[R] Sys.getenv

[Peter Dalgaard BSA]

Christian Hoffmann <christian.hoffmann at lagonda.wsl.ch> writes:

> I am running R-1.3.0 on Solaris 8:
                                 ?? (see below)
> 
> Under Solaris I do
> setenv dendro_us hoffmann
> 
> echo $dendro_us gives back:
> hoffmann
> 
> which is correct.
> 
> When in R I do:
> 
> Sys.getenv("dendro_us")  I get
> dendro_us 
>        "" 
> 
> which is NOT correct:
> 
> Inverse effect (taken from help of Sys.getenv)
> Under R:
> print(Sys.putenv("R_TEST"="testit", ABC=123))
> [1] TRUE TRUE
> Sys.getenv("R_TEST")   gives back:
>   R_TEST 
> "testit" 
> which seems correct.
> 
> When in Solaris I do:
> echo $R_TEST
> R_TEST: Undefined variable.
> 
> which is NOT correct:
> 
> Third type of behaviour:
> echo $HOME
> /home/woodstock/hoffmann
> and
> Sys.getenv("HOME")
>                       HOME 
> "/home/woodstock/hoffmann" 
> 
> which are both correct.
> 
> QUESTION:
> Are there two versions of the environment around? Or what am I missing?

It's not quite clear to me exactly what you're doing, but the thing
that usually confuses people about environments is the following:

Environments exist on a per-process basis. A child process inherits a
*copy* of the parent environment. Making changes to an environment
does not affect the environment of any other running process.

E.g. the following is expected:

> Sys.putenv("FOO"="bar")
> system("echo $FOO")
bar
> q("no")
$ echo $FOO

$ 
but this should work (parallel to setenv but Bourne shell syntax):


$ BAR=foo ; export BAR
$ R --quiet
> Sys.getenv("BAR")
  BAR 
"foo" 


> >uname -a
> SunOS fluke 5.7 Generic_106541-12 sun4d sparc SUNW,SPARCserver-1000
              ??? (that'd make it Solaris 7, no?)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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