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top - display and update information about the top cpu processes



        top - display and update information about the top cpu processes


        top  [ -SbiInqutv ] [ -dcount ] [ -stime ] [ -ofield ] [ -Uusername ] [
        number ]


        Top displays the top processes on the system and  periodically  updates
        this  information.   If standard output is an intelligent terminal (see
        below) then as many processes as will fit on the  terminal  screen  are
        displayed  by  default.   Otherwise,  a  good  number of them are shown
        (around 20).  Raw cpu percentage is used to  rank  the  processes.   If
        number  is  given,  then  the  top  number  processes will be displayed
        instead of the default.
        Top makes a distinction between terminals that support  advanced  capa‐
        bilities and those that do not.  This distinction affects the choice of
        defaults for certain options.  In the remainder of  this  document,  an
        "intelligent"  terminal  is  one that supports cursor addressing, clear
        screen, and clear to end of line.  Conversely, a "dumb" terminal is one
        that  does  not  support  such features.  If the output of top is redi‐
        rected to a file, it acts as if it were being run on a dumb terminal.


        -S     Show system processes in the  display.   Normally,  system  pro‐
               cesses  such  as  the pager and the swapper are not shown.  This
               option makes them visible.
        -b     Use "batch" mode.  In this mode, all input from the terminal  is
               ignored.  Interrupt characters (such as ^C and ^\) still have an
               effect.  This is the default on a dumb  terminal,  or  when  the
               output is not a terminal.
        -i     Use  "interactive" mode.  In this mode, any input is immediately
               read for processing.  See the section on "Interactive Mode"  for
               an  explanation of which keys perform what functions.  After the
               command is processed, the screen will  immediately  be  updated,
               even  if  the  command  was  not  understood.   This mode is the
               default when standard output is an intelligent terminal.
        -I     Do not display idle processes.  By default,  top  displays  both
               active and idle processes.
        -t     Do not display the top process.
        -n     Use  "non-interactive" mode.  This is identical to "batch" mode.
        -q     Renice top to -20 so that it will run faster.  This can be  used
               when  the system is being very sluggish to improve the possibil‐
               ity of discovering the problem.  This option can only be used by
        -u     Do not take the time to map uid numbers to usernames.  Normally,
               top will read as much of the file "/etc/passwd" as is  necessary
               to  map  all the user id numbers it encounters into login names.
               This option disables all that, while possibly decreasing  execu‐
               tion  time.  The uid numbers are displayed instead of the names.
        -v     Write version number information to  stderr  then  exit  immedi‐
               ately.   No  other  processing  takes  place when this option is
               used.  To see current revision information while top is running,
               use the help command "?".
               Show only count displays, then exit.  A display is considered to
               be one update of the screen.  This option  allows  the  user  to
               select  the  number of displays he wants to see before top auto‐
               matically exits.  For intelligent terminals, no upper  limit  is
               set.  The default is 1 for dumb terminals.
        -stime Set  the  delay  between  screen  updates  to time seconds.  The
               default delay between updates is 2 seconds.
               Sort the process display area on the specified field.  The field
               name  is  the  name  of the column as seen in the output, but in
               lower case.  Likely values are "cpu", "size", "res", and "time",
               but  may vary on different operating systems.  Note that not all
               operating systems support this option.
               Show only those processes owned by username.  This  option  cur‐
               rently  only  accepts usernames and will not understand uid num‐
        Both count and number fields can be specified as "infinite", indicating
        that  they  can  stretch  as  far as possible.  This is accomplished by
        using any proper prefix  of  the  keywords  "infinity",  "maximum",  or
        "all".   The  default for count on an intelligent terminal is, in fact,
        The environment variable TOP is examined for options before the command
        line  is  scanned.  This enables a user to set his or her own defaults.
        The number of processes to display can also be specified in  the  envi‐
        ronment variable TOP.  The options -I, -S, -u, and -t are actually tog‐
        gles.  A second specification of any of these options will  negate  the
        first.   Thus  a  user who has the environment variable TOP set to "-I"
        may use the command "top -I" to see idle processes.
        When top is running in "interactive mode", it reads commands  from  the
        terminal and acts upon them accordingly.  In this mode, the terminal is
        put in "CBREAK", so that a character will be processed as soon as it is
        typed.   Almost  always, a key will be pressed when top is between dis‐
        plays; that is, while it is waiting for time  seconds  to  elapse.   If
        this is the case, the command will be processed and the display will be
        updated immediately thereafter (reflecting any changes that the command
        may  have  specified).  This happens even if the command was incorrect.
        If a key is pressed while top is in the middle of updating the display,
        it  will finish the update and then process the command.  Some commands
        require additional information, and the user will be  prompted  accord‐
        ingly.   While  typing  this  information in, the user’s erase and kill
        keys (as set up by the command stty) are recognized, and a newline ter‐
        minates the input.
        These commands are currently recognized (^L refers to control-L):
        ^L     Redraw the screen.
        h or ? Display a summary of the commands (help screen).  Version infor‐
               mation is included in this display.
        q      Quit top.
        d      Change the number of displays to show (prompt for  new  number).
               Remember  that the next display counts as one, so typing d1 will
               make top show one final display and then immediately exit.
        n or # Change the number of processes to display (prompt for  new  num‐
        s      Change  the  number of seconds to delay between displays (prompt
               for new number).
        k      Send a signal ("kill" by default) to a list of processes.   This
               acts similarly to the command kill(1)).
        r      Change  the  priority (the "nice") of a list of processes.  This
               acts similarly to the command renice(8)).
        u      Display only processes owned by a specific username (prompt  for
               username).   If  the username specified is simply "+", then pro‐
               cesses belonging to all users will be displayed.
        o      Change the order in which the display is sorted.   This  command
               is  not  available on all systems.  The sort key names vary fron
               system to system but usually  include:   "cpu",  "res",  "size",
               "time".  The default is cpu.
        e      Display  a  list of system errors (if any) generated by the last
               kill or renice command.
        i      (or I) Toggle the display of idle processes.
        t      Toggle the display of the top process.
        The actual display varies depending on the  specific  variant  of  Unix
        that  the  machine  is running.  This description may not exactly match
        what is seen by top running on this  particular  machine.   Differences
        are listed at the end of this manual entry.
        The  top  few  lines  of the display show general information about the
        state of the system, including the last process id assigned to  a  pro‐
        cess  (on most systems), the three load averages, the current time, the
        number of existing processes, the number of  processes  in  each  state
        (sleeping,  running,  starting, zombies, and stopped), and a percentage
        of time spent in each of the processor states (user, nice, system,  and
        idle).   It also includes information about physical and virtual memory
        The remainder of the screen displays information about individual  pro‐
        cesses.   This  display  is  similar  in  spirit to ps(1) but it is not
        exactly the same.  PID is the process id, USERNAME is the name  of  the
        process’s  owner  (if -u is specified, a UID column will be substituted
        for USERNAME), PRI is the current priority of the process, NICE is  the
        nice  amount  (in  the  range -20 to 20), SIZE is the total size of the
        process (text, data, and stack), RES is the current amount of  resident
        memory (both SIZE and RES are given in kilobytes), STATE is the current
        state (one of "sleep", "WAIT", "run", "idl", "zomb", or  "stop"),  TIME
        is the number of system and user cpu seconds that the process has used,
        WCPU, when displayed, is the weighted cpu percentage (this is the  same
        value that ps(1) displays as CPU), CPU is the raw percentage and is the
        field that is sorted to determine the order of the processes, and  COM‐
        MAND  is  the name of the command that the process is currently running
        (if the process is swapped out, this column is marked "<swapped>").


