crystal

Run a Crystal program

$ crystal run [path/to/file.cr]

$ crystal build [path/to/file.cr]

$ crystal build --release [path/to/file.cr]

$ crystal init app [project_name]

$ crystal spec

$ crystal tool format --check [path/to/file.cr]

$ crystal tool format [path/to/file.cr]

$ crystal docs

crystal [command] [options] [file] [--] [arguments]

crystal is the command-line interface for the Crystal programming language. Crystal is a statically-typed, compiled language with Ruby-inspired syntax that aims for C-level performance with programmer-friendly ergonomics.
The primary commands are run for quick execution during development and build for creating distributable binaries. Crystal compiles through LLVM, producing native machine code. The --release flag enables optimizations for production builds.
Crystal uses a specification-based testing framework. The spec command runs tests from the spec/ directory. The test syntax resembles RSpec from Ruby, making it familiar to Ruby developers.
The init command scaffolds new projects with standard directory structure, shard.yml (dependency manifest), and initial files. Dependencies (shards) are managed separately with the shards command, similar to Bundler in Ruby.
Crystal includes built-in code formatting and documentation generation. The playground provides an interactive web-based environment for experimenting with code.

run file

Compile and run the program.

Compile to an executable.

Run the project's spec test suite.

Create a new Crystal project (app or lib).

Generate API documentation.

Format Crystal source code.

Show type hierarchy.

Show implementation of a method.

Start the Crystal playground web server.

Compile in release mode with optimizations.

Specify output executable name.

Show compilation progress.

Disable colored output.

Define a compile-time flag.

Link statically.

Generate object file for cross-compilation.

Compilation can be slow and memory-intensive for large projects. Cross-compilation requires specific setup. Some Ruby syntax patterns don't translate directly. The standard library is smaller than more established languages. Static linking may require additional system libraries.

Crystal was created by Ary Borenszweig and Juan Wajnerman, with development starting in 2011 and the first public release in 2014. The language was designed to combine Ruby's expressiveness with static typing and native performance. Version 1.0 was released in March 2021, marking the language's production readiness.

shards(1), ruby(1), rustc(1), llvm(1)