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<h2>GRASS variables and environment variables</h2>

There are two types of variables:
<ul>
<li><a href="#enviro">shell environment</a> variables,</li>
<li><a href="#gisenv">GRASS gisenv</a> variables.</li>
</ul>

There are a number of <i>shell</i> environment variable groups:
<ul>
<li><a href="#cairo">Cairo driver</a></li>
<li><a href="#png">PNG driver</a></li>
<li><a href="#ps">PS driver (PostScript)</a></li>
<li><a href="#html">HTMLMAP driver</a></li>
<li><a href="#dirrend">variables for direct rendering</a></li>
<li><a href="#internal">variables for internal use</a></li>
</ul>

Any setting which needs to be modifiable by a GRASS program (e.g. MONITOR)
has to be a GRASS <i>gisenv</i> variable.


<h2>GRASS-related Files</h2>

GRASS maintains some settings in a number of files on the system. They are
detailed <a href="#files">below</a>.


<h2>Setting environment variables</h2>

Setting environment variables depends on the shell being used:
<br><br>
Bash:
<div class="code"><pre>
export VARIABLE=value
</pre></div>
Csh:
<div class="code"><pre>
setenv VARIABLE value
</pre></div>
Cmd.exe (Windows):
<div class="code"><pre>
set VARIABLE=value
</pre></div>

<h2>Setting environment variables permanently</h2>

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


<h2>Setting GRASS variables</h2>

Use <em><a href="g.gisenv.html">g.gisenv</a></em> within GRASS. This permanently
predefines GRASS variables in the <tt>.grass7/rc</tt> file.
<br><br>
Usage:
<div class="code"><pre>
g.gisenv set="VARIABLE=VALUE"
</pre></div>

It looks unusual with two equals signs, but <em>g.gisenv</em> serves dual duty for
getting and setting GRASS variables.
<p>
If the user just specifies a variable name, it defaults to <b>get</b> mode.
For example:
<div class="code"><pre>
g.gisenv GRASS_GUI
text
</pre></div>

<a name="enviro"></a>
<h2>List of selected (GRASS related) environment variables</h2>

<blockquote>
[ To be set from the terminal shell or startup scripts ]
</blockquote>

<dl>
  
  <dt>GISBASE</dt>
  <dd>directory where GRASS lives. This is set automatically by the
    startup script.</dd>
  
  <dt>GISRC</dt>
  <dd>name of <tt>.grass7/rc</tt> file. Defines the system wide value
    while in a GRASS session.</dd>
  
  <dt>GRASS_ADDON_PATH</dt>
  <dd>[grass startup script]<br>
    allows to specify additional paths to local GRASS modules extra
    to standard distribution.</dd>
  
  <dt>GRASS_ADDON_ETC</dt>
  <dd>[libgis, g.findetc]<br>
    specify paths where support files (etc/) may be found external to
    standard distribution.</dd>
  
  <dt>GRASS_BATCH_JOB</dt>
  <dd>defines the name (path) of a shell script to be processed as batch job.</dd>

  <dt>GIS_ERROR_LOG</dt>
  <dd>If set, $GIS_ERROR_LOG should be the absolute path to the log file (a
   relative path will be interpreted relative to the process' cwd, not
   the cwd at the point the user set the variable). If not set,
   $HOME/GIS_ERROR_LOG is used instead. The file will only be used if
   it already exists.</dd>

  <dt>GRASS_ERROR_MAIL</dt>
  <dd>set to any value to send user mail on an error or warning that 
    happens while stderr is being redirected.</dd>
  
  <dt>GRASS_FONT_CAP</dt>
  <dd>[g.mkfontcap, d.font, display drivers]<br>
    specifies an alternative location (to $GISBASE/etc/fontcap) for 
    the font configuration file.</dd>
  
  <dt>GRASS_GNUPLOT</dt>
  <dd>[<!-- m.svfit, s.probplt, s.sv -->i.spectral]<br>
    program to use for plotting <em>gnuplot</em> data.</dd>
  
  <dt>GRASS_GUI</dt>
  <dd>either <tt>text</tt> or <tt>gui</tt> to define non-/graphical startup.
    <br><br>
    Can also specify the name of the GUI to use, e.g. <tt>wxpython</tt>
    (<em><a href="wxGUI.html">wxGUI</a></em>). 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.</dd>
  
