Hi, Code like: (or_, ow_) <- createPipe or <- fdToHandle or_ ow <- fdToHandle ow_ hSetBuffering ow LineBuffering hSetBuffering or LineBuffering h <- runProcess cmd [] Nothing Nothing Nothing (Just ow) Nothing In the cmd process, the ow is not LineBuffering.... -- 竹密岂妨流水过 山高哪阻野云飞