GRASS variables and environment variables

There are two types of variables:

shell environment variables,
GRASS gisenv variables.
There are a number of shell environment variable groups:
PNG driver
PS driver (PostScript)
variables for direct rendering
variables for internal use
Any setting which needs to be modifiable by a GRASS program (e.g. MONITOR) has to be a GRASS gisenv variable.

GRASS-related Files

GRASS maintains some settings in a number of files on the system. They are detailed below.

Setting environment variables


Setting environment variables depends on the shell being used:

  Bash:     export VARIABLE=value

or

  Csh:      setenv VARIABLE value

or

  Cmd.exe (Windows): set VARIABLE=value

Setting environment variables permanently

To get personal BASH shell definitions (aliases, color listing option, ...) into GRASS, store them in:
$HOME/.grass.bashrc
To get personal CSH shell definitions (aliases, color listing option, ...) into GRASS, store them in:
$HOME/.grass.cshrc

Setting GRASS variables

Use "g.gisenv" within GRASS. This permanently predefines GRASS variables in the .grassrc6 file.

Usage:

g.gisenv set="VARIABLE=VALUE"

It looks unusual with two equals signs, but g.gisenv serves dual duty for getting and setting GRASS variables.

If the user just specifies a variable name, it defaults to "get" mode. For example:

GRASS ~> g.gisenv GRASS_GUI
text


List of selected (GRASS related) environment variables

[ To be set from the terminal shell or startup scripts ]

GISBASE

  directory where GRASS lives. This is set automatically by the startup script.

GISRC

  name of .grassrc6 file. GISRCRC defines the system wide value while in a GRASS session.

GRASS_ADDON_PATH
[grass startup script]

  allows to specify additional paths to local GRASS modules extra to standard distribution.

GRASS_ADDON_ETC
[libgis, g.findetc]

  specify paths where support files (etc/) may be found external to standard distribution.

GRASS_BATCH_JOB

  defines the name (path) of a shell script to be processed as batch job.

GRASS_ERROR_MAIL

  set to any value to send user mail on an error or warning that  happens while stderr is being redirected.

GRASS_GNUPLOT
[i.spectral]

  program to use for plotting "gnuplot" data

GRASS_GUI

  either "text" or "tcltk" to define non-/graphical startup. Can also specify the name of the GUI to use, e.g. "gis.m", "d.m" or dqwxpython" (wx name subject to change). Also exists as a GRASS gisenv variable (see below). If this shell variable exists at GRASS startup, it will determine the GUI used. If it is not defined startup will default to the last GUI used.

GRASS_FONT_CAP
[g.mkfontcap, d.font, display drivers]

  Specifies an alternative location (to $GISBASE/etc/fontcap) for  the font configuration file.

GRASS_HEIGHT
[d.mon]

  defines the height of GRASS monitor, see also GRASS_WIDTH

GRASS_HTML_BROWSER
[init.sh, d.m, gis.m]

  defines name of HTML browser.  For most platforms this should be an executable in your PATH, or the full path to an executable.
Mac OS X runs applications differently from the CLI. Therefore, GRASS_HTML_BROWSER should be the application's signature, which is a domain-like name, just reversed. ie: com.apple.Safari. To find an application's signature, type the following in a Terminal (fill in the path to the application you are interested in, for example: /Applications/Safari.app):
grep -A 1 "CFBundleIdentifier" /path/to/application.app/Contents/Info.plist
The signature is the following the , without the bracketing tags.

GRASS_INT_ZLIB
[libgis]

  If the environment variable GRASS_INT_ZLIB exists, new compressed rasters will be compressed using zlib instead of RLE compression. Such rasters will have a "compressed" value of 2 in the cellhd file.
Obviously, decompression is controlled by the raster's "compressed" value, not the environment variable.

GRASS_MESSAGE_FORMAT
[various modules]
Maybe set to either "standard" or "gui" (normally GRASS takes care)

GRASS_MOUSE_BUTTON
[various modules]

  swaps mouse buttons for two-button or left-handed mice. Its value has three digits 1, 2, and 3, which represent default left, middle, and right buttons respectively. Setting to "132" will swap middle and right buttons. Note that this variable should be set before a display driver is initialized (e.g., d.mon x0).