  <dt>GRASS_HEIGHT</dt>
  <dd>[d.mon]<br>
    defines the height of GRASS monitor, see also GRASS_WIDTH.</dd>
  
  <dt>GRASS_HTML_BROWSER</dt>
  <dd>[init.sh, wxgui]<br>
    defines name of HTML browser. For most platforms this should be
    an executable in your PATH, or the full path to an executable.<br>
    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, i.e. 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):<br> &nbsp; &nbsp; <code>grep -A 1
      &quot;CFBundleIdentifier&quot;</code> <i>/path/to/application.app</i><code>/Contents/Info.plist</code><br>
    &nbsp; The signature is the &lt;string&gt; following the &lt;key&gt;,
    without the bracketing &lt;string&gt; tags.</dd>

  <dt>G_INFO_FORMAT_STANDARD</dt>
  <dd>[init.sh, wxgui]<br>
    sets percentage output and message formatting style to standard formatting.</dd>

  <dt>G_INFO_FORMAT_GUI</dt>
  <dd>[init.sh, wxgui]<br>
    sets percentage output and message formatting style to GUI formatting.</dd>

  <dt>G_INFO_FORMAT_SILENT</dt>
  <dd>[init.sh, wxgui]<br>
    disables percentage output and error messages.</dd>

  <dt>G_INFO_FORMAT_PLAIN</dt>
  <dd>[init.sh, wxgui]<br>
    sets percentage output and message formatting style to ASCII output without rewinding control characters.</dd>

  <dt>GRASS_INT_ZLIB</dt>
  <dd>[libgis]<br>
    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 <tt>compressed</tt> value of 2 in the
    cellhd file.
    <br><br>
    Obviously, decompression is controlled by the
    raster's <tt>compressed</tt> value, not the environment variable.</dd>
  
  <dt>GRASS_MESSAGE_FORMAT</dt>
  <dd>[various modules]<br>
    maybe set to either <tt>standard</tt> or <tt>gui</tt> (normally
    GRASS takes care).</dd>
  
  <dt>GRASS_MOUSE_BUTTON</dt>
  <dd>[various modules]<br>
    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 <tt>132</tt> will swap middle and right buttons. Note
    that this variable should be set before a display driver is initialized (e.g.,
    <tt>d.mon x0</tt>).</dd>
  
  <dt>GRASS_PAGER</dt>
  <dd>[various modules]<br>
    maybe set to either <tt>less</tt> or <tt>more</tt>.</dd>
  
  <dt>GRASS_PERL</dt>
  <dd>[used during install process for generating man pages]<br>
    set Perl with path.</dd>
  
  <dt>GRASS_RND_SEED</dt>
  <dd>set random seed
    for <em><a href="r.mapcalc.html">r.mapcalc</a></em> rand()
    function.</dd>
  
  <!-- HB Sept 2005: I don't think this exists anymore:
       <p>GRASS_STDERR
	 <br>&nbsp; set to any value to prevent user mail on error
	 -->
  <dt>GRASS_SH</dt>
  <dd>[shell scripts on Windows]<br>
    path to bourne shell interpreter used to run shell scripts.</dd>

  <dt>GRASS_SIGSEGV_ON_ERROR</dt>
  <dd>Raise SIGSEGV if an error occures]<br>
  This variable can be set for debugging purpose. The call
  of G_fatal_error() will end in a segmentation violation. GDB can be used
  to trace the source of the error.</dd>

  <dt>GRASS_PYTHON</dt>
  <dd>[wxGUI, Python Ctypes]<br>
    set to override Python executable.<br>
    On Mac OS X this should be the pythonw executable for the wxGUI to work.</dd>
  
  <dt>GRASS_VECTOR_LOWMEM</dt>
  <dd>[vectorlib]<br>
    If the environment variable GRASS_VECTOR_LOWMEM exists, memory
    consumption will be reduced when building vector topology
    support structures. Recommended for creating large vectors.</dd>

