Load Error on Ruby 1.9.3 Mountain Lion - ruby

Question

I am new to Ruby and just installed Ruby 1.9.3. on my Moutnain Lion MacOSx with RVM and Homebrew.
After I installed Ruby, I wrote my first Tutorial Program (with text, textmate and Tincta) and saved it as a file.rb.
Now the problem is that i get this error message:
users-MacBook-Pro:~ user$ ruby calc.rb
ruby: No such file or directory -- calc.rb (LoadError)
The brew doctor command gives me this, but I don't even know if this has something to do with the issue:
Warning: /usr/bin occurs before /usr/local/bin
This means that system-provided programs will be used instead of those
provided by Homebrew. The following tools exist at both paths:
bashbug
gcov-4.2
git
git-cvsserver
git-receive-pack
git-shell
git-upload-archive
git-upload-pack
gitk
Consider amending your PATH so that /usr/local/bin
occurs before /usr/bin in your PATH.
Warning: Homebrew's sbin was not found in your path.
Consider amending your PATH variable so it contains:
/usr/local/sbin

Answer 1

Ruby is complaining that it can't find calc.rb. According to your description, you saved the file as file.rb, and then you tried to run calc.rb. Try ruby file.rb.
If that doesn't work, verify that ruby is working with
echo "puts 'hello'" | ruby
It should output hello. Then try running it from a file:
echo "puts 'hello'" > test.rb
ruby test.rb

Answer 2

A couple of things to troubleshoot from within your shell:
1 - Verify calc.rb exists:
ls calc.rb # will complain if calc.rb doesn't exist in the current directory
2 - Check where the ruby executable is being found:
which ruby # this might help narrow down issues with your $PATH
With regard to the homebrew issue, see if any of the following help:
brew doctor says “Error: /usr/bin occurs before /usr/local/bin” how to fix?
Where does $PATH get set in OS X 10.6 Snow Leopard? - still relevant in Mountain Lion AFAIK.