TOP - Linux command

by Little Bear @6 มิ.ย. 50 03:03 ( IP : 61...80 ) | Tags : Ubuntu , Linux

TOP(1)                  Linux User's Manual

TOP(1) NAME      top - display Linux tasks     


      top -hv | -bcisS -d delay -n iterations -p pid [, pid ...]

          The traditional switches '-' and whitespace are optional.


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  tasks currently  being managed by the Linux kernel.  The types of system summary information shown and the types, order  and  size  of  information displayed  for  tasks  are all user configurable and that configuration can be made persistent across restarts.

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


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

When you start top for the first time, you'll  be  presented  with  the traditional  screen  elements: 1) Summary Area; 2) Message/Prompt Line; 3) Columns Header; 4) Task Area.  There will, however, be some  differences when compared to the former top.


SummaryArea: There is no highlighting for load/uptime and only val- ues are highlighted for other elements.

TaskArea: Tasks running (or ready to run) will be highlighted,  and bold is only one way of emphasizing such processes.


SummaryArea: The program name is shown, perhaps a symlink or alias. The Cpu(s) state label hints at  other  possibilities.  The    memory stats use a lower case 'k'.

ColumnsHeader: Will show a new field and some changed labels.  More new fields will be found as you customize your top.

Note: the width of top's display will  be  limited  to  512  positions. Displaying  all    fields    requires  a  minimum  of  160 characters.  The remaining width could be used for the 'Command' column.


The command-line syntax for top consists of:

-hv | -bcisS -d delay -n iterations -p pid [,pid...]

The typically mandatory switches ('-') and  even  whitespace  are  com- pletely optional.

-b : Batch mode operation

Starts top in 'Batch mode', which could be useful for sending out- put 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' interactive command for  addi- tional information.

-d : Delay time interval as:  -d (seconds.tenths)

Specifies the delay between screen updates, and overrides the cor- responding value in  one's    personal  configuration  file  or  the startup  default.    Later  this can be changed with the 'd' or 's' interactive commands.

Fractional seconds are honored,  but  a  negative  number  is  not 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 5a. SYSTEM Configuration File.

-h : Help

Show library version and the usage prompt, then quit.

-i : Idle Processes toggle

Starts top with the last remembered 'i' state reversed.  When this toggle  is    Off,  tasks that are idled or zombied will not be dis- played.

-n : Number of iterations limit as:  -n number

Specifies the maximum number of iterations, or frames, top    should produce before ending.

-u : Monitor by user as:  -u somebody

Monitor only processes with an effective UID or user name matching that given.

-U : Monitor by user as:  -U somebody

Monitor only processes with a  UID    or  user  name    matching  that given.  This matches real, effective, saved, and filesystem UIDs.

-p : Monitor PIDs as:  -pN1 -pN2 ...  or  -pN1, N2 [,...]

Monitor only processes with specified process  IDs.  This    option can  be given up to 20 times, or you can provide a comma delimited list with up to 20 pids.  Co-mingling both approaches  is  permit- ted.

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 the '=' interactive command.

-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 5. FILES).

-S : Cumulative time mode toggle

Starts  top  with  the  last  remembered 'S' state reversed.  When 'Cumulative 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.

-v : Version

Show library version and the usage prompt, then quit.

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