John & all, I use HSH in my project where several external programs and Haskell functions need to be piped together: HSH is of great help here. I however came across the situation when one of pipe-connected functions has signature IO (), yet it reads from stdin* and writes to stdout. The documentation mentions "instance ShellCommand (Handle -> Handle -> IO ())" which could be of some help, but in the latest version of HSH on Hackage this instance is commented out. What was the reason of doing that? Is this to be expected in the upcoming versions? Thank you. ---------------------------- * I modelled that by calling getContents, but the actual program will call a foreign library that contains a C function that reads from stdin (that is, FILE *), and that cannot be changed easily. -- Dimitry Golubovsky Anywhere on the Web