It is just a wrapper around fcsh. It allows to build flash/flex projects incrementally. It can be used from Makefile. The package contains two executables, hsfcsh and hsfcsh_do. The first one is daemon, hsfcsh_do allows to send commands to the daemon. Install - Install flex sdk and add /bin to your PATH - Install haskell platform, add ~/.cabal/bin to your PATH - `cabal install hsfcsh` Using Use `hsfcsh_do spawn` or `hsfcsh_do exit` to start or stop the daemon. Use `hsfcsh_do compile args` to compile something. It will spawn the daemon if it is not started yet. The next example will compile Start.mxml from the current directory: hsfcsh_do compile -- "$(PWD)/Start.mxml" The first time it may take few minutes to compile for large projects, but then it will compile the project incrementally. You can use hsfcsh_do from Makefile. See example in the corresponding directory. It will redirect compiler output to the stdout, so you could examine the results (errors, warnings, etc) or let your editor (vim, emacs) to parse them.