        The "ABANDONED" state (known in the kernel as "SWAIT")  was  abandoned,
        thus the name.  A process should never end up in this state.


        William LeFebvre, EECS Department, Northwestern University


        TOP  user-configurable defaults for options.


        /dev/kmem      kernel memory
        /dev/mem       physical memory
        /etc/passwd         used to map uid numbers to user names
        /kernel        system image


        Don’t shoot me, but the default for -I has changed once again.  So many
        people were confused by the fact that top wasn’t showing them  all  the
        processes  that  I  have decided to make the default behavior show idle
        processes, just like it did in version 2.  But  to  appease  folks  who
        can’t  stand  that  behavior, I have added the ability to set "default"
        options in the environment variable  TOP  (see  the  OPTIONS  section).
        Those  who  want  the  behavior  that version 3.0 had need only set the
        environment variable TOP to "-I".
        The command name for swapped processes should be tracked down, but this
        would make the program run slower.
        As  with  ps(1),  things can change while top is collecting information
        for an update.  The picture it gives is only a close  approximation  to
        kill(1), ps(1), stty(1), mem(4), renice(8)
        Mem:  9220K  Active, 1032K Inact, 3284K Wired, 1MB Cache, 2M Buf, 1320K
        Free Swap:   91M Total, 79M Free, 13% Inuse, 80K In, 104 K Out
        K: Kilobyte
        M:     Megabyte
        %:     1/100
               number of pages active
        Inact: number of pages inactive
        Wired: number of pages wired down, including cached file data pages
        Cache: number of pages used for VM-level disk caching
        Buf:   number of pages used for BIO-level disk caching
        Free:  number of pages free
        Total: total available swap usage
        Free:  total free swap usage
        Inuse: swap usage
        In:    pages paged in from swap devices (last interval)
        Out:   pages paged out to swap devices (last interval)


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