.TH g.gisenv 1grass "" "GRASS 6.4.4" "Grass User's Manual"
.SH NAME
\fI\fBg.gisenv\fR\fR  - Outputs and modifies the user's current GRASS variable settings.
.SH KEYWORDS
general, settings
.SH SYNOPSIS
\fBg.gisenv\fR
.br
\fBg.gisenv help\fR
.br
\fBg.gisenv\fR [\-\fBsn\fR]  [\fBget\fR=\fIVARIABLE\fR]   [\fBset\fR=\fIVARIABLE=value\fR]   [\fBstore\fR=\fIstring\fR]   [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Flags:
.IP "\fB\-s\fR" 4m
.br
Use shell syntax (for "eval")
.IP "\fB\-n\fR" 4m
.br
Don't use shell syntax
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.PP
.SS Parameters:
.IP "\fBget\fR=\fIVARIABLE\fR" 4m
.br
GRASS variable to get
.IP "\fBset\fR=\fIVARIABLE=value\fR" 4m
.br
GRASS variable to set
.IP "\fBstore\fR=\fIstring\fR" 4m
.br
Where GRASS variable is stored
.br
Options: \fIgisrc,mapset\fR
.br
Default: \fIgisrc\fR
.PP
.SH DESCRIPTION
When a user runs GRASS, certain variables are set specifying the GRASS
data base, location, 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.
.SH OPTIONS
No prompts are given to the user when running \fIg.gisenv\fR. If
run without arguments, \fIg.gisenv\fR lists all of the user's
current GRASS variable settings. Results are sent to standard output,
and may look like this:
\fC
.DS
.br
GISDBASE=/opt/grassdata/
.br
LOCATION_NAME=spearfish
.br
MAPSET=PERMANENT
.br
.DE
\fR
In this example, the full path name of the user's current location
(i.e., $LOCATION_NAME) is
/opt/grassdata/spearfish, and the full path name of the
user's current mapset (i.e., $MAPSET)
is /opt/grassdata/spearfish/PERMANENT.
.PP
If the user specifies a \fIvariable_name\fR 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 \fIvariables
list\fR for details.
.PP
While other variables may be associated with each GRASS session (e.g.,
GRASS_GUI, GIS_LOCK, and other variables), those stated below
are essential.
.IP "\fIGISDBASE\fR
.br
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
\(dqlocation" directory itself contains subdirectories called
\(dqmapsets"; each "mapset" stores "data base
elements" - the directories (e.g.,
the cell, cellhd, vector, etc., directories)
in which GRASS data files are actually stored.
.IP "\fILOCATION_NAME\fR
.br
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 \fIcurrent GRASS location\fR, 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").
.IP "\fIMAPSET\fR
.br
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 \fIcurrent mapset\fR; 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 \fIwrite\fR access to data
stored under the \fIcurrent mapset\fR (specified by the
variable $MAPSET).
.PP
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.
.PP
Once within a GRASS session, GRASS users have access only to the data
under a single GRASS data base directory (the \fIcurrent GRASS data
base\fR, specified by the variable $GISDBASE), and to a
single GRASS location directory (the \fIcurrent location\fR,
specified by the variable $LOCATION_NAME).  Within a single
session, the user may only \fImodify\fR the data in the
\fIcurrent mapset\fR (specified by the variable
$MAPSET), but may \fIuse\fR data available under other
mapsets under the same $LOCATION_NAME.
.PP
All of these names must be legal names on the user's current system.
.SH NOTES
The output from
\fIg.gisenv\fR
when invoked without arguments is directly usable by Bash.  The
following command will cast each variable into the UNIX environment:
\fC
.DS
.br
eval \(gag.gisenv\(ga
.br
.DE
\fR
This works only for \fIBash\fR. The format of the output is not
compatible with other UNIX shells.
.SS GRASS Debugging
To print debugging messages, the variable DEBUG must be set to level
equal or greater than 0:
\fC
.DS
.br
g.gisenv set="DEBUG=3"
.br
.DE
\fR
Levels: (recommended levels)
.RE
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)
.RE
To disable debugging messages, DEBUG must be set back to 0:
\fC
.DS
.br
g.gisenv set="DEBUG=0"
.br
.DE
\fR
.SH SEE ALSO
\fI
g.access,
g.filename,
g.findfile,
g.mapsets
\fR
.br
\fI
See also variables list
\fR
.SH AUTHOR
Michael Shapiro,
U.S.Army Construction Engineering Research Laboratory
.PP
\fILast changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $\fR
.PP
Full index
.PP
© 2003-2014 GRASS Development Team