[GRASS5] update: html/env_vars.html

[Markus Neteler]

On Tue, Sep 23, 2003 at 01:25:36AM +0100, Glynn Clements wrote:
> 
> Markus Neteler wrote:
> 
> > trying to reduce confusion (hopefully I didn't increase it),
> > I have updated 
> >  html/env_vars.html
> > The list is split now into a list of env vars and GRASS vars 
> > 
> > So I hope that I got this right, otherwise please fix directly in CVS.
> 
> How did you try to determine which is which? Because a brief glance
> indicates that the method wasn't correct. E.g.

So we are approximating a correct file (the former version wasn't better
in my opinion).

> 1. GRASS_GUI is listed as an environment variable, but is actually a
> GRASS variable. Or, rather, it's meant to be a GRASS variable,
> although it appears that setting it in the environment will override
> any setting in $GISRC.

moved.
 
> 2. GISBASE and GISRC are listed as GRASS variables, but are actually
> environment variables. GISRC absolutely has to be an environment
> variable; given that it identifies the file which contains the values
> of the GRASS variables, it cannot itself be a GRASS variable.

moved.
 
> There are a few others that are definitely in the wrong category (but
> for most of them, I wouldn't know which category was correct without
> actually looking).
> 
> The most reliable way to check is to search the GRASS source tree
> (with find/fgrep) for occurrences of the string "getenv". If the
> variable name is passed to getenv(), it's an environment variable; if
> it's passed to G_getenv() or G__getenv() it's a GRASS variable (except
> for GISBASE, which is trapped by G__getenv()).
> 
> That leaves scripts. If a script uses e.g. `g.gisenv FOO`, then FOO is
> a GRASS variable. If it just uses $FOO, and doesn't use g.gisenv, then
> it's an environment variable. If it uses `eval g.gisenv`, shell
> variables will obtain their value from $GISRC if it includes a setting
> for that variable, and from the environment otherwise. A similar
> principle applies to Tcl/Tk scripts, only the syntax is different.

So any time someone comes across a bug in this file, he/she may feel 
free to fix it. It's in CVS and writable:
html/env_vars.html

Markus