Print starting server message to stderr instead of stdout.

1 files changed, 3 insertions, 1 deletions

diff --git a/pandoc-cli/server/PandocCLI/Server.hs b/pandoc-cli/server/PandocCLI/Server.hs
index d2a1c9d3e..55cc9ffbd 100644
--- a/pandoc-cli/server/PandocCLI/Server.hs
+++ b/pandoc-cli/server/PandocCLI/Server.hs
@@ -18,6 +18,7 @@ import Network.Wai.Middleware.Timeout (timeout)
 import Safe (readDef)
 import System.Environment (lookupEnv)
 import Text.Pandoc.Server (ServerOpts(..), parseServerOptsFromArgs, app)
+import System.IO (stderr, hPutStrLn)
 
 -- | Runs the CGI server.
 runCGI :: IO ()
@@ -29,5 +30,6 @@ runCGI = do
 runServer :: [String] -> IO ()
 runServer args = do
   sopts <- parseServerOptsFromArgs args
-  putStrLn $ "Starting server on port " <> show (serverPort sopts) <> "..."
+  hPutStrLn stderr $
+    "Starting server on port " <> show (serverPort sopts) <> "..."
   Warp.run (serverPort sopts) (timeout (serverTimeout sopts) app)