[R] quotes in Rscript -e through system

[Uwe Ligges]

On 24.05.2012 12:58, abhagwat wrote:
> I figured out how to use quotes and parentheses when using Rscript -e (on a
> bash shell):
> Rscript -e write\(1,\"a.txt\"\)
>
> -->  Question 1: why do the parentheses need to be escaped in the shell?
> (More a shell than an R question)

Because the shell shopudl not interpret quotes and parantheses but pass 
all the string to R.


>
> Then I figured out how to use quotes and parentheses when calling Rscript
> through system:
> system('Rscript -e write\\(1,\\\'a.txt\\\'\\)')
>
> -->  Question 2: why exactly is it necessary to use double and triple
> escapes? I kinda understand it, but not completely.

double: \ is a special character in R that escapes the second \

triple: actually a double \ for the reason geiven above, and then \' for 
protecting the ' to be evaluated (i.e. indicating the end of the former 
' before the Rscript).

Uwe Ligges






> Thanks for your insights!
>
> Adi
>
>
>
>
>
> --
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