Run Haskell source files as shell scripts

To run a Haskell source file as a shell script, add one of the following blocks to the top of your source file:

With runhaskell: ¹

#!/usr/bin/env runhaskell

With cabal: ¹

#!/usr/bin/env cabal
{- cabal:
build-depends: base
-}

With stack: ²

#!/usr/bin/env stack
-- stack script

Then, mark the script as executable: chmod u+x example.hs

Footnotes