Installing Scala on Linux

The following Scala installation steps are tested on my CrunchBang Linux 11 “Waldorf” machine.

1. Java Environment Check:
   Scala requires the Java runtime version 1.6 or later. So before you install Scala, first make sure that you Java environment is set up correctly.
   1. To test your Java runtime environment, type java -version at your command prompt and press ENTER. If your Java environment is set up correctly, you should see something like the following:

      ~$ java -version
      OpenJDK Runtime Environment (IcedTea 2.5.3) (7u71-2.5.3-2~deb7u1)
      OpenJDK Client VM (build 24.65-b04, mixed mode, sharing)
      

   2. Test to see that the Java compiler is properly installed. Type javac -version. You should see the compiler version if the compiler is found.

      ~$ javac -version
      javac 1.7.0_65
      

2. Scala Setup:
   1. Download Scala from www.scala-lang.org/download. The version I downloaded is Scala 2.11.4. You can get the binaries in tgz, deb, rpm, msi, or zip format depending on your preference and platform. I had chosen the tgz format for my installation.
   2. Unarchive the Scala binaries to a directory of your choice. I unachrive the downloaded file in my local bin directory.

      ~$ cd ~/bin
      ~/bin$ tar -zxvf ~/share/downloads/scala-2.11.4.tgz
      

      At this point, you can Start the Scala interpreter (aka the “REPL”) by launching scala from where it was unarchived, or tart the Scala compiler by launching scalac from the same location.

   3. Set Path and Environment. For quick access, add scala and scalac to your path. I do so by adding the following lines to the end of my ~/.bashrc file.

      export SCALA_HOME=~/bin/scala-2.11.4
      export PATH=$PATH:$SCALA_HOME/bin
      

      After this either open a new terminal window to activate the two new environmental variables, or reload your ~/.bashrc script with

      source ~/.bashrc

3. Test Your Scala Installation:
   Type scala -version, and scalac -version at the command prompt to test your Scala environment. You should see something like the following:

   ~$ scala -version
   Scala code runner version 2.11.4 -- Copyright 2002-2013, LAMP/EPFL
   ~$ scalac -version
   Scala compiler version 2.11.4 -- Copyright 2002-2013, LAMP/EPFL
   

4. Let’s try a simple command in the REPL. Invoke the REPL by typing scala, and enter the println command to say hello to your Scala installation. You can enter :help to find out more about the commands available in the REPL. Type in :q to quit the REPL when you are done.

   ~$ scala
   Welcome to Scala version 2.11.4 (OpenJDK Client VM, Java 1.7.0_65).
   Type in expressions to have them evaluated.
   Type :help for more information.
   
   scala> println("Hello, Scala!")
   Hello, Scala!
   
   scala> :q
   ~$