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TLDR: htop (tldr-pages)

Display dynamic real-time information about running processes.

  • Start `htop`
    htop
  • Start `htop` displaying processes owned by a specific user
    htop {{-u|--user}} {{username}}
  • Display processes hierarchically in a tree view to show the parent-child relationships
    htop {{-t|--tree}}
  • Sort processes by a specified `sort_item` (use `htop --sort help` for available options)
    htop {{-s|--sort}} {{sort_item}}
  • Start `htop` with the specified delay between updates, in tenths of a second (i.e. 50 = 5 seconds)
    htop {{-d|--delay}} {{50}}
  • Disable all system and process changing features
    htop --readonly
  • See interactive commands while running `htop`
    {{<F1>|<?>}}
  • Switch to a different tab
    <Tab>
htop(1)
NAME SYNOPSIS DESCRIPTION COMMAND-LINE OPTIONS INTERACTIVE COMMANDS COLUMNS EXTERNAL LIBRARIES CONFIG FILE MEMORY SIZES SEE ALSO AUTHORS
HTOP(1)                                     User Commands                                    HTOP(1)



NAME
       htop - interactive process viewer

SYNOPSIS
       htop [-dCFhpustvH]

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

       It  is similar to top, but allows you to scroll vertically and horizontally, and interact us‐
       ing 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 acting on them all at once.

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

COMMAND-LINE OPTIONS
       Mandatory arguments to long options are mandatory for short options too.

       -d --delay=DELAY
              Delay between updates, in tenths of seconds. 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 de‐
              creased 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

       -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

INTERACTIVE COMMANDS
       The following commands are supported while in htop:

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

       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 pro‐
            cesses, 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 dis‐
            play the list of file descriptors opened by the process.

       w    Display the command line of the selected process in a separate screen, wrapped onto mul‐
            tiple 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  col‐
            umns are displayed, in which order.

       F3, /
            Incrementally search the command lines of all the displayed processes. The currently se‐
            lected (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  pro‐
            cesses.  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.

       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, "fol‐
            low" 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
       The following columns can display data about each process. A value of '-' in all the rows in‐
       dicates 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 set, and  if  read‐
            able,  the executable path (/proc/[pid]/exe) and the command name (/proc/[pid]/comm) are
            also shown merged with the command line.

       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 pro‐
            cesses only if it has the capability CAP_SYS_PTRACE or root privileges.

       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.

       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 chil‐
            dren 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 execut‐
            ing 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 in‐
            structions).

       M_DRS (DATA)
            The  data resident set size (data + stack) of the process (i.e. the size of anything ex‐
            cept 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 ac‐
            count 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.

       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 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.  Re‐
            quires 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
       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  in‐
       stead.  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 dy‐
              namic 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 la‐
              belled "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  de‐
              pendency on libsensors(3) via dynamic loading.

CONFIG FILE
       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 con‐
       figuration from /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  vari‐
       able (so you can have multiple configurations for different machines that share the same home
       directory, for example).

MEMORY SIZES
       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 mem‐
       ory size representations consistent throughout htop.

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

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



htop 3.0.5                                      2020                                         HTOP(1)

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