Error with command line "rails server" on mac

Question

Whenever I use the command "rails server" in mac terminal, it prompts this error:

/Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- rubygems/format (LoadError)
    from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler/source.rb:5:in `<top (required)>'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler/dsl.rb:14:in `initialize'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler/dsl.rb:6:in `new'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler/dsl.rb:6:in `evaluate'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler/definition.rb:17:in `build'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler.rb:138:in `definition'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler.rb:126:in `load'
    from /Library/Ruby/Gems/2.0.0/gems/bundler-1.0.22/lib/bundler.rb:110:in `setup'
    from /Users/martindureja/Desktop/rails_projects/first_app/config/boot.rb:8:in `<top (required)>'
    from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from script/rails:5:in `<main>'

Answer 1

Looks like you have permission errors when trying to install your gems. If you don't want to worry about this in the future, use RVM.

https://rvm.io/