A recommendation for Homebrew as package manager for Mac OS X, offering easier installation of software than manual downloads. Explains how Homebrew manages dependencies and library locations under /usr/local, making it simple to install, update, and remove packages with single commands like brew install and brew uninstall.

Step-by-step installation guide for Scala, an object-oriented and functional programming language on the JVM. Covers downloading via curl or browser, verifying MD5 checksum, extracting with tar, moving to /usr/share, creating symbolic link for version management, updating .profile with SCALA_HOME and PATH, and verifying installation.

Similar installation process to Groovy/Grails, guiding through setting up JRuby on Mac OS X. Covers downloading tar.gz release, moving to /usr/share, creating symbolic link for easy version management, updating .profile with JRUBY_HOME environment variable and PATH, and noting that JRuby's gem command overrides standard Ruby's gem requiring full paths.

Step-by-step guide for installing Groovy and Grails on Mac OS X with symbolic links for easy upgrades. Covers downloading binary releases, moving to /usr/share, creating symbolic links to simplify version changes, updating .profile with GROOVY_HOME and GRAILS_HOME environment variables and PATH settings, and verifying installation.