GRASS_PAGER
[various modules]
Maybe set to either "less" or "more"

GRASS_PERL
[Used during install process for generating man pages]

  set perl with path

GRASS_RND_SEED

  set random seed for r.mapcalc rand() function

GRASS_SH
[shell scripts on Windows]
Path to bourne shell interpreter used to run shell scripts

GRASS_TCLSH
[nviz]

  set tclsh shell name to override 'tclsh'

GRASS_XTERM
lib/init/grass-xterm-wrapper
lib/init/grass-xterm-mac

  set to any value (e.g. rxvt, aterm, gnome-terminal, konsole) to substitute 'x-terminal-emulator' or 'xterm'. The Mac OS X app startup defaults to an internal '$GISBASE/etc/grass-xterm-mac', which emulates the necessary xterm functionality in Terminal.app.

GRASS_UI_TERM

  set to any value to use the terminal based parser

GRASS_VERSION

  reports the current version number (used by R-stats interface etc);

  should not be changed by user

GRASS_WIDTH
[d.mon]

  defines the width of GRASS monitor, see also GRASS_HEIGHT

GRASS_WISH
[d.m, nviz]

  set wish shell name to override 'wish'

GRASS_NO_GLX_PBUFFERS
[nviz]

  set to any value to disable the use of Pbuffers

GRASS_NO_GLX_PIXMAPS
[nviz]

  set to any value to disable the use of GLX Pixmaps

List of selected GRASS PNG driver environment variables

[ These variables control the function of the PNG Driver. ]

GRASS_PNGFILE

  name of PNG output file. If it ends with ".ppm" a PPM file will be created.

GRASS_WIDTH

  defines the width of GRASS monitor, see also GRASS_HEIGHT

GRASS_HEIGHT

  defines the height of GRASS monitor, see also GRASS_WIDTH

GRASS_BACKGROUNDCOLOR

  defines the background color of the image created by the PNG driver

GRASS_TRANSPARENT

  if "TRUE", the image created by the PNG driver will have a transparent background

GRASS_PNG_COMPRESSION

  compression level of PNG files (0 none, 1 fastest, 9 best)

GRASS_TRUECOLOR

  if "TRUE", the PNG driver generates a true-color image

GRASS_PNG_AUTO_WRITE

  tells the PNG driver to write the image to a file whenever a client disconnects, rather than waiting until you stop the monitor

GRASS_PNG_READ

  if "TRUE", the PNG driver will initialize the image from the contents of $GRASS_PNGFILE

GRASS_PNG_MAPPED

  if "TRUE", the PNG driver will map $GRASS_PNGFILE as its framebuffer, rather than using memory; this only works with BMP files

List of selected GRASS PS driver environment variables

[ These variables control the function of the PS Driver. ]

GRASS_PSFILE

  name of output file. If it ends with ".eps" an EPS file will be created.

GRASS_PAPER

  sets the screen dimensions and margins to fit a standard paper size, see also GRASS_WIDTH, GRASS_HEIGHT.

GRASS_WIDTH

  defines the width of the screen, see also GRASS_HEIGHT

GRASS_HEIGHT

  defines the height of the screen, see also GRASS_WIDTH

GRASS_TRUECOLOR

  if "TRUE", the PS driver generates color output, otherwise monochrome.

GRASS_LANDSCAPE

  if "TRUE", the screen is rotated 90 degrees counter-clockwise so that a "landscape" screen fits better on dqportrait" paper.

GRASS_PS_HEADER

  if "FALSE", the output is appended to any existing file, and no prolog or setup sections are generated.

GRASS_PS_TRAILER

  if "FALSE", no trailer section is generated.

