k, q, r, s, W, Z
4b. Summary-Area-Commands
C, l, t, 1, m
4c. Task-Area-Commands
Appearance: b, x, y, z
Content: c, f, F, S, u, U, 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 pro‐
vide 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-dis‐
play mode.
´=´ :Exit-Task-Limits
Removes restrictions on which tasks are shown. This com‐
mand will reverse any 'i' (idle tasks) and 'n' (max tasks)
commands that might be active. It also provides for an
'exit' from pid monitoring and user filtering. See the
'-p' command-line option for a discussion of PID monitoring
and the 'U' or 'u' interactive commands regarding user fil‐
tering.
Additionally, any window that has been scrolled will be
reset with this command. See topic 5c. SCROLLING a Window
for additional information regarding vertical and horizon‐
tal scrolling.
When operating in alternate-display mode this command has a
broader meaning.
´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 mono‐
chrome 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 sec‐
ond line.
´g´ :Choose-Another-Window/Field-Group
You will be prompted to enter a number between 1 and 4 des‐
ignating the field group which should be made the ´current´
window. You will soon grow comfortable with these 4 win‐
dows, especially after experimenting with alternate-display
mode.
´H´ :Threads-mode toggle
When this toggle is On, individual threads will be dis‐
played for all processes in all visible task windows. Oth‐
erwise, 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.
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 fol‐
lowing depending on your progress:
1) at the pid prompt, just press <Enter>
2) at the signal prompt, type 0
´q´ :Quit
* ´r´ :Renice-a-Task
You will be prompted for a PID and then the value to nice
it to. Entering a positive value will cause a process to
lose priority. Conversely, a negative value will cause a
process to be viewed more favorably by the kernel.
´W´ :Write-the-Configuration-File
This will save all of your options and toggles plus the
current display mode and delay time. By issuing this com‐
mand just before quitting top, you will be able restart
later in exactly that same state.
´Z´ :Change-Color-Mapping
This key will take you to a separate screen where you can
change the colors for the ´current´ window, or for all win‐
dows. 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.
´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 ´cur‐
rent´ 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' toggle 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'.
´1´ :Single/Separate-Cpu-States toggle
This command affects how the 't' command's Cpu States por‐
tion 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.
´m´ :Memory/Swap-Usage toggle
This command affects the two summary area lines dealing
with physical and virtual memory.
Note: If the entire summary area has been toggled Off for any win‐
dow, you would be left with just the message line. In that way,
you will have maximized available task rows but (temporarily) sac‐
rificed the program name in full-screen mode or the ´current´ win‐
dow name when in alternate-display mode.
4c. TASK AREA Commands
The task area interactive commands are always available in
full-screen mode.
The task area interactive commands are never available in alter‐
nate-display mode if the ´current´ window's task display has been
toggled Off (see topic 5. ALTERNATE-DISPLAY Provisions).
APPEARANCE of task window
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. Further, it will only be available when at
least one of those toggles is On.
´x´ :Column-Highlight toggle
Changes highlighting for the current sort field. 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´ | ´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 inter‐
active commands see topic 3b. MANAGING Fields.
´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 rep‐
resentation 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, effec‐
tive, saved, or filesystem).
Thereafter, in that task window only matching users will be
shown, or possibly no processes will be shown. Different
task windows can can be used to filter different users.
Later, if you wish to monitor all tasks again in the ´cur‐
rent´ 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 commamd 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.
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 granu‐
larity 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 win‐
dow'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 dis‐
play. 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 cur‐
rently 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 vis‐
ible because:
1) there is insufficient Screen Width
2) the 'f' interactive command turned it Off
´<´ :Move-Sort-Field-Left
Moves the sort column to the left unless the current sort
field is the first field being displayed.
´>´ :Move-Sort-Field-Right
Moves the sort column to the right unless the current sort
field is the last field being displayed.
The following interactive commands will always be honored
whether or not the current sort field is visible.
´f´ | ´F´ :Fields-Management
These keys display a separate screen where you can change
which field is used as the sort column, among other func‐
tions. This can be a convenient way to simply verify the
current sort field, when running top with column highlight‐
ing turned Off.
