Download and install Racket, which includes DrRacket. (Of course, you’re welcome to use your preferred text editor, but the tutorials will assume you’re using DrRacket.)
Linux and OS X users: update your system PATH to include "/path-to-racket-installation/bin/". Then, from the terminal, you’ll be able to run racket and raco (see raco: Racket Command-Line Tools).
OS X users who haven’t altered your PATH before: don’t panic. You need to add the full path to Racket’s bin directory to the "/etc/paths" file on your system. You can do this with the following terminal command (which will ask you for your password):
To check that you did it correctly, try typing racket on your command line, and you should see something like this:
~ : racket
Welcome to Racket v.6.6.
Type ctrl+D to exit.
But if you get an error like this:
Unrecognized command: racket
You have a deeper problem with your Racket installation that needs adjustment before continuing (usually a misconfiguration of PATH).
Then, from the command line, install Pollen:
raco pkg install pollen
To check that it worked, try typing raco pollen test on the command line, and you should see this:
~ : raco pollen test
raco pollen is installed correctly