Note: This document is for an older version of GRASS GIS that is outdated. You should upgrade, and read the current manual page.

NAME

KEYWORDS

SYNOPSIS

Flags:

-s

Use shell syntax (for "eval")

-n

Don't use shell syntax

--verbose

Verbose module output

--quiet

Quiet module output

Parameters:

get=VARIABLE

GRASS variable to get

set=VARIABLE=value

GRASS variable to set

store=string

Where GRASS variable is stored

Options: gisrc,mapset

Default: gisrc

DESCRIPTION

OPTIONS

GISDBASE=/opt/grassdata/
LOCATION_NAME=spearfish
MAPSET=PERMANENT

If the user specifies a variable_name on the command line (e.g., 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.

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 "locations") based on the map coordinate system used and the geographic extent of the data. Each "location" 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 location within any given GRASS session; this location is then called the current GRASS location, 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 "location" 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 (aka, "location").

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 his own mapset, storing any maps that he has created and/or are relevant to his 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.

All of these names must be legal names on the user's current system.

NOTES

eval `g.gisenv`

GRASS Debugging

g.gisenv set="DEBUG=3"

g.gisenv set="DEBUG=0"