htop(1) — Linux manual page


HTOP(1)                           Utils                          HTOP(1)

NAME         top

       htop - interactive process viewer

SYNOPSIS         top

       htop [-dChustv]

DESCRIPTION         top

       Htop is a free (GPL) ncurses-based process viewer for Linux.

       It is similar to top, but allows you to scroll vertically and
       horizontally, so you can see all the processes running on the
       system, along with their full command lines, as well as viewing
       them as a process tree, selecting multiple processes and acting
       on them all at once.

       Tasks related to processes (killing, renicing) can be done
       without entering their PIDs.


       Mandatory arguments to long options are mandatory for short
       options too.

       -d --delay=DELAY
              Delay between updates, in tenths of seconds

       -C --no-color --no-colour
              Start htop in monochrome mode

       -h --help
              Display a help message and exit

       -p --pid=PID,PID...
              Show only the given PIDs

       -s --sort-key COLUMN
              Sort by this column (use --sort-key help for a column

       -u --user=USERNAME
              Show only the processes of a given user

       -v --version
              Output version information and exit

       -t --tree
              Show processes in tree view


       The following commands are supported while in htop:

       Up, Alt-k
            Select (highlight) the previous process in the process list.
            Scroll the list if necessary.

       Down, Alt-j
            Select (highlight) the next process in the process list.
            Scroll the list if necessary.

       Left, Alt-h
            Scroll the process list left.

       Right, Alt-l
            Scroll the process list right.

       PgUp, PgDn
            Scroll the process list up or down one window.

       Home Scroll to the top of the process list and select the first

       End  Scroll to the bottom of the process list and select the last

       Ctrl-A, ^
            Scroll left to the beginning of the process entry (i.e.
            beginning of line).

       Ctrl-E, $
            Scroll right to the end of the process entry (i.e. end of

            Tag or untag a process. Commands that can operate on
            multiple processes, like "kill", will then apply over the
            list of tagged processes, instead of the currently
            highlighted one.

       c    Tag the current process and its children. Commands that can
            operate on multiple processes, like "kill", will then apply
            over the list of tagged processes, instead of the currently
            highlighted one.

       U    Untag all processes (remove all tags added with the Space or
            c keys).

       s    Trace process system calls: if strace(1) is installed,
            pressing this key will attach it to the currently selected
            process, presenting a live update of system calls issued by
            the process.

       l    Display open files for a process: if lsof(1) is installed,
            pressing this key will display the list of file descriptors
            opened by the process.

       F1, h, ?
            Go to the help screen

       F2, S
            Go to the setup screen, where you can configure the meters
            displayed at the top of the screen, set various display
            options, choose among color schemes, and select which
            columns are displayed, in which order.

       F3, /
            Incrementally search the command lines of all the displayed
            processes. The currently selected (highlighted) command will
            update as you type. While in search mode, pressing F3 will
            cycle through matching occurrences.

       F4, \
            Incremental process filtering: type in part of a process
            command line and only processes whose names match will be
            shown. To cancel filtering, enter the Filter option again
            and press Esc.

       F5, t
            Tree view: organize processes by parenthood, and layout the
            relations between them as a tree. Toggling the key will
            switch between tree and your previously selected sort view.
            Selecting a sort view will exit tree view.

       F6   On sorted view, select a field for sorting, also accessible
            through < and >.  The current sort field is indicated by a
            highlight in the header.  On tree view, expand or collapse
            the current subtree. A "+" indicator in the tree node
            indicates that it is collapsed.

       F7, ]
            Increase the selected process's priority (subtract from
            'nice' value).  This can only be done by the superuser.

       F8, [
            Decrease the selected process's priority (add to 'nice'

       F9, k
            "Kill" process: sends a signal which is selected in a menu,
            to one or a group of processes. If processes were tagged,
            sends the signal to all tagged processes.  If none is
            tagged, sends to the currently selected process.

       F10, q

       I    Invert the sort order: if sort order is increasing, switch
            to decreasing, and vice-versa.

       +, - When in tree view mode, expand or collapse subtree. When a
            subtree is collapsed a "+" sign shows to the left of the
            process name.

       a (on multiprocessor machines)
            Set CPU affinity: mark which CPUs a process is allowed to

       u    Show only processes owned by a specified user.

       M    Sort by memory usage (top compatibility key).

       P    Sort by processor usage (top compatibility key).

       T    Sort by time (top compatibility key).

       F    "Follow" process: if the sort order causes the currently
            selected process to move in the list, make the selection bar
            follow it. This is useful for monitoring a process: this
            way, you can keep a process always visible on screen. When a
            movement key is used, "follow" loses effect.

       K    Hide kernel threads: prevent the threads belonging the
            kernel to be displayed in the process list. (This is a
            toggle key.)

       H    Hide user threads: on systems that represent them
            differently than ordinary processes (such as recent NPTL-
            based systems), this can hide threads from userspace
            processes in the process list. (This is a toggle key.)

       p    Show full paths to running programs, where applicable. (This
            is a toggle key.)

            Refresh: redraw screen and recalculate values.

            PID search: type in process ID and the selection highlight
            will be moved to it.

COLUMNS         top

       The following columns can display data about each process. A
       value of '-' in all the rows indicates that a column is
       unsupported on your system, or currently unimplemented in htop.
       The names below are the ones used in the "Available Columns"
       section of the setup screen. If a different name is shown in
       htop's main screen, it is shown below in parenthesis.

            The full command line of the process (i.e. program name and

       PID  The process ID.

