Im having trouble installing Ruby on my Mavericks

Question

lakshmis-MacBook-Pro:~ lakshmishanthappa$ rvm install 2.0.0
Searching for binary rubies, this might take some time.
Found remote file https://rubies.travis-ci.org/osx/10.9/x86_64/ruby-2.0.0-p481.tar.bz2
Checking requirements for osx.
/usr/local/bin/brew: /usr/local/Library/brew.rb: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby: bad interpreter: No such file or directory
/usr/local/bin/brew: line 23: /usr/local/Library/brew.rb: Undefined error: 0
ERROR: '/bin' is not writable - it is required for Homebrew, try 'brew doctor' to fix it!
Requirements installation failed with status: 1.
lakshmis-MacBook-Pro:~ lakshmishanthappa$ rvm install 1.9.3
Searching for binary rubies, this might take some time.
No binary rubies available for: osx/10.9/x86_64/ruby-1.9.3-p547.
Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
Checking requirements for osx.
/usr/local/bin/brew: /usr/local/Library/brew.rb: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby: bad interpreter: No such file or directory
/usr/local/bin/brew: line 23: /usr/local/Library/brew.rb: Undefined error: 0
ERROR: '/bin' is not writable - it is required for Homebrew, try 'brew doctor' to fix it!
Requirements installation failed with status:
This is what I get always .

Answer 1

Install homebrew. Then brew update followed by brew upgrade. Leave it alone. RVM will look for the presence of this package manager, and will use it to install any missing dependencies when installing RVM itself or new versions of Ruby that need to be compiled.
Without system privileges, just perform the rvm curl install into your home directory. Everything gets stuffed into ~/.rvm hierarchy.
In the Terminal, to see latest Rubies.
rvm list | more
Although OS X 10.9.3 updated MRI Ruby to 2.0.0p451, a 2.0.0p481 and 2.1.2 release are now available.
rvm install 2.0.0p481
rvm use 2.0.0p481 --default
rvm list
gem update
Verify that your .bashrc file has this new Ruby path included.
export PATH=$HOME/.rvm/gems/ruby-2.0.0/bin:.:/usr/local/bin:$PATH
and at the end of the .bashrc file:
export PATH=$PATH:$HOME/.rvm/bin
[ -s $HOME/.rvm/scripts/rvm ] && source $HOME/.rvm/scripts/rvm
It is a good idea to keep RVM current.
rvm get stable
Though unrelated to RVM, I would also do a softlink of the old Ruby-Cocoa v1.8.7 version.
ln -s /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby ~/bin/ruby18
Apple did not bake any Objective-C/Cocoa support into Ruby 2.0. It is in the older version above.