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Autor

Heiki Nooremäe

Sissejuhatus

In most Unix-like operating systems, the top command is a system monitor tool that produces a frequently-updated list of processes. By default, the processes are ordered by percentage of CPU usage, with only the "top" CPU consumers shown. The top command shows how much processing power and memory are being used, as well as other information about the running processes. Some versions of top allow extensive customization of the display, such as choice of columns or sorting method.

The top command is useful for system administrators, as it shows which users and processes are consuming the most system resources at any given time.

It is also possible to redirect the output of top to a text file.

Ajalugu

The top command was inspired by the monitor process/topcpu command found in the VMS operating system. William LeFebvre wrote the first implementation of top in April 1984 for BSD 4.1 while a graduate student at Rice University. It was released as an Open source project under the BSD license, which allowed it to be included in numerous proprietary BSD and UNIX operating systems.

The top command has been reimplemented several times for different operating systems and under different licenses. In AIX an advanced top version was introduced in AIX 4.3 in 1999 called topas.

The first top for Linux was written by Roger Binns; the most recent and common Linux version is a full-color windowed implementation by James C. Warner that ships with the procps package.

Top

Some options to top are listed below.

-d: Delay time interval as:  -d ss.tt (seconds. tenths)
	    Specifies the delay between screen updates
-u: Monitor by user as:  -u somebody
	    Monitor only processes with an effective UID or user name matching
	    That given.
-c: RUSER -- Real User Name. The real user name of the task's owner.


-C: color
	    Turn off the use of color in the display.

-I: idle-procs
	    Do  not  display  idle processes.

-S: system-procs
              Show system processes in the  display.

-T: tag-names
              List all available color tags and the current set of tests  used
              for color highlighting, then exit.

-a: all
              Show  all  processes for as long as possible.

-b: batch
              Use  "batch" mode.  In this mode, all input from the terminal is
              ignored.

-c: full-commands
              Show the full command line for each process.

-i: interactive
              Use "interactive" mode.  In this mode, any input is  immediately
              read  for processing.

-q: quick
              Renice  top to -20 so that it will run faster.

-t: threads
              Show individual threads on separate lines.



-v: version
              Write version number information to  stderr  then  exit  immedi-
              ately.


-m mode: mode=mode
              Start  the display in an alternate mode.

-o field: sort-order=field
              Sort the process display area on the specified field.

-s time: delay=time
              Set  the  delay  between  screen  updates  to time seconds.

-U username: user=username
              Show only those processes owned by username.

Kasutatud kirjandus

http://en.wikipedia.org/wiki/Top_(Unix)