       STATE (S)
            The state of the process:
               S for sleeping (idle)
               R for running
               D for disk sleep (uninterruptible)
               Z for zombie (waiting for parent to read its exit status)
               T for traced or suspended (e.g by SIGTSTP)
               W for paging

       PPID The parent process ID.

       PGRP The process's group ID.

       SESSION (SID)
            The process's session ID.

       TTY_NR (TTY)
            The controlling terminal of the process.

            The process ID of the foreground process group of the
            controlling terminal.

            The number of page faults happening in the main memory.

            The number of minor faults for the process's waited-for
            children (see MINFLT above).

            The number of page faults happening out of the main memory.

            The number of major faults for the process's waited-for
            children (see MAJFLT above).

       UTIME (UTIME+)
            The user CPU time, which is the amount of time the process
            has spent executing on the CPU in user mode (i.e. everything
            but system calls), measured in clock ticks.

       STIME (STIME+)
            The system CPU time, which is the amount of time the kernel
            has spent executing system calls on behalf of the process,
            measured in clock ticks.

            The children's user CPU time, which is the amount of time
            the process's waited-for children have spent executing in
            user mode (see UTIME above).

            The children's system CPU time, which is the amount of time
            the kernel has spent executing system calls on behalf of all
            the process's waited-for children (see STIME above).

            The kernel's internal priority for the process, usually just
            its nice value plus twenty. Different for real-time

       NICE (NI)
            The nice value of a process, from 19 (low priority) to -20
            (high priority). A high value means the process is being
            nice, letting others have a higher relative priority. The
            usual OS permission restrictions for adjusting priority

            The time the process was started.

            The ID of the CPU the process last executed on.

       M_SIZE (VIRT)
            The size of the virtual memory of the process.

            The resident set size (text + data + stack) of the process
            (i.e. the size of the process's used physical memory).

       M_SHARE (SHR)
            The size of the process's shared pages.

       M_TRS (CODE)
            The text resident set size of the process (i.e. the size of
            the process's executable instructions).

       M_DRS (DATA)
            The data resident set size (data + stack) of the process
            (i.e. the size of anything except the process's executable

       M_LRS (LIB)
            The library size of the process.

       M_DT (DIRTY)
            The size of the dirty pages of the process.

       ST_UID (UID)
            The user ID of the process owner.

            The percentage of the CPU time that the process is currently

            The percentage of memory the process is currently using
            (based on the process's resident memory size, see M_RESIDENT

       USER The username of the process owner, or the user ID if the
            name can't be determined.

       TIME (TIME+)
            The time, measured in clock ticks that the process has spent
            in user and system time (see UTIME, STIME above).

       NLWP The number of threads in the process.

       TGID The thread group ID.

       CTID OpenVZ container ID, a.k.a virtual environment ID.

       VPID OpenVZ process ID.

       VXID VServer process ID.

       RCHAR (RD_CHAR)
            The number of bytes the process has read.

       WCHAR (WR_CHAR)
            The number of bytes the process has written.

       SYSCR (RD_SYSC)
            The number of read(2) syscalls for the process.

       SYSCW (WR_SYSC)
            The number of write(2) syscalls for the process.

            Bytes of read(2) I/O for the process.

            Bytes of write(2) I/O for the process.

            Bytes of cancelled write(2) I/O.

            The I/O rate of read(2) in bytes per second, for the

            The I/O rate of write(2) in bytes per second, for the

       IO_RATE (DISK R/W)
            The I/O rate, IO_READ_RATE + IO_WRITE_RATE (see above).

            Which cgroup the process is in.

       OOM  OOM killer score.

            The I/O scheduling class followed by the priority if the
            class supports it:
               R for Realtime
               B for Best-effort
               id for Idle

            The percentage of time spent waiting for a CPU (while
            runnable). Requires CAP_NET_ADMIN.

            The percentage of time spent waiting for the completion of
            synchronous block I/O. Requires CAP_NET_ADMIN.

            The percentage of time spent swapping in pages. Requires

       All other flags
            Currently unsupported (always displays '-').

CONFIG FILE         top

       By default htop reads its configuration from the XDG-compliant
       path ~/.config/htop/htoprc -- the configuration file is
       overwritten by htop's in-program Setup configuration, so it
       should not be hand-edited. If no user configuration exists htop
       tries to read the system-wide configuration from
       ${prefix}/etc/htoprc and as a last resort, falls back to its hard
       coded defaults.

       You may override the location of the configuration file using the
       $HTOPRC environment variable (so you can have multiple
       configurations for different machines that share the same home
       directory, for example).

MEMORY SIZES         top

       Memory sizes in htop are displayed as they are in tools from the
       GNU Coreutils (when ran with the --human-readable option). This
       means that sizes are printed in powers of 1024. (e.g., 1023M =
       1072693248 Bytes)

       The decision to use this convention was made in order to conserve
       screen space and make memory size representations consistent
       throughout htop.

SEE ALSO         top

       proc(5), top(1), free(1), ps(1), uptime(1), limits.conf(5)

AUTHORS         top

       htop is developed by Hisham Muhammad <>.

       This man page was written by Bartosz Fenski <> for the
       Debian GNU/Linux distribution (but it may be used by others). It
       was updated by Hisham Muhammad, and later by Vincent Launchbury,
       who wrote the 'Columns' section.

COLOPHON         top

       This page is part of the htop (an interactive process viewer)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this
       manual page, see ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2021-04-01.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2020-09-07.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

htop 2.2.0                        2015                           HTOP(1)

Pages that refer to this page: proc(5)iotop(8)