  <dt>GRASS_WXBUNDLED</dt>
  <dd>[wxGUI]<br>
    set to tell wxGUI that a bundled wxPython will be used.<br>
    When set, the wxGUI will not check the wxPython version, as this
    function is incompatible with a bundled wxPython.  It is up to the
    packager to make sure that a compatible wxPython version is bundled.</dd>
  
  <dt>GRASS_XTERM</dt>
  <dd>[lib/init/grass-xterm-wrapper, lib/init/grass-xterm-mac]<br>
    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.</dd>
  
  <dt>GRASS_UI_TERM</dt>
  <dd>set to any value to use the terminal based parser.</dd>

  <dt>GRASS_VERSION</dt>
  <dd>reports the current version number (used by R-stats interface etc);
    should not be changed by user.</dd>
  
  <dt>GRASS_WIDTH</dt>
  <dd>[d.mon]<br>
    defines the width of GRASS monitor, see also GRASS_HEIGHT.</dd>
  
  <dt>GRASS_NO_GLX_PBUFFERS</dt>
  <dd>[nviz]<br>
    set to any value to disable the use of GLX Pbuffers.</dd>
  
  <dt>GRASS_NO_GLX_PIXMAPS</dt>
  <dd>[nviz]<br>
    Set to any value to disable the use of GLX Pixmaps.</dd>
</dl>

<a name="cairo"></a>
<h3>List of selected GRASS Cairo driver environment variables</h3>

<blockquote>
[ These variables control the function of the Cairo driver. ]
</blockquote>

See <a href="cairodriver.html">Cairo driver</a> manual page for detailed
list of the variables.

<a name="png"></a>
<h3>List of selected GRASS PNG driver environment variables</h3>

<blockquote>
[ These variables control the function of the PNG driver. ]
</blockquote>

See <a href="pngdriver.html">PNG driver</a> manual page for detailed
list of the variables.

<a name="ps"></a>
<h3>List of selected GRASS PS driver environment variables</h3>

<blockquote>
[ These variables control the function of the PS driver. ]
</blockquote>

See <a href="psdriver.html">PS driver</a> manual page for detailed
list of the variables.

<a name="html"></a>
<h3>List of selected HTMLMAP driver environment variables</h3>

<blockquote>
[ These variables control the function of the HTMLMAP driver. ]
</blockquote>

See <a href="htmldriver.html">HTMLMAP driver</a> manual page for
detailed list of the variables.

<a name="dirrend"></a>
<h3>List of selected GRASS environment variables for direct rendering</h3>
<blockquote>
[ In addition to those which are understood by the
 <a href="pngdriver.html">PNG driver</a>, the following variables
 affect direct rendering. ]
</blockquote>

<dl>

  <dt>GRASS_RENDER_IMMEDIATE</dt>
  <dd>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 
    <tt>d.mon&nbsp;start=PNG</tt>.</dd>
  
  <dt>GRASS_FONT</dt>
  <dd>specifies the font as either the name of a font from
    $GISBASE/etc/fontcap (or alternative fontcap file specified by GRASS_FONT_CAP),
    or alternatively the full path to a FreeType font file.</dd>
  
  <dt>GRASS_ENCODING</dt>
  <dd>the encoding to be assumed for text which is drawn using a
    freetype font; may be any encoding know to <em>iconv</em>.</dd>
</dl>

<a name="internal"></a>
<h3>List of selected internal GRASS environment variables</h3>
<blockquote>
  [ These variables are intended <b>for internal use only</b> by the GRASS
  software to facilitate communication 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. ]
</blockquote>

<dl>
  <dt>GRASS_OVERWRITE</dt>
  <dd>[all modules]<br>
    toggles map overwrite.
    <ul>
      <li>0 - maps are protected (default),</li>
      <li>1 - maps with identical names will be overwritten.</li>
    </ul>
    This variable is automatically created
    by <em><a href="g.parser.html">g.parser</a></em> so that the
    <tt>--overwrite</tt> option will
    be inherited by dependent 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.</dd>
  
