You are using it wrong. It wants strings of the form "name=value", not a
character vector with names as labels. So this is closer to the mark:
> system2("echo", env = c("VAR='Hello World'"), args = c("$VAR"))
>
However, as you see it doesn't work as intended. The problem is that the
$-substitution refers to the environment of the shell executing the command.
I.e. this does not work from a terminal command line either:
pd$ VAR="foo" echo $VAR
pd$
Or even
pd$ VAR="bar"
pd$ VAR="foo" echo $VAR
bar
What you need is something like (NB: single quotes!)
pd$ VAR="foo" sh -c 'echo $VAR'
foo
So:
> system2("sh", env = c("VAR='Hello World'"), args = c("-c 'echo $VAR'"))
Hello World
-pd
> On 18 Mar 2019, at 17:28 , Henning Bredel <h.bre...@gmx.de> wrote:
>
> Hey all,
>
> what is wrong with this command:
>
> system2("echo", env = c(VAR = "Hello World"), args = c("$VAR"))
>
> I am a bit confused, as help("system2") writes about the env option:
>
>> character vector of name=value strings to set environment variables.
>
> Is this option buggy, or am I using it just wrong?
>
> Thanks for your help
>
> Henning
>
> ______________________________________________
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--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd....@cbs.dk Priv: pda...@gmail.com
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