NAME

       g.gisenv  - Outputs and modifies the user's current GRASS variable settings.

KEYWORDS

       general, settings

SYNOPSIS

       g.gisenv
       g.gisenv help
       g.gisenv [-sn]  [get=VARIABLE]   [set=VARIABLE=value]   [store=string]   [--verbose]  [--quiet]

   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

       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.

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=spearfish
       MAPSET=PERMANENT
        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.

       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.

       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
       location  directory  (the  current  location, 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.

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. The format of the output is not compatible with other UNIX shells.

   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, DEBUG must be set back to 0:
       g.gisenv set="DEBUG=0"

SEE ALSO

        g.access, g.filename, g.findfile, g.mapsets
        See also variables list

AUTHOR

       Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

       Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $

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       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                     g.gisenv(1grass)