´R´ :Reverse/Normal-Sort-Field toggle
Using this interactive command you can alternate between
high-to-low and low-to-high sorts.
Note: Field sorting uses internal values, not those in column
display. Thus, the TTY and WCHAN fields will violate strict
ASCII collating sequence.
4d. COLOR Mapping
When you issue the 'Z' interactive command, you will be presented
with a separate screen. That screen can be used to change the
colors in just the ´current´ window or in all four windows before
returning to the top display.
The following interactive commands are available.
4 upper case letters to select a target
8 numbers to select a color
normal toggles available
'B' :bold disable/enable
'b' :running tasks "bold"/reverse
'z' :color/mono
other commands available
'a'/'w' :apply, then go to next/prior
<Enter> :apply and exit
'q' :abandon current changes and exit
If you use 'a' or 'w' to cycle the targeted window, you will have
applied the color scheme that was displayed when you left that
window. You can, of course, easily return to any window and reap‐
ply 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 dis‐
play 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 config‐
urable task area.
In alternate-display mode, those 4 underlying field groups can
now be made visible simultaneously, or can be turned Off indi‐
vidually at your command.
The summary area will always exist, even if it's only the mes‐
sage line. At any given time only one summary area can be dis‐
played. 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' interac‐
tive 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 dis‐
play(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-(re-balance)-Window(s)
The '=' key forces the ´current´ window's task display to
be visible. It also reverses any 'i' (idle tasks), 'n'
(max tasks) and 'u'/'U' (user filter) commands that might
be active. Also, if the window had been scrolled, it will
be reset with this command. See topic 5c. SCROLLING a Win‐
dow for additional information regarding vertical and hori‐
zontal scrolling.
The '+' key does the same for all windows. The four task
displays will reappear, evenly balanced. They will also
have retained any customizations you had previously
applied, except for the 'i' (idle tasks), 'n' (max tasks),
'u'/'U' (user filter) and scrolling interactive commands.
* ´A´ :Alternate-Display-Mode toggle
This command will switch between full-screen mode and
alternate-display mode.
The first time you issue this command, all four task dis‐
plays 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
´current´ window using either key.
Assuming the window name is visible (you have not toggled
'l' Off), whenever the ´current´ window name loses its
emphasis/color, that's a reminder the task display is Off
and many commands will be restricted.
* ´g´ :Choose-Another-Window/Field-Group
You will be prompted to enter a number between 1 and 4 des‐
ignating the field group which should be made the ´current´
window.
In full-screen mode, this command is necessary to alter the
´current´ window. In alternate-display mode, it is simply
a less convenient alternative to the 'a' and 'w' commands.
´G´ :Change-Window/Field-Group-Name
You will be prompted for a new name to be applied to the
´current´ window. It does not require that the window name
be visible (the 'l' toggle to be On).
* The interactive commands shown with an asterisk (´*´) have use
beyond alternate-display mode.
´=', 'A', 'g' are always available
´a', 'w' act the same with color mapping
and fields management
5c. SCROLLING a Window
Typically a task window is a partial view into a systems's total
tasks/threads which shows only some of the available fields/col‐
umns. With these scrolling keys, you can move that view verti‐
cally 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 unex‐
pected results initially.
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.
"scroll coordinates: y = n/n (tasks), x = n/n (fields)"
The coordinates shown as n/n are relative to the upper left
corner of the ´current´ window.
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 ´cur‐
rent´ window's task display has been toggled Off.
5d. SEARCHING in a Window
You can use these interactive commands to locate a task row con‐
taining 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 col‐
umn. 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 verti‐
cally 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 ´cur‐
rent´ window's task display has been toggled Off.
Note: Whenever a search key is typed, top forces idle tasks On and
user filtering Off to ensure that every task is encountered. See
the 'i' and 'u/U' interactive commands for additional information
on how displayed tasks might be filtered.
