How can I capture stdout and stderr output from a process with Haskell turtle?

Question

{-# LANGUAGE OverloadedStrings #-}

import Turtle

runSh :: Text -> IO ()
runSh x = view $ inshell x empty

main :: IO ()
main = do
  runSh "echo 'abcxyz'"

I've got the above program which outputs:

Line "abcxyz"

Is there a way I can capture this text without being output to the shell's stdout?

Essentially, I'd like to run the process and get a [Line] value rather then a () value from the IO action.

Answer 1

This is possible with shellStrictWithErr.

{-# LANGUAGE OverloadedStrings #-}

import Turtle (empty, shellStrictWithErr, ExitCode)
import Data.Text (Text)

runSh :: Text -> IO (ExitCode, Text, Text)
runSh x' = shellStrictWithErr x' empty

main :: IO ()
main = do
  (e, v, v') <- runSh "ls"
  print e
  print v
  print v'