You can download Crystal in a standalone .tar.gz file with everything you need to get started.

The latest files can be found on the Releases page at GitHub. Nightly builds are available as well at https://crystal-lang.org/install/nightlies/.

Download the file for your platform and uncompress it. Inside it you will have a bin/crystal executable.

To make it simpler to use, you can create a symbolic link available in the path:

ln -s /full/path/to/bin/crystal /usr/local/bin/crystal

Then you can invoke the compiler by just typing:

crystal --version