Provided by: kmscon_9.0.0-5build2_amd64 
NAME
kmscon - KMS/DRM based System Console
SYNOPSIS
kmscon [OPTIONS...]
kmscon -l [OPTIONS...] -- /bin/login [/bin/login-OPTIONS...]
DESCRIPTION
kmscon is a KMS/DRM-based system console with an integrated terminal emulator for linux
operating systems. It was designed as a replacement for the linux kernel console and
virtual terminals.
When run in default mode, kmscon allocates a virtual terminal and provides a terminal
emulator on it. It can thus be used as replacement for the linux console and agetty(1) on
virtual terminals. Compared to the linux console, kmscon provides a rich set of enhanced
features including full internationalized keyboard support, full UTF-8 input/font support,
hardware-accelerated rendering, multi-seat support and more.
When run in listener mode, kmscon watches the system for new seats and automatically
provides a system console on it.
OPTIONS
Boolean options take no arguments. If the default value is true, then you can disable the
option by prefixing it with no-.
General Options:
-h, --help
Prints a short help text and exits. (default: off)
-v, --verbose
Be more verbose. (default: off)
--debug
Print debug messages. Works only if kmscon was compiled with debug mode enabled.
(default: off)
--silent
Suppress notices and warnings. (default: off)
--configdir {/path/to/config/dir/}
Specify path to config directory. (default: /etc/kmscon)
--listen
Run kmscon in listen-mode. See section below for more information. (default: off)
Seat Options:
--vt {/path/to/vt}
Use this VT. If not specified, kmscon tries to find a VT by itself. On seats without
VTs, kmscon simply activates itself automatically without using any VT. Please note
that you cannot use this option if kmscon runs on multiple seats (see --seats). To
avoid this, specify this option in a seat configuration
/etc/kmscon/{seat}.kmscon.conf.
You must not run multiple applications on a single VT, otherwise, you might get an
unresponsive system. Also note, by default, kmscon tries to use it's controlling
terminal as VT and if that fails, it tries to allocate a new unused VT.
--switchvt
If kmscon is started on a VT that is currently not active, this option makes kmscon
activate this VT during startup. The same way, during shutdown kmscon will reactivate
the VT that was previously active. (default: on)
--seats {list,of,seats}
List of seats kmscon will run on. Use 'all' to make kmscon run on all seats. Use
'all,' to make kmscon run on a seat called 'all' (empty entries are ignored). Use
'current' to make kmscon run on the current seat. (default: "current")
If kmscon runs on multiple seats, all seats are independent of each other. You can
either run a different kmscon process on each seat or make a single kmscon process run
on multiple seats. In the latter case, global state can be shared to reduce memory
consumption (like glyph-caches).
Session Options:
--session-max {num}
Change the maximum number of sessions that are allowed on each seat. Use '0' for no
limit. (default: 50)
--session-control
Allow keyboard-shortcuts to control the session manager. This allows the use to create
new sessions, kill sessions and switch sessions via keyboard input. (default: off)
--terminal-session
Start a terminal session after setup is done. (default: on)
Terminal Options:
-l, --login
Specify the application that is started on new terminal sessions. This takes no
argument but instead everything left after all options have been parsed is used as
argument to this option. Note that nothing after two dashes -- is parsed as regular
option by kmscon. (default: /bin/login -p)
This example starts '/bin/bash -i' on each new terminal session: ./kmscon --login
--debug --no-switchvt -- /bin/bash -i
-t {term}, --term {term}
This changes the $TERM environment variable that is set on new terminal sessions.
(default: xterm-256color)
--reset-env
Reset environment before spawning the child process. (default: on)
--sb-size {size}
Maximum scrollback-buffer line count. (default: 1000)
Input Options:
--xkb-model {model}
Keyboard model. This should normally not be changed. (default: {xkb default})
--xkb-layout {layout}
Keyboard layout. (default: {xkb default})
German keyboard example: --xkb-layout=de
--xkb-variant {variant}
Keyboard variant. (default: {xkb default})
--xkb-options {options}
Keyboard options. (default: {xkb default})
--xkb-keymap {file}
Path to a single predefined keymap file. This takes precedence over the above options.
An empty path "" is interpreted as not using a keymap. (default: not used)
--xkb-compose-file {file}
Path to a single predefined compose file. An empty path "" is interpreted as using the
default compose file. The default compose file search order is described in
Compose(5). The locale is determined from the first of LC_ALL, LC_CTYPE, or LANG
that's set to a non-empty value. If the locale cannot be determined, C is assumed. If
no compose file is found, composing is disabled. (default: search the compose file
corresponding to the current locale)
--xkb-repeat-delay {delay}
Delay after key was pressed until key-repeat starts (in milliseconds). (default: 250)
--xkb-repeat-rate {rate}
Time between two key-repeats (in milliseconds). (default: 50)
Grabs / Keyboard-Shortcuts:
All keyboard shortcuts (here: grabs) in kmscon can be modified with these options. The
argument to such an option is a list of comma-separated keyboard-shortcuts that should
trigger the specified action. To disable a shortcut, pass an empty argument (empty list).
