SHARDS(1)

NAME
shards - dependency manager for the Crystal Language

SYNOPSIS

shards [<general_options>...] [<command>] [<command_options>...]

DESCRIPTION

Manages dependencies for Crystal projects and libraries with reproducible installs across computers and systems.

USAGE

shards requires the presence of a shard.yml file in the project folder (working directory). This file describes the project and lists dependencies that are required to build it. See shard.yml(5) for more information on its format. A default file can be created by running shards init.

Running shards install resolves and installs the specified dependencies. The installed versions are written into a shard.lock file for using the exact same dependency versions when running shards install again.

If your shard builds an application, both shard.yml and shard.lock should be checked into version control to provide reproducible dependency installs. If it is only a library for other shards to depend on, shard.lock should not be checked in, only shard.yml. It’s good advice to add it to .gitignore.

COMMANDS

If no command is given, install command will be run by default.

To see the available options for a particular command, use --help after the command.

build [<targets>] [<build_options>...]
    Builds the specified <targets> in bin path. If no targets are specified, all are built. This command ensures all dependencies are installed, so it is not necessary to run shards install before.

    All <build_options> following the command are delegated to crystal build.

check
    Verifies that all dependencies are installed and requirements are satisfied.

    Exit status:

    0
        Dependencies are satisfied.

    1
        Dependencies are not satisfied.

init
    Initializes a default shard.yml in the current folder.

install [--frozen] [--without-development] [--production] [--skip-postinstall] [--skip-executables] [--jobs=N]
    Resolves and installs dependencies into the lib folder. If not already present, generates a shard.lock file from resolved dependencies, locking version numbers or Git commits.

    Reads and enforces locked versions and commits if a shard.lock file is present. The install command may fail if a locked version doesn’t match a requirement, but may succeed if a new dependency was added, as long as it doesn’t generate a conflict, thus generating a new shard.lock file.

    --frozen
        Strictly installs locked versions from shard.lock. Fails if shard.lock is missing.

    --without-development
        Does not install development dependencies.

    --production
        same as --frozen and --without-development

    --skip-postinstall
        Does not run postinstall of dependencies.

    --skip-executables
        Does not install executables.

    --jobs
        Number of repository downloads to perform in parallel (default: 8). Currently only for git.

list [--tree]
    Lists the installed dependencies and their versions.

    Specifying --tree arranges nested dependencies in a tree, instead of a flattened list.

lock [--update [<shards>...]]
    Resolves dependencies and creates or updates the shard.lock file as per the install command, but never installs the dependencies.

    Specifying --update follows the same semantics as the update command.

outdated [--pre]
    Lists dependencies that are outdated.

    When --pre is specified, pre-release versions are also considered.

prune
    Removes unused dependencies from lib folder.

update [<shards>...]
    Resolves and updates all dependencies into the lib folder, whatever the locked versions in the shard.lock file. Eventually generates a new shard.lock file.

    Specifying shards will update these dependencies only, trying to be as conservative as possible with other dependencies, respecting the locked versions in the shard.lock file.

version [<path>]
    Prints the current version of the shard located at path (defaults to current directory).

To see the available options for a particular command, use --help after a command.

GENERAL OPTIONS

--version
    Prints the version of shards.

-h, --help
    Prints usage synopsis.

--no-color
    Disables colored output.

--local
    Do not update remote repository cache. Instead, Shards will use the local copies already present in the cache (see SHARDS_CACHE_PATH). The command will fail if a dependency is unavailable in the cache.

-q, --quiet
    Decreases the log verbosity, printing only warnings and errors.

-v, --verbose
    Increases the log verbosity, printing all debug statements.

INSTALLATION

Shards is usually distributed with Crystal itself. Alternatively, a separate shards package may be available for your system.

To install from source, download or clone and run make CRFLAGS=--release. The compiled binary is in bin/shards and should be added to PATH.

ENVIRONMENT VARIABLES

SHARDS_OPTS
    Allows general options to be passed in as environment variable. Example: SHARDS_OPTS="--no-color" shards update

SHARDS_CACHE_PATH
    Defines the cache location. In this folder, shards stores local copies of remote repositories. Defaults to .cache/shards in the home directory ($XDG_CACHE_HOME or $HOME) or the current directory.

SHARDS_INSTALL_PATH
    Defines the location where dependencies are installed. Defaults to lib.

SHARDS_BIN_PATH
    Defines the location where executables are installed. Defaults to bin.

CRYSTAL_VERSION
    Defines the crystal version that dependencies should be resolved against. Defaults to the output of crystal env CRYSTAL_VERSION.

SHARDS_OVERRIDE
    Defines an alternate location of shard.override.yml.

FILES

shard.yml
    Describes a shard project including its dependencies. See shard.yml(5) for documentation.

shard.override.yml
    Allows overriding the source and restriction of dependencies. An alternative location can be configured with the env var SHARDS_OVERRIDE.

    The file contains a YAML document with a single dependencies key. It has the same semantics as in shard.yml. Dependency configuration takes precedence over the configuration in shard.yml or any dependency’s shard.yml.

    Use cases are local working copies, forcing a specific dependency version despite mismatching constraints, fixing a dependency, checking compatibility with unreleased dependency versions.

shard.lock
    Lockfile that stores information about the installed versions.

    If your shard builds an application, shard.lock should be checked into version control to provide reproducible dependency installs.

    If it is only a library for other shards to depend on, shard.lock should not be checked in, only shard.yml. It’s good advice to add it to .gitignore.

REPORTING BUGS

Report shards bugs to

Crystal Language home page:

COPYRIGHT

Copyright © 2025 Julien Portalier.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

AUTHORS

Written by Julien Portalier and the Crystal project.

SEE ALSO

shard.yml(5)