htop(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | COMMAND-LINE OPTIONS | INTERACTIVE COMMANDS | COLUMNS | EXTERNAL LIBRARIES | CONFIG FILE | MEMORY SIZES | SEE ALSO | AUTHORS | COLOPHON

HTOP(1)                       User Commands                      HTOP(1)

NAME         top

       htop - interactive process viewer

SYNOPSIS         top

       htop [-dCFhpustvH]

DESCRIPTION         top

       htop is a cross-platform ncurses-based process viewer.

       It is similar to top, but allows you to scroll vertically and
       horizontally, and interact using a pointing device (mouse).  You
       can observe all processes running on the system, along with their
       command line arguments, as well as view them in a tree format,
       select multiple processes and act on them all at once.

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

COMMAND-LINE OPTIONS         top

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

       -d --delay=DELAY
              Delay between updates, in tenths of a second. If the delay
              value is less than 1, it is increased to 1, i.e. 1/10
              second. If the delay value is greater than 100, it is
              decreased to 100, i.e. 10 seconds.

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

       -F --filter=FILTER
              Filter processes by command

       -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).  This will force a list view unless you specify -t
              at the same time.

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

       -U --no-unicode
              Do not use unicode but ASCII characters for graph meters

       -M --no-mouse
              Disable support of mouse control

       --readonly
              Disable all system and process changing features

       -V --version
              Output version information and exit

       -t --tree
              Show processes in tree view. This can be used to force a
              tree view when requesting a sort order with -s.

       -H --highlight-changes=DELAY
              Highlight new and old processes

          --drop-capabilities[=off|basic|strict]
              Linux only; requires libcap support.
              Drop unneeded Linux capabilities.  In strict mode features
              like killing, changing process priorities, and reading
              process delay accounting information will not work, due to
              less capabilities held.

INTERACTIVE COMMANDS         top

       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
            process.

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

       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).

       Space
            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.

       w    Display the command line of the selected process in a
            separate screen, wrapped onto multiple lines as needed.

       x    Display the active file locks of the selected process in a
            separate screen.

       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.  Pressing Shift-F3 will
            cycle backwards.

            Alternatively the search can be started by simply typing the
            command you are looking for, although for the first
            character normal key bindings take precedence.

       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, <, >
            Selects a field for sorting, also accessible through < and
            >.  The current sort field is indicated by a highlight in
            the header.

       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
            Quit

       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.  Pressing "*" will expand or collapse all
            children of PIDs without parents, so typically PID 1 (init)
            and PID 2 (kthreadd on Linux, if kernel threads are shown).

       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.

       N    Sort by PID.

       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.)

       Z    Pause/resume process updates.

       m    Merge exe, comm and cmdline, where applicable. (This is a
            toggle key.)

       Ctrl-L
            Refresh: redraw screen and recalculate values.

       Numbers
            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.

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

            If the option 'Merge exe, comm and cmdline in Command'
            (toggled by the 'm' key) is active, the executable path
            (/proc/[pid]/exe) and the command name (/proc/[pid]/comm)
            are also shown merged with the command line, if available.

            The program basename is highlighted if set in the
            configuration. Additional highlighting can be configured for
            stale executables (cf. Exe column below).

       Comm The command name of the process obtained from
            /proc/[pid]/comm, if readable.

       Exe  The abbreviated basename of the executable of the process,
            obtained from /proc/[pid]/exe, if readable. htop is able to
            read this file on linux for ALL the processes only if it has
            the capability CAP_SYS_PTRACE or root privileges.

            The basename is marked in red if the executable used to run
            the process has been replaced or deleted on disk since the
            process started. This additional markup can be configured.

       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  The controlling terminal of the process.

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

       MINFLT
            The number of page faults happening in the main memory.

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

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

       CMAJFLT
            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.

       CUTIME (CUTIME+)
            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).

       CSTIME (CSTIME+)
            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).

       PRIORITY (PRI)
            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.

       STARTTIME (START)
            The time the process was started.

       PROCESSOR (CPU)
            The ID of the CPU the process last executed on.