A keyboard shortcut exists of a list of modifiers followed by a single key. All modifiers
must be down when the key is pressed for the shortcut to be detected. A modifier is
surrounded by '<' and '>' (like '<shift>'). A key is the name of a keysym (like 'a' or
'Return'). Keysyms are case-sensitive and kmscon will suggest a keysym name if you entered
a wrong case. However, kmscon can not always guess the right case as lower-case-only
keysyms are ambiguous.
If a key generates multiple keysyms in your keyboard layout, you can match these keys by
concatenating the keysyms with a '+' (like 'H+E+L+L+O'). This does not mean that all the
listed keys must be pressed! It's rather a way to match multi-keysym keys.
Valid modifiers are: Shift, Control/Ctrl, Alt, Logo (Windows/Apple key)
--grab-scroll-up {grab}
Scroll up in scrollback buffer by one line. (default: <Shift>Up)
--grab-scroll-down {grab}
Scroll down in scrollback buffer by one line. (default: <Shift>Down)
--grab-page-up {grab}
Scroll up in scrollback buffer by one page. (default: <Shift>Prior/PageUp)
--grab-page-down {grab}
Scroll down in scrollback buffer by one page. (default: <Shift>Next/PageDown)
--grab-zoom-in {grab}
Increase font size of the current terminal. (default: <Ctrl>Plus)
--grab-zoom-out {grab}
Decrease font size of the current terminal. (default: <Ctrl>Minus)
--grab-session-next {grab}
Switch to next session. (default: <Ctrl><Logo>Right)
--grab-session-prev {grab}
Switch to previous session. (default: <Ctrl><Logo>Left)
--grab-session-dummy {grab}
Switch to dummy session (black screen). (default: <Ctrl><Logo>Escape)
--grab-session-close {grab}
Close current session (press twice to kill it). (default: <Ctrl><Logo>BackSpace)
--grab-terminal-new {grab}
Create new terminal session next to current session. (default: <Ctrl><Logo>Return)
Video Options:
--drm
Use DRM devices as display devices, too. fbdev devices are always used, but DRM
devices are only used if this option is on. (default: on)
--hwaccel
Use 3D hardware acceleration. Note that this should be used in conjunction with --drm.
On newer hardware, this can speed up rendering by multiple orders of magnitude.
However, on older hardware this might even slow down rendering speed. (default: off)
--gpus {all,aux,primary}
GPU selection algorithm. If 'all' then all found GPUs are used. If 'aux' then primary
and auxiliary GPUs are used. If 'primary' then only primary GPUs are used. Primary
GPUs are the default GPU on a seat. There is always only one primary GPU on a seat.
Auxiliary GPUs are hotpluggable GPUs that provide additional independent displays.
(default: all)
--render-engine {engine}
Select console render engine. Available engines are 'bblit', 'bbulk' and 'gltex'.
(default: detect by GPU type)
--render-timing
Display timing information of the render engines. This should only be used to debug
render engines. (default: off)
Font Options:
--font-engine {engine}
Select font-engine. Available engines are 'pango', 'unifont' and '8x16'. (default:
pango)
--font-size {points}
Font size in points. (default: 12)
--font-name {name}
Font name. (default: monospace)
--font-dpi {dpi}
DPI used for font-rendering. Per monitor DPI values overwrite this global default.
(default: 96)
Palette Options:
--palette {name}
Change the default color palette. Setting this to custom takes the color palette from
the following options.
In the following options color is an RGB color value written as three comma-separated
integers between 0 and 255 inclusive.