  <dt>GRASS_VERBOSE</dt>
  <dd>[all modules]<br>
    toggles verbosity level
    <ul>
      <li>0 - only errors and warnings are printed</li>
      <li>1 - progress messages are printed (percent complete)</li>
      <li>2 - all module messages are printed</li>
      <li>3 - additional verbose messages are printed</li>
    </ul>
    This variable is automatically created by <em><a href="g.parser.html">g.parser</a></em>
    so that the <tt>--verbose</tt> or <tt>--quiet</tt> flags will be inherited
    by dependent modules as the script runs.</dd>
  
  <dt>GRASS_REGION</dt>
  <dd>[libgis]<br>
    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.</dd>
  
  <dt>WIND_OVERRIDE</dt>
  <dd>[libgis]<br>
    it causes programs to use the specified named region (created with
    e.g. <tt>g.region save=...</tt>) to be used as the current region, instead of
    the region from the WIND file.<br><br>
    This allows programs such as the GUI to run external commands on an
    alternate region without having to modify the WIND file then change it
    back afterwards.</dd>
</dl>

<a name="gisenv"></a>
<h2>List of selected GRASS gisenv variables</h2>

<blockquote>
  [ Use <em><a href="g.gisenv.html">g.gisenv</a></em> to get/set/unset/change them ]
</blockquote>

<dl>
  
  <dt>DEBUG</dt>
  <dd>[entire GRASS]<br>
    sets level of debug message output (0: no debug messages)
<div class="code"><pre>
g.gisenv set=DEBUG=0
</pre></div>

  <dt>WX_DEBUG</dt>
  <dd>[wxGUI]<br>
    sets level of debug message output for <em><a href="wxGUI.html">wxGUI</a></em> (0: no debug messages, 1-5 debug levels)
  
  <dt>GISDBASE</dt>
  <dd>initial database</dd>

  <dt>GIS_LOCK</dt>
  <dd>lock ID to prevent parallel GRASS use,
    <br>process id of the start-up shell script</dd>
  
  <dt>GRASS_DB_ENCODING</dt>
  <dd>[d.what.vect/forms library]<br>
    encoding of query form (utf-8, ascii, iso8859-1, koi8-r)</dd>
  
  <dt>GRASS_GUI</dt>
  <dd>either <tt>text</tt> or <tt>gui</tt> to define non-/graphical startup.
    <br><br> Can also specify the name of the GUI to use,
    e.g. <tt>wxpython</tt>
    (<em><a href="wxGUI.html">wxGUI</a></em>). Also exists as a shell
    environment variable. 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.</dd>
  
  <dt>LOCATION</dt>
  <dd>full path to location directory</dd>
  
  <dt>LOCATION_NAME</dt>
  <dd>initial location name</dd>
  
  <dt>MAPSET</dt>
  <dd>initial mapset</dd>
  
  <dt>OVERWRITE</dt>
  <dd>[all modules]<br>
    toggles map overwrite.
    <ul>
      <li>0 - maps are protected (default),</li>
      <li>1 - maps with identical names will be overwritten.</li>
    </ul>
    This variable is automatically created
    by <em><a href="g.parser.html">g.parser</a></em> so that the
    <tt>--overwrite</tt> option will
    be inherited by dependent 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.</dd>
</dl>

<a name="files"></a>
<h2>GRASS-related Files</h2>

<dl>
  <dt>$HOME/.grass7/rc</dt>
  <dd>stores the GRASS variables (but not environment variables)</dd>
  
  <dt>$HOME/.grasslogin7</dt>
  <dd>stores the DBMI passwords in this hidden file.
    Only the file owner can access this file.</dd>

  <dt>$HOME/GIS_ERROR_LOG</dt>
  <dd>if this file exists then all GRASS error and warning messages are 
    logged here. Applies to current user. To generate the file, use:
    <tt>touch $HOME/GIS_ERROR_LOG</tt><br>
   See also GIS_ERROR_LOG variable.</dd>
  
</dl>

<h3>SEE ALSO</h3>

<em>
  <a href="displaydrivers.html">Display drivers</a>
  <br>
  <a href="g.gisenv.html">g.gisenv</a>,
  <a href="g.parser.html">g.parser</a>
</em>

<p>
<i>Last changed: $Date$</i>

<hr>

<p>
<a href=index.html>Help Index</a>
<p>
&copy; 2008 <a href="http://grass.osgeo.org">GRASS Development Team</a>

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