Maybe this is by design, but I just thought I would point this behavior out and ask for comment. test1 merely shows that runInteractiveCommand reacts differently to perl warnings than perl errors. Okay, maybe the inconsistency in that case is due to perl and not haskell. test2 behaves the same on win and nix. This is "pipe like" in that the ouptut of a command (which could be the result of a shell call, but just as easily be the return of a haskell function) gets fed into a shell command. In this case, if the shell command is simply "tail" the behavior is consistent from win to nix. test3 shows that the behavior stops being consistent if ssh enters the picture. (piping to tail via ssh). again, maybe this is due to ssh and not haskell. however... note however that on windows ghc -e 'mapM_ ( putStrLn . show ) [1..1000] ' | ssh `whoami`@localhost 'tail -n2' works fine. so it's not *just* ssh, but ssh in conjuction with runInteractiveCommand which seems to cause problems FWIW, using 10 lines instead of 1000 still hangs on windows. Is there a way to code up shell pipelike behavior in a more portable way? curious what the cafe thinks... thomas. import Test.HUnit import Misc ( (>>=^) ) import System.Process import System.IO import System.Exit -- works on linux, error on windows test1 = do res1 <- test_shellrunStderrOk runTestTT $ TestCase ( assertEqual "test1" "made it" res1 ) where test_shellrunStderrOk = do runprocessStdErrAllowed' "" cmdPerlwarn return "made it" cmdPerldie = " perl -e 'die \"error\"' " cmdPerlwarn = " perl -e 'warn \"blee\"' " -- works on linux, windows test2 = pipeTo "tail -n2" -- works on linux, hangs on windows test3 = pipeTo "ssh `whoami`@localhost 'tail -n2'" pipeTo cmd = do res2 <- test_shellrunPipeinLike runTestTT $ TestCase ( assertEqual ( "pipe to, cmd: " ++ cmd) (show l) res2 ) where test_shellrunPipeinLike = do runprocessStdErrAllowed' (unlines $ map show [1..l]) ( cmd ) >>=^ filter (not . ( == '\n') ) l = 1000 runprocessStdErrAllowed' inp s = do (ih,oh,eh,pid) <- runInteractiveCommand s so <- hGetContents oh se <- hGetContents eh hPutStrLn ih inp hClose ih ex <- waitForProcess pid case ex of ExitFailure e -> fail $ "shell command " ++ s ++ "\nFailed with status: " ++ show e _ | otherwise -> return so --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.