unpack_command.md

The stack unpack command

stack unpack TARGET [--candidate] [--to DIR]

stack unpack downloads an archive file for one or more specified target packages from the package index (e.g. Hackage), or one or more specified target package candidates, and unpacks each archive into a subdirectory named after the package version.

In the case of packages from the package index, a target can be a package name only. In that case, by default:

• if Stack's --snapshot option is not specified, the download is for the most recent version of the package in the package index. Stack will first seek to update the index; and

• if Stack's --snapshot option is specified, the download is for the version of the package included directly in the specified snapshot.

!!! note

Stackage snapshots do not include directly most GHC boot packages (packages
that come with GHC and are included in GHC's global package database) but
some snapshots may include directly some boot packages. In particular, some
snapshots include directly `Win32` (which is a boot package on Windows)
while others do not.

Otherwise, a target should specify a package name and version (for example, acme-missiles-0.3). In the case of package versions from the package index, optionally, a revision in the package index can be specified by appending @rev:<number> or @sha256:<sha> (for example, acme-missiles-0.3@rev:0).

By default:

• the download is from the package index. Pass the flag --candidate to specify package candidates; and

  !!! note

  Stack assumes that a package candidate archive is a `.tar.gz` file named
  after the package version and located at endpoint
  `package\<package_version>\candidate\`. This is true of Hackage.
  

• the target is unpacked into a subdirectory of the current directory. Pass the option --to <directory> to specify an alternative destination directory to the current directory. The destination directory can be an absolute one or relative to the current directory.