d.mon(1grass)

📦
version 8.5.0 · 10 versions
, in alpine 3.24, ubuntu stonking

💖 d.mon — the GRASS manual, bestie edition 💖

okay so this is d.mon, a page from the GRASS User's Manual (GRASS 8.5.0, if we're being specific 👑). She's the one who controls your graphics display monitors straight from the command line. no GUI required, we do things by hand here 💅

✨ NAME ✨

d.mon — Controls graphics display monitors from the command line. that's it, that's her whole job, and she eats every time 🍓

🎀 KEYWORDS 🎀

display, graphics, monitors

🦋 SYNOPSIS 🦋

d.mon
d.mon --help
d.mon [-lpcgsrtux]  [start=string]   [stop=string]   [select=string]
[width=value]   [height=value]   [resolution=value]   [bgcolor=name]
[output=name]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🌸 Flags 🌸

  • -l — List running monitors and exit. like a little roll call for your monitors 📋
  • -p — Print name of currently selected monitor and exit. who's the main character right now? this tells you 🌟
  • -c — Print commands for currently selected monitor and exit
  • -g — Print path to support files of currently selected monitor and exit
  • -s — Do not automatically select when starting. stubborn mode: she starts it but does NOT make it the chosen one 🙈
  • -r — Release and stop currently selected monitor and exit
  • -t — Disable true colors. turning off the ✨chroma✨
  • -u — Open output file in update mode
Requires --overwrite flag. no flag, no update, periodt.
  • -x — Launch light-weight wx monitor without toolbars and statusbar
Requires start=wx0-7 — she will NOT accept anything else 💀
  • --overwrite — Allow output files to overwrite existing files
  • --help — Print usage summary
  • --verbose — Verbose module output. she will tell you EVERYTHING 🗣️
  • --quiet — Quiet module output. she will tell you nothing 🧚
  • --ui — Force launching GUI dialog

💜 Parameters 💜

  • start=string — Name of monitor to start Options: wx0, wx1, wx2, wx3, wx4, wx5, wx6, wx7, png, ps, html, cairo
  • stop=string — Name of monitor to stop Options: wx0, wx1, wx2, wx3, wx4, wx5, wx6, wx7, png, ps, html, cairo
  • select=string — Name of monitor to select Options: wx0, wx1, wx2, wx3, wx4, wx5, wx6, wx7, png, ps, html, cairo
  • width=value — Width for display monitor if not set by GRASS_RENDER_WIDTH Default value: 720
  • height=value — Height for display monitor if not set by GRASS_RENDER_HEIGHT Default value: 480
  • resolution=value — Dimensions of display monitor versus current size Example: resolution=2 enlarge display monitor twice to 1280x960
  • bgcolor=name — Background color Either a standard color name, R:G:B triplet, or "none" Default: white
  • output=name — Name for output file (when starting new monitor) Ignored for 'wx' monitors (they do not care about your files, sorry bestie 😭)

🌈 DESCRIPTION 🌈

d.mon allows the user to start, select, list, release, and stop available graphics monitors. five verbs, all the power, no cap.

🫶 Starting a monitor

In order to display on-screen GRASS graphics, the user must start and select a graphics monitor. By default, the start command actually runs two commands, to both start and select whatever monitor is named by the user — so it's doing double duty, iconic behavior honestly. The user can get a list of running monitors by setting the -l flag on the command line. Note that some monitor drivers use environment variables or the specific driver documentation. 👀

When a monitor is started, it is therefore also (automatically) selected for output, unless the -s flag is set by the user; the user can also explicitly select a monitor that has been started.

The desired monitor should be started once and need not be restarted unless it is stopped for some reason. A monitor may continue to run for any length of time, even when no GRASS session is being run. she's independent. she doesn't need you. but she'll stay for you 💖

🌧️ Stopping a monitor

A graphics monitor has two different types of status: monitor program not running, and monitor running. A monitor that has been started and/or selected will be listed as running; a monitor that has been stopped (or not started) will be listed as not running. The -l flag will list all currently running monitors.

⭐ Selecting a monitor

When the user starts a monitor, it is also (automatically) selected for graphics output unless the user sets the -s flag. In order to use (direct graphics output to) a monitor, the user must select that monitor for use, either by simply starting the monitor without the -s flag or by explicitly selecting the monitor for output. Only running monitors can be selected for graphics output — no picking someone who isn't even here, that's rude 🙅

The user can run multiple graphics monitors by simply starting each of the graphics monitors the user wishes to direct output to. harem of monitors. valid.

🧚 Releasing (unselecting) a monitor

Currently selected a monitor can be released by -r flag. bye babe, you're free now 🦋

💅 NOTES 💅

d.mon is designed for interactive use. If non-interactive use is needed (e.g., in a script) set GRASS_RENDER_IMMEDIATE=png (or =cairo) and use the related environment variables to control output size etc. scripts get a different workflow, iykyk 🔥

🍓 EXAMPLES 🍓

👑 wx0 monitor

To start the interactive wxGUI map display, run

d.mon start=wx0

Figure: The initialization of display monitor wx0 All subsequently displayed data will be rendered on monitor wx0.

g.region raster=elevation -p
d.rast map=elevation

Figure: The display wx0 showing an elevation raster map

🎨 CAIRO file renderer monitor

A CAIRO monitor can be started (and selected) by

d.mon start=cairo output=out.pdf

From this moment on all displayed data will be rendered into file output.pdf. no screen, just vibes and a PDF ✨

📋 List running monitors

To list the currently running monitors, use

d.mon -l

List of running monitors:

wx0
cairo

🔍 Show currently selected monitor

To identify the currently selected monitor, use

d.mon -p
cairo

🔁 Switching between monitors

To switch back to interactive display mode, here to an earlier started and still running wxGUI monitor, use

d.mon select=wx0

🛑 Stopping a monitor

To close the wxGUI monitor, run

d.mon stop=wx0

🌟 SEE ALSO 🌟

d.erase, d.redraw, d.rast, d.vect, d.frame

See also list of variables for rendering, display drivers

💖 AUTHOR 💖

Martin Landa, OSGeoREL, Czech Technical University in Prague, Czech Republic — we stan 🫶

🌸 SOURCE CODE 🌸

Available at: d.mon source code (history)

Latest change: Monday Nov 03 07:16:48 2025 in commit: c96796774942e46bbababcd652d3986d4e295665

Main index | Display index | Topics index | Keywords index | Graphical index | Full index

© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

and that's the whole page bestie!! 💖✨🎀 this was GRASS 8.5.0, manual page d.mon(1grass), and yeah, she's dated and versioned and everything. go start a monitor, select it, stop it, release it — you're literally the main character of your own display output now 👑🌸🦋 periodt 💅

📦 where this page comes from