Shake is a Haskell library for writing build systems - designed as a replacement for make. To use Shake the user writes a Haskell program that imports the Shake library, defines some build rules, and calls shake. Thanks to do notation and infix operators, a simple Shake program is not too dissimilar from a simple Makefile. However, as build systems get more complex, Shake is able to take advantage of the excellent abstraction facilities offered by Haskell and easily support much larger projects. The Shake library provides all the standard features available in other build systems, including automatic parallelism and minimal rebuilds. Shake provides highly accurate dependency tracking, including seamless support for generated files, and dependencies on system information (e.g. compiler version).