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

       M_RESIDENT (RES)
            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
            instructions).

       M_LRS (LIB)
            The library size of the process.

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

       M_SWAP (SWAP)
            The size of the process's swapped pages.

       M_PSS (PSS)
            The proportional set size, same as M_RESIDENT but each page
            is divided by the number of processes sharing it.

       M_M_PSSWP (PSSWP)
            The proportional swap share of this mapping, unlike M_SWAP
            this does not take into account swapped out page of
            underlying shmem objects.

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

       PERCENT_CPU (CPU%)
            The percentage of the CPU time that the process is currently
            using.  This is the default way to represent CPU usage in
            Linux. Each process can consume up to 100% which means the
            full capacity of the core it is running on. This is
            sometimes called "Irix mode" e.g. in top(1).

       PERCENT_NORM_CPU (NCPU%)
            The percentage of the CPU time that the process is currently
            using normalized by CPU count. This is sometimes called
            "Solaris mode" e.g. in top(1).

       PERCENT_MEM (MEM%)
            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 Light-Weight Processes (=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.

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

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

       CNCLWB (IO_CANCEL)
            Bytes of cancelled write(2) I/O.

       IO_READ_RATE (DISK READ)
            The I/O rate of read(2) in bytes per second, for the
            process.

       IO_WRITE_RATE (DISK WRITE)
            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).

       CGROUP
            Which cgroup the process is in.

       OOM  OOM killer score.

       CTXT Incremental sum of voluntary and nonvoluntary context
            switches.

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

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

       PERCENT_IO_DELAY (IOD%)
            The percentage of time spent waiting for the completion of
            synchronous block I/O. Requires CAP_NET_ADMIN.

       PERCENT_SWAP_DELAY (SWAPD%)
            The percentage of time spent swapping in pages. Requires
            CAP_NET_ADMIN.

       COMM The command name for the process. Requires Linux kernel
            2.6.33 or newer.

       EXE  The executable file of the process as reported by the
            kernel. Requires CAP_SYS_PTRACE and PTRACE_MODE_READ_FSCRED.

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

EXTERNAL LIBRARIES         top

       While htop depends on most of the libraries it uses at build time
       there are two noteworthy exceptions to this rule. These
       exceptions both relate to data displayed in meters displayed in
       the header of htop and were intentionally created as optional
       runtime dependencies instead.  These exceptions are described
       below:

       libsystemd
              The bindings for libsystemd are used in the SystemD meter
              to determine the number of active services and the overall
              system state. Looking for the functions to determine these
              information at runtime allows for builds to support these
              meters without forcing the package manager to install
              these libraries on systems that otherwise don't use
              systemd.

              Summary: no build time dependency, optional runtime
              dependency on libsystemd via dynamic loading, with
              systemctl(1) fallback.

       libsensors
              The bindings for libsensors are used for the CPU
              temperature readings in the CPU usage meters if displaying
              the temperature is enabled through the setup screen. In
              order for htop to show these temperatures correctly
              though, a proper configuration of libsensors through its
              usual configuration files is assumed and that all CPU
              cores correspond to temperature sensors from the coretemp
              driver with core 0 corresponding to a sensor labelled
              "Core 0". The package temperature may be given as "Package
              id 0". If missing it is inferred as the maximum value from
              the available per-core readings.

              Summary: build time dependency on libsensors(3) C header
              files, optional runtime dependency on libsensors(3) via
              dynamic loading.

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 in a human-readable form.
       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) and limits.conf(5).

AUTHORS         top

       htop was originally developed by Hisham Muhammad.  Nowadays it is
       maintained by the community at <htop@groups.io>.

COLOPHON         top

       This page is part of the htop (an interactive process viewer)
       project.  Information about the project can be found at 
       ⟨http://hisham.hm/htop/⟩.  If you have a bug report for this
       manual page, see ⟨http://github.com/hishamhm/htop/issues⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/htop-dev/htop⟩ on 2021-06-20.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-06-18.)  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
       man-pages@man7.org

htop 3.1.0-dev                    2020                           HTOP(1)

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