BSD-3-Clause licensed by Hideyuki Tanaka
Maintained by Michael Snoyman
This version can be pinned in stack with:process-conduit-,1855

Module documentation for

  • Data
    • Data.Conduit
      • Data.Conduit.ProcessOld
  • System
    • System.Process
      • System.Process.QQ

process-conduit: Conduit for processes


This package provides conduit for processes. Also this provides quasi-quoters for process using it.


$ cabal update
$ cabal install process-conduit


Haddock documents are here:

Quasi Quoters

process-conduit has three quasi-quoters, cmd, scmd and ccmd.

The result type of cmd is Lazy ByteString, but execution will perform strictly.

The result type of scmd and ccmd are GSource m ByteString and GConduit ByteString m ByteString respectively.

If a command is failed, an exception is thrown.

Commands are executed in run-time, not compile-time.


  • Create a Source and a Conduit of process
import Data.Conduit
import qualified Data.Conduit.Binary as CB
import Data.Conduit.Process
import System.IO

main :: IO ()
main = runResourceT $ do
  sourceCmd "ls" $= conduitCmd "sort" $$ CB.sinkHandle stdout
  • Invoke a process simply
{-# LANGUAGE QuasiQuotes #-}
import System.Process.QQ

main = print =<< [cmd|ls|]
  • Conduit Quasi-Quoters
main :: IO ()
main = runResourceT $ do
  [scmd|ls|] $= [ccmd|sort|] $$ CB.sinkHandle stdout
main = do
  [url] <- getArgs
  print =<< [cmd|curl #{url}|]