how does gem installation works ? how did gem get the installation files?

when I wanted to install SASS, I have been told to install ruby on my machine, ok fine.

then all I had to do is to run the following code

gem install sass

and now I am done, and I have开发者_如何转开发 SASS installed

my question is in general..

How did gem knows what SASS is, and from where did it get it ?

It is a cool thing but I just want to know what happened behind the scenes ?

Thanks

---

RubyGems is a package manager like many others. It depends on a central repository to host installable packages. The command line tool fetches these packages from the central repository and installs them.

See RubyGems FAQ and Introduction.