[Rd] Possibly broken system2 env-option

peter dalgaard pd@|gd @end|ng |rom gm@||@com
Tue Mar 19 11:44:40 CET 2019

     On Windows, ‘env’ is only supported for commands such as ‘R’ and
     ‘make’ which accept environment variables on their command line.

So I suppose that would be tricky. 

The basic issue is that on Unix-alikes, system2 constructs a command like

FOO=bar cmd args

and passes that to sh via system(). On windoes, system() does not call sh, so system2() does (effectively)

cmd FOO=bar args

and hopes that cmd knows what to do with the env setting.


> On 19 Mar 2019, at 11:09 , Gábor Csárdi <csardi.gabor using gmail.com> wrote:
> On Tue, Mar 19, 2019 at 9:59 AM peter dalgaard <pdalgd using gmail.com> wrote:
> [...]
>> What you need is something like (NB: single quotes!)
>>> system2("sh", env = c("VAR='Hello World'"), args = c("-c 'echo $VAR'"))
>> Hello World
> Just out of curiosity, do you think it is possible to make this
> portable, assuming sh is available? On Windows it gives
>> system2("sh", env = c("VAR='Hello World'"), args = c("-c 'echo $VAR'"))
> /rtools34/bin/sh: VAR=Hello World: No such file or directory
> Warning message:
> running command '"sh" VAR='Hello World' -c 'echo $VAR'' had status 127
> G.

Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes using cbs.dk  Priv: PDalgd using gmail.com

More information about the R-devel mailing list