Ubuntu – How to set default to ruby 2.1.2

/usr/bin/env ruby should be pointing to the RVM ruby.

But lets check your setup

1. Check the contents of your ~/.profile, it should contain something like these 2 lines:

   export PATH="$PATH:$HOME/.rvm/bin" # Add RVM to PATH for scripting
   [[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm"  # This loads RVM
   

2. Second, check your installed ruby version:

   rvm list
   

   this should output something like the following:

   rvm rubies
   
   =* ruby-1.9.3-p286 [ x86_64 ]
   
   # => - current
   # =* - current && default
   #  * - default
   

   if not, try running rvm use 1.9.3 --default

3. When trying to run your script as root, be sure to use rvmsudo ./yourscript.rb instead of sudo ./yourscript.rb, this makes sure it sets the correct $PATH.

Let me know the outcome of the above three steps.

There are two ways of interactively using ruby on the command line (like running python or nodejs, for example):

Simply run ruby:

$ ruby
print "hello world\n"

Then press CtrlD. You will see:

hello world

The easier way is Interactive Ruby (irb):

$ irb
irb(main):001:0> print "hello\n"
hello
=> nil
irb(main):002:0>