--palette-black {color}
Change the black color in the custom palette to color. (default: 0, 0, 0)
--palette-red {color}
Change the red color in the custom palette to color. (default: 205, 0, 0)
--palette-green {color}
Change the green color in the custom palette to color. (default: 0, 205, 0)
--palette-yellow {color}
Change the yellow color in the custom palette to color. (default: 205, 205, 0)
--palette-blue {color}
Change the blue color in the custom palette to color. (default: 0, 0, 238)
--palette-magenta {color}
Change the magenta color in the custom palette to color. (default: 205, 0, 205)
--palette-cyan {color}
Change the cyan color in the custom palette to color. (default: 0, 205, 205)
--palette-light-grey {color}
Change the light grey color in the custom palette to color. (default: 229, 229,229)
--palette-dark-grey {color}
Change the dark grey color in the custom palette to color. (default: 127, 127, 127)
--palette-light-red {color}
Change the light red color in the custom palette to color. (default: 255, 0, 0)
--palette-light-green {color}
Change the light green color in the custom palette to color. (default: 0, 255, 0)
--palette-light-yellow {color}
Change the light yellow color in the custom palette to color. (default: 255, 255, 0)
--palette-light-blue {color}
Change the light blue color in the custom palette to color. (default: 92, 92, 255)
--palette-light-magenta {color}
Change the light magenta color in the custom palette to color. (default: 255, 0, 255)
--palette-light-cyan {color}
Change the light cyan color in the custom palette to color. (default: 0, 255, 255)
--palette-white {color}
Change the white color in the custom palette to color. (default: 255, 255, 255)
--palette-foreground {color}
Change the default foreground color in the custom palette to color. (default: 229,
229, 229)
--palette-background {color}
Change the default background color in the custom palette to color. (default: 0, 0, 0)
CONFIGURATION
Default configuration directory is /etc/kmscon and the main configuration file is called
/etc/kmscon/kmscon.conf. You can provide an additional configuration file for each seat
via /etc/kmscon/{seatname}.kmscon.conf. Any command-line option that can be passed to
kmscon can also be put into those configuration files. For example:
font-name=Meslo LG M
font-size=14
login=/bin/bash -i
palette-foreground=255, 0, 0
Command-line options overwrite configuration file options. And per-seat configuration
files overwrite the global configuration file.
DEFAULT MODE
In default mode, kmscon acts as a replacement for agetty(1). kmscon opens a virtual
terminal and provides a system console on it. It replaces the linux-console on this VT.
You can select the virtual terminal via the --vt option. kmscon will seamlessly integrate
into existing setups so you can use X, Wayland or any other Graphics Systems
simultaneously. You can even use the linux-console on all the other virtual terminals.
By default, kmscon runs on seat0 but you can change the seat via the --seats option. For
seats without virtual terminals, kmscon will automatically activate itself and run
exclusively on that seat. If the virtual terminal or the seat that kmscon runs on is gone,
kmscon will automatically exit. See the Listener-Mode to avoid this.
kmscon spawns login(1) on each new terminal. After a session exits, kmscon automatically
respawns the next session. You can change the program that is spawned with the --login
option. To stop kmscon, send SIGTERM to the kmscon process.
Keyboard input is done by libxkbcommon. This provides the same features as the X11
Keyboard System but without any dependencies on X11 libraries. See the --xkb-{option}
options for ways to change the keyboard layout, model, repeat rates and more. For instance
--xkb-layout=de changes the keyboard layout to German.
kmscon uses KMS/DRM to access graphics devices (like the X-Server does). Compared to the
linux console this allows kmscon to provide much better font-rendering and enhanced
monitor control. However, for backwards compatibility, kmscon can also use fbdev devices.
Hotpluggable graphics devices are marked as auxiliary devices, primary GPUs on a seat are
marked as primary. Other GPUs stay unmarked. By default kmscon uses all graphics devices
but you can make it use only primary or auxiliary devices with the --gpus option.
LISTENER MODE
If started in listen-mode (--listen) kmscon will run as system daemon and provide a system
console on each seat that shows up if that seat does not have virtual terminals. On seats
with virtual terminals you should run kmscon in default mode.
Several options are exclusively limited to listen-mode, other than these, kmscon behaves
the same way as in default-mode.
SESSIONS
If kmscon is active on a seat, the internal session-manager is woken up. At most times,
only the terminal-session is active, but kmscon can also support any other session type.
You can switch between sessions with keyboard-shortcuts and you can create/destroy
sessions during runtime.
Dummy sessions simply show a black screen and are used if no other session is available.
Otherwise, dummy sessions are hidden from the user so they cannot switch to it.
Terminal sessions provide a terminal emulator. They are the main session type and provide
all the terminal-emulation functionality.
VIRTUAL TERMINALS
Historically, linux provides virtual terminals (VT) only on seat seat0. This is because
only one VT can be active at a time but in multi-seat environments you want multiple
active VTs, one per seat. It is easy to run kmscon on seat0 on a VT, however, if you want
to run kmscon on another seat, there are no VTs. This means, you can only run one
application that uses graphics devices on these seats. In most environments this is the
X-Server. But if you want to run kmscon together with the X-Server (or any other graphics
server), you need a mechanism to notify these servers when they are active. This is done
via VT APIs on seat0. But note that if the kernel is compiled without CONFIG_VT (which
controls whether VTs are available), then even seat0 does not have VTs.
SEE ALSO
console(4), Compose(5)