Version 1.00.0 of popenhs is out. You can get it from: http://www.01.246.ne.jp/~juhp/haskell/popenhs/ popenhs is a small library providing lazy string output from and input to a subprocess. The interface provided by "popen" now differs from the "popen3" offered in 0.00 by taking an input string argument instead of returning an input handle. Thanks to Uwe Schmidt for reporting the problem in the previous release of popen3 hanging on a closed input pipe, that led to this new implmentation, which I believe fixes the problem. Jens