write.csv file= question

Hello,

I have a quick question about the ?file=? specification for the command
write.csv.    When I run this command in Rstudio I do not need the ?file=?
specified.  For example the below command works just fine.

write.csv(data,?/home/data.csv?)

However when I am running an Rscript from the terminal and putting it in
the background I need to specify ?file=?.  So for the example above I need
to instead have

write.csv(data,file=?/home/data.csv?)

Any ideas why this is the case?  Writing file= isn?t a problem, just
trying to get an idea of how R works better.

Thanks!