I don't completely understand the gemfile in a rails application

Question

What is the difference between installing a gem from the command line

sudo gem install gem-name

and writing your gem into the Gemfile and running bundle install?

I think the problem is that I don't understand the exact purpose of the Gemfile. So far it seems like it is a place to list all of the gems that your app is dependent on.

Answer 1

Installing a gem via:

sudo gem install gem-name

is going to install that gem system wide.

Whereas installing them via the Gemfile is specific for your rails app(to keep track of dependencies, version, app portability etc).