Run R interactively from Rscript

Question

I'm trying to start a shiny app or an interactive .Rmd document from an Rscript. However, all I get is a message

Listening on http://127.0.0.1:...

I believe this is because R is running in interactive mode (another post about this). How can I write the proper Rscript so that either of the following would work?

My script

#!/usr/bin/Rscript

## This
library(shiny)
runApp(appDir = "../app")

## Or this
## rmarkdown::run("Main.Rmd")

Answer 1

If I understand your question correctly, I was able to achieve this with littler, which I use in lieu of Rscript for scripting tasks that revolve around R. I'm running CentOS 7, and based on the code in your question it looks like you are on a Unix-like machine, so installing littler should not be an issue. For minimal reproducibility, I used the default shiny application and shiny-based Rmarkdown templates provided by RStudio, saving them as testapp (the project / application directory name) and testRMD.rmd, respectively. Then, I have the following scripts:

---

testapp.r

#!/usr/bin/env r

shiny::runApp(
  "~/tmp/delete/testapp",
  port = 7088, 
  launch.browser = TRUE,
  host = "127.0.0.1")

---

testRMD.r

#!/usr/bin/env r

rmarkdown::run(
  file = "testRMD.rmd",
  dir = "~/tmp/delete",
  shiny_args = list(
    port = 7088,
    launch.browser = TRUE,
    host = "127.0.0.1"))

---

Set the permissions for these files so they can be executed -

[nathan@nrussell R]$ chmod +x testapp.r testRMD.r

(chmod +u ... should suffice, but regardless...), and you should be all set to run them from your terminal, etc...

---

[nathan@nrussell R]$ ./testapp.r
Loading required package: shiny

Listening on http://127.0.0.1:7088

[nathan@nrussell R]$ ./testRMD.r
Loading required package: shiny

Listening on http://127.0.0.1:7088

---

There is some additional command line output for the Rmd file that I omitted, but I'm sure this could be suppressed easily if desired. Anyhow, this seems to be working properly - both the shiny application and Rmarkdown application are interactive, just as when launched from RStudio - but if you had something else in mind please clarify.