List of selected GRASS environment variables for direct rendering

[ In addition to those which are understood by the PNG Driver, the following variables affect direct rendering. ]

GRASS_RENDER_IMMEDIATE

  tells the raster library to use its built-in PNG/PS driver rather than connecting to an external monitor process using sockets. If GRASS_RENDER_IMMEDIATE=TRUE is set, there is no need to run dqd.mon start=PNG"

GRASS_FONT

  specifies the font as either the name of a font from $GISBASE/etc/fontcap (or alternative fontcap file specifed by GRASS_FONT_CAP), or alternatively the full path to a FreeType font file.

GRASS_ENCODING

  the encoding to be assumed for text which is drawn using a freetype font; may be any encoding know to "iconv".

List of selected internal GRASS environment variables

[ These variables are intended for internal use only by the GRASS software to facilitate communiction between the GIS engine, GRASS scripts, and the GUI. The user should not set these in a GRASS session. They are meant to be set locally for specific commands. ]

GRASS_OVERWRITE
[all modules]

  toggles map overwrite.


 0 - maps are protected (default),

 1 - maps with identical names will be overwritten.
This variable is automatically created by g.parser so that the dq--overwrite" option will be inherited by dependant modules as the script runs. Setting either the GRASS_OVERWRITE environment variable or the OVERWRITE gisenv variable detailed below will cause maps with identical names to be overwritten.

GRASS_VERBOSE
[all modules]

  toggles verbosity level


 0 - only errors and warnings are printed

 1 - progress messages are printed (percent complete)

 2 - all module messages are printed

 3 - additional verbose messages are printed
This variable is automatically created by g.parser so that the "--verbose" or "--quiet" flags will be inherited by dependant modules as the script runs.

GRASS_REGION
[libgis]

  Override region settings, separate parameters with a ";". Format is the same as in the WIND region settings file. Otherwise use is the same as WIND_OVERRIDE.

WIND_OVERRIDE
[libgis]

   It causes programs to use the specified named region (created with e.g. "g.region save=...") to be used as the current region, instead of the region from the WIND file.
This allows programs such as gis.m to run external commands on an alternate region without having to modify the WIND file then change it back afterwards.

List of selected GRASS gisenv variables

[ Use g.gisenv to get/set/unset/change them ]

DEBUG
[entire GRASS]

  sets level of debug message output (0: no debug messages)
g.gisenv set=DEBUG=0

DM_FORM_MODE
[d.m]

  sets default form mode (txt or gui)
g.gisenv set=DM_FORM_MODE=txt

GISDBASE

  initial database

GIS_LOCK

  lock ID to prevent parallel GRASS use,

  process id of the start-up shell script

GRASS_DB_ENCODING
[d.what.vect/forms library]

  encoding of query form (utf-8, ascii, iso8859-1, koi8-r)

GRASS_GUI

  either "text" or "tcltk" to define non-/graphical startup. Can also specify the name of the GUI to use, e.g. "gis.m", "d.m" or dqwxpython" (wx name subject to change). Can also exist as a GRASS startup shell variable. The gisenv setting defines what GUI GRASS will use the next time it starts.

LOCATION

 full path to location directory

LOCATION_NAME

 initial location name

MAPSET

  initial mapset

OVERWRITE
[all modules]

  toggles map overwrite.

 With 0 maps are protected (default), 

 With 1 maps with identical names will be overwritten.

  Example: g.gisenv set="OVERWRITE=0"

  You can force an overwrite for an individual command by adding "--o" to the command: 

  r.in.gdal --o output=existing_map ...

GRASS-related Files

$HOME/.grassrc6

  stores the GRASS variables (but not environment variables)

$HOME/.grasslogin6

stores the DBMI passwords in this hidden file Only the file owner can access this file.

$HOME/GIS_ERROR_LOG

  If this file exists then all GRASS error and warning messages are  logged here. Applies to current user. To generate the file, use:

touch $HOME/GIS_ERROR_LOG

$GISBASE/GIS_ERROR_LOG

  If this file exists then all GRASS error and warning messages are  logged here. Applies to all users. (proper write permissions must be in place)

Note: Error and warning messages encountered while using the GUI menus are not logged.

SEE ALSO

g.gisenv, g.parser

Last changed: $Date: 2008-04-15 19:10:05 +0200 (Tue, 15 Apr 2008) $

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