rc/profile for shell used in `system()`

[Ben2]

Hey all -
I need to load in some variables which can be accessed when calling system(), for example system("echo $PATH") - two questions:

• How can I add a variable thats available to the system call of RStudio, when launched from Finder (macOS)
• Does each call to system()launch a new shell, or is there one started when the RStudio session starts.

The shell within RStudio is bin/zsh. The solution needs to be portable as it will be recommended as a guideline for the company.

I have tried adding to ~/.shrc and ~/.shprofile to no avail.

thanks,

[t-kalinowski]

If you're primarily interested in setting env vars for processes that are launched via system() calls from R, then .Renviron is probably the best choice.

Using .Renviron to modify PATH in a way thats portable is a little tricky though because the PATH separator is different on Windows vs macOS/Linux (;, :). To modify PATH in a portable way, you might prefer doing it in .Rprofile, where you can access .Platform$path.sep. For example, placing something like this in .Rprofile:

local({

  set_path <- function(path, action = c("prefix", "suffix", "replace")) {
    action <- match.arg(action)
    new_entry <- normalizePath(as.character(path), mustWork = FALSE)
    path <- strsplit(Sys.getenv("PATH") -> old_path, 
                     .Platform$path.sep, fixed = TRUE)[[1]]
    path <- switch(action,
                   prefix = c(new_entry, path),
                   suffix = c(path, new_entry),
                   replace = new_entry)
    path <- paste0(path, collapse = .Platform$path.sep)
    Sys.setenv(PATH = path)
    invisible(old_path)
  }
  set_path("~/my-bin",  action = "prefix")

})

[Ben2]

This solves problem, I had no idea system processes loaded the .Renviron. Thank you for you help.