6. FILES
6a. SYSTEM Configuration File
The presence of this file will influence which version of the
'help' screen is shown to an ordinary user. More importantly, it
will limit what ordinary users are allowed to do when top is run‐
ning. They will not be able to issue the following commands.
k Kill a task
r Renice a task
d or s Change delay/sleep interval
The system configuration file is not created by top. Rather, you
create this file manually and place it in the /etc directory. Its
name must be 'toprc' and must have no leading '.' (period). It
must have only two lines.
Here is an example of the contents of /etc/toprc:
s # line 1: 'secure' mode switch
5.0 # line 2: 'delay' interval in seconds
6b. PERSONAL Configuration File
This file is written as '$HOME/.your-name-4-top' + 'rc'. Use the
'W' interactive command to create it or update it.
Here is the general layout:
global # line 1: the program name/alias notation
" # line 2: id,altscr,irixps,delay,curwin
per ea # line a: winname,fieldscur
window # line b: winflags,sortindx,maxtasks
" # line c: summclr,msgsclr,headclr,taskclr
If the $HOME variable is not present, top will try to write the
personal configuration file to the current directory, subject to
permissions.
7. STUPID TRICKS Sampler
Many of these 'tricks' work best when you give top a scheduling
boost. So plan on starting him with a nice value of -10, assuming
you've got the authority.
7a. Kernel Magic
For these stupid tricks, top needs full-screen mode.
o The user interface, through prompts and help, intentionally
implies that the delay interval is limited to tenths of a sec‐
ond. However, you're free to set any desired delay. If you
want to see Linux at his scheduling best, try a delay of .09
seconds or less.
For this experiment, under x-windows open an xterm and maximize
it. Then do the following:
. provide a scheduling boost and tiny delay via:
nice -n -10 top-d.09
. keep sorted column highlighting Off so as to
minimize path length
. turn On reverse row highlighting for emphasis
. try various sort columns (TIME/MEM work well),
and normal or reverse sorts to bring the most
active processes into view
What you'll see is a very busy Linux doing what he's always
done for you, but there was no program available to illustrate
this.
o Under an xterm using 'white-on-black' colors, on top's Color
Mapping screen set the task color to black and be sure that
task 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.
o Delete the existing rcfile, or create a new symlink. Start
this new version then type 'T' (a secret key, see topic 4c.
Task Area 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.
o With 3 or 4 task displays visible, pick any window other than
the last and turn idle processes Off using the 'i' command tog‐
gle. Depending on where you applied 'i', sometimes several
task displays are bouncing and sometimes it's like an accor‐
dion, as top tries his best to allocate space.
o Set each window's summary lines differently: one with no memory
('m'); another with no states ('t'); maybe one with nothing at
all, just the message line. Then hold down 'a' or 'w' and
watch a variation on bouncing windows -- hopping windows.
o Display all 4 windows and for each, in turn, set idle processes
to Off using the 'i' command toggle. You've just entered the
"extreme bounce" zone.
7c. The Big Bird Window
This stupid trick also requires alternate-display mode.
o Display all 4 windows and make sure that 1:Def is the ´current´
window. Then, keep increasing window size with the 'n' inter‐
active command until all the other task displays are "pushed
out of the nest".
When they've all been displaced, toggle between all visi‐
ble/invisible windows using the '_' command toggle. Then pon‐
der this:
is top fibbing or telling honestly your imposed truth?
8. BUGS
To report bugs, follow the instructions at:
http://www.debian.org/Bugs/Reporting
9. HISTORY Former top
The original top was written by Roger Binns, based on Branko
Lankester's <lankeste@fwi.uva.nl> ps program.
Robert Nation <nation@rocket.sanders.lockheed.com> adapted it for
the proc file system.
Helmut Geyer <Helmut.Geyer@iwr.uni-heidelberg.de> added support
for configurable fields.
Plus many other individuals contributed over the years.
10. AUTHOR
This entirely new and enhanced replacement was written by:
Jim Warner, <james.warner@comcast.net>
With invaluable help from:
Craig Small, <csmall@enc.com.au>
Albert Cahalan, <albert@users.sf.net>
11. SEE Alsofree(1), ps(1), uptime(1), atop(1), slabtop(1), vmstat(8), w(1).
procps-ng April 2011 TOP(1)