Provided by: grass-doc_8.4.1-1_all 
NAME
g.gisenv - Outputs and modifies the user’s current GRASS variable settings.
Prints all defined GRASS variables if no option is given.
KEYWORDS
general, settings, variables, scripts
SYNOPSIS
g.gisenv
g.gisenv --help
g.gisenv [-sn] [get=variable[,variable,...]] [set="variable=value"] [unset=variable[,variable,...]]
[store=string] [separator=character] [--help] [--verbose] [--quiet] [--ui]
Flags:
-s
Use shell syntax (for "eval")
-n
Do not use shell syntax
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
get=variable[,variable,...]
GRASS variable to get
set="variable=value"
GRASS variable to set
unset=variable[,variable,...]
GRASS variable to unset
store=string
Where GRASS variable is stored
Options: gisrc, mapset
Default: gisrc
separator=character
Separator for multiple GRASS variables
Special characters: pipe, comma, space, tab, newline
Default: newline
DESCRIPTION
g.gisenv outputs and modifies the user’s current GRASS GIS variable settings. When a user runs GRASS,
certain variables are set specifying the GRASS data base, project, mapset, peripheral device drivers,
etc., being used in the current GRASS session. These variable name settings are recognized as long as the
user is running a GRASS session.
OPTIONS
No prompts are given to the user when running g.gisenv.
If run without arguments, g.gisenv lists all of the user’s current GRASS variable settings. Results are
sent to standard output, and may look like this:
GISDBASE=/opt/grassdata/
LOCATION_NAME=nc_spm_08_grass7
MAPSET=/user1
GUI=gui
If the user specifies a get=variable_name on the command line
g.gisenv MAPSET
only the value for that particular GRASS variable is output to standard output. Possible variable names
depend on the user’s system, see variables list for details. Note that the variable names are
case-insensitive.
While other variables may be associated with each GRASS session (e.g., GRASS_GUI, GIS_LOCK, and other
variables), those stated below are essential.
GISDBASE
The GISDBASE is a directory in which all users’ GRASS data are stored. Within the GISDBASE, data are
segregated into subdirectories (called "projects") based on the map coordinate system used and the
geographic extent of the data. Each "project" directory itself contains subdirectories called
"mapsets"; each "mapset" stores "data base elements" - the directories (e.g., the cell, cellhd,
vector, etc., directories) in which GRASS data files are actually stored.
LOCATION_NAME
The user must choose to work with the data under a single GRASS project (previously called
"location") within any given GRASS session; this project is then called the current GRASS project,
and is specified by the variable LOCATION_NAME. The LOCATION_NAME is the GRASS data base location
whose data will be affected by any GRASS commands issued during the user’s current GRASS session, and
is a subdirectory of the current GISDBASE. Each "project" directory can contain multiple "mapset"
directories (including the special mapset PERMANENT). Maps stored under the same GRASS LOCATION_NAME
(and/or within the same MAPSET) must use the same coordinate system and typically fall within the
boundaries of the same geographic region.
MAPSET
Each "mapset" contains a set of maps relevant to the LOCATION_NAME directory in which it appears.
Each LOCATION_NAME can contain multiple mapsets. (Mapsets which fall under the same LOCATION_NAME all
contain data geographically relevant to the LOCATION_NAME, and all store data in the same map
coordinate system. Frequently, maps are placed into different mapsets to distinguish file ownership
- e.g., each user might have one or more own mapset(s), storing any maps that the user has created
and/or are relevant to the own work.) During each GRASS session, the user must choose one mapset to
be the current mapset; the current mapset setting is given by MAPSET, and is a subdirectory of
LOCATION_NAME. During a single GRASS session, the user can use available data in any of the mapsets
stored under the current LOCATION_NAME directory that are in the user’s mapset search path and
accessible by the user. However, within a single GRASS session, the user only has write access to
data stored under the current mapset (specified by the variable MAPSET).
Each "mapset" stores GRASS data base elements (i.e., the directories in which GRASS data files are
stored). Any maps created or modified by the user in the current GRASS session will be stored here. The
MAPSET directory PERMANENT is generally reserved for the set of maps that form the base set for all users
working under each LOCATION_NAME.
Once within a GRASS session, GRASS users have access only to the data under a single GRASS data base
directory (the current GRASS data base, specified by the variable GISDBASE), and to a single GRASS
project directory (the current project, specified by the variable LOCATION_NAME). Within a single
session, the user may only modify the data in the current mapset (specified by the variable MAPSET), but
may use data available under other mapsets under the same LOCATION_NAME.
All of these names must be legal names on the user’s current system.
The full path to the current mapset is determined from GISDBASE, LOCATION_NAME, MAPSET variables, in the
example above: /opt/grassdata/spearfish/PERMANENT. The full path can be printed using g.gisenv by
providing multiple variables:
g.gisenv get=GISDBASE,LOCATION_NAME,MAPSET sep=’/’
/opt/grassdata/nc_spm_08_grass7/user1
NOTES
The output from g.gisenv when invoked without arguments is directly usable by Bash. The following
command will cast each variable into the UNIX environment:
eval `g.gisenv`
This works only for Bash, sh, ksh, etc. The format of the output is not compatible with some other UNIX
shells.
By default the GRASS variables are stored in gisrc file (defined by environmental variable GISRC). If
store=mapset is given then the variables are stored in <gisdbase>/<project>/<mapset>/VAR after the
current GRASS session is closed.
EXAMPLES
Cache for raster operations
The maximum memory to be used, i.e. the cache size for raster rows, is set to 300 MB by default (GRASS
variable MEMORYMB). To speed up raster operations, it is recommended to increase this setting if enough
RAM is available. It is important to note that parallel processes will each consume this amount of RAM.
Set the maximum memory to be used (in MB), i.e. the cache size for raster rows:
# set to 6 GB (default: 300 MB)
g.gisenv set="MEMORYMB=6000"
Number of threads for parallel computing
Set the number of threads for parallel computing:
# set to use 12 threads (default: 1)
g.gisenv set="NPROCS=12"
GRASS Debugging
To print debugging messages, the variable DEBUG must be set to level equal or greater than 0:
g.gisenv set="DEBUG=3"
Levels: (recommended levels)
• 0 - silence
• 1 - message is printed once or few times per module
• 3 - each row (raster) or line (vector)
• 5 - each cell (raster) or point (vector)
To disable debugging messages:
g.gisenv unset="DEBUG"
The variable DEBUG controls debugging messages from GRASS libraries and modules.
Similarly WX_DEBUG controls debugging messages from wxGUI.
SEE ALSO
g.access, g.filename, g.findfile, g.mapsets
See also list of selected GRASS gisenv variables
AUTHOR
Michael Shapiro, U.S.Army Construction Engineering Research Laboratory
SOURCE CODE
Available at: g.gisenv source code (history)
Accessed: Friday Apr 04 01:18:53 2025
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GRASS 8.4.1 g.gisenv(1grass)