NAME¶
htop - interactive process viewer
SYNOPSIS¶
htop [-dChusv]
DESCRIPTION¶
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.
Tasks related to processes (killing, renicing) can be done without entering
their PIDs.
COMMAND-LINE OPTIONS¶
Mandatory arguments to long options are madatory 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
- -u --user=USERNAME
- Show only the processes of a given user
- -s --sort-key COLUMN
- Sort by this column (use --sort-key help for a column
list)
- -v --version
- Output version information and exit
INTERACTIVE COMMANDS¶
The following commands are supported while in htop:
- Arrows, PgUP, PgDn, Home, End
- Scroll the process list.
- 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.
- U
- Untag all processes (remove all tags added with the Space
key).
- 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.
- L
- Trace process library calls: if ltrace(1) is installed,
pressing this key will attach it to the currently selected process,
presenting a live update of library calls issued 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, <, >
- Select a field for sorting. 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.
- 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.)
- 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 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).
- PID
- The process ID.
- PPID
- The parent process ID.
- PGRP
- The process's group ID.
- SESSION (SESN)
- 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.
- 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 it's exit status)
T for traced or suspended (e.g by SIGTSTP)
W for paging
- PROCESSOR (CPU)
- The ID of the CPU the process last executed on.
- NLWP
- The number of threads in the process.
- 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. Only root can lower the
value.
- PERCENT_CPU (CPU%)
- The percentage of the CPU time that the process is
currently using.
- 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.
- TIME (TIME+)
- The time, measured in clock ticks that the process has
spent in user and system time (see UTIME, STIME above).
- 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
- 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 kernels internal priority for the process, usually just
it's nice value plus twenty. Different for real-time processes.
- PERCENT_MEM
- The percentage of memory the process is currently using
(based on the process's resident memory size, see M_RESIDENT below).
- M_SIZE (VIRT)
- Size in memory of the total program size.
- M_RESIDENT (RES)
- The resident set size, i.e the size of the text and data
sections, plus stack usage.
- M_SHARE (SHR)
- The size of the process's shared pages
- M_TRS (CODE)
- The size of the text segment of the process (i.e the size
of the processes executable instructions).
- M_LRS (LIB)
- The library size of the process.
- M_DRS (DATA)
- The size of the data segment plus stack usage 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.
- USER
- The username of the process owner, or the user ID if the
name can't be determined.
- STARTTIME
- The time the process was started.
- 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.
- IO_READ_RATE (IORR)
- The I/O rate of read(2) in bytes per second, for the
process.
- IO_WRITE_RATE (IOWR)
- The I/O rate of write(2) in bytes per second, for the
process.
- IO_RATE (IO)
- The I/O rate, IO_READ_RATE + IO_WRITE_RATE (see
above).
- CNCLWB (IO_CANCEL)
- Bytes of cancelled write(2) I/O.
- CGROUP
- Which cgroup the process is in.
- CTID
- OpenVZ container ID, a.k.a virtual environment ID.
- VPID
- OpenVZ process ID.
- VXID
- VServer process ID.
- All other flags
- Currently unsupported (always displays '-').
SEE ALSO¶
proc(5),
top(1),
free(1),
ps(1),
uptime(1)
AUTHORS¶
htop is developed by Hisham Muhammad <loderunner@users.sourceforge.net>.
This man page was written by Bartosz Fenski <fenio@o2.pl> 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.