Crystal by example: Hello World

A Hello World in Crystal is simple, just use the puts method to print values in the console.

You can use the Crystal compiler crystal run to run code directly.

puts "Hello, World!"

$ crystal run hello-world.cr

Hello, World!

If you want to generate a binary, compile and run the program using the crystal build command. The compiler will generate an executable, and you can also use additional options such as the --release flag to compile the program with optimizations.

$ crystal build --release hello-world.cr

./hello-world

Hello, World!