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

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


       Mandatory arguments to long options are mandatory for short options

       -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 list)

       -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 line).

            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

       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' value)

       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

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

       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

            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 processes.

       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 apply.

            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 above).

       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 process.

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

       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

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

       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 2020-06-09.  (At that time, the
       date of the most recent commit that was found in the repository was
       2019-03-06.)  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)procfs(5)iotop(8)