stack

Create new project

$ stack new [project_name]

$ stack build

$ stack run

$ stack test

$ stack ghci

$ stack install [package_name]

$ stack runghc [script.hs]

$ stack update

stack command [--resolver version] [options] [arguments]

stack is a build tool and project manager for Haskell. It provides reproducible builds by pinning GHC versions and package sets via Stackage snapshots.
Stackage snapshots (LTS or Nightly) define curated package sets known to build together. This avoids "dependency hell" by ensuring compatible versions. The resolver in stack.yaml specifies which snapshot to use.
Stack manages GHC installations automatically. Different projects can use different GHC versions without system-wide conflicts. The correct version downloads and builds on first use.
Project structure includes stack.yaml (configuration), package.yaml (package definition), and source directories. Templates provide starting points for libraries, executables, or specific frameworks.
The REPL (ghci) loads project code for interactive development. File watching (--file-watch) rebuilds on changes, enabling rapid iteration.
Integration with Cabal packages works through package.yaml or .cabal files. Stack can use Hackage packages not in Stackage via extra-deps.

new NAME [TEMPLATE]

Create new project.

Initialize stack in existing project.

Build project.

Build and run executable.

Build and run tests.

Build and run benchmarks.

Start REPL with project loaded.

Build and copy executables to bin.

Run command in build environment.

Clean build artifacts.

Upgrade stack itself.

Stackage snapshot (lts-19.0, nightly-2023-01-01).

Use system GHC instead of stack-managed.

Don't automatically install GHC.

Disable optimizations for faster build.

Enable test building.

Enable benchmark building.

Rebuild on file changes.

Additional GHC options.

Initial builds download GHC and many dependencies. Different from cabal workflow - teams should standardize. Stackage may lag behind Hackage for new releases. Disk space usage can be significant. Some advanced Cabal features require workarounds.

stack was created by FP Complete in 2015 to solve Haskell's dependency management challenges. It built on work from Stackage (stable package sets). The tool became widely adopted for its reproducibility guarantees and simplified workflow. Development continues with community involvement.

ghc(1), ghci(1), cabal(1), runghc(1)