A different rubygem version for each ruby version in rvm - ruby

Question

I have ruby 1.8.7 and 1.9.3 installed by rvm. For each ruby version, I'd like to:
use gem 1.3.7 for ruby 1.8.7
use gem 1.8.x for ruby 1.9.3
How can I set the above in rvm?

Answer 1

$ rvm use 1.8.7
$ rvm rubygems 1.3.7
$ rvm use 1.9.3
$ rvm rubygems latest-1.8
$ gem -v
1.8.24
$ rvm use 1.8.7
$ gem -v
1.3.7

Answer 2

When install rvm and then rvm install ruby --version its taken latest rubygems version. So just follow the below steps:
rvm use 1.8.7
gem -v, e.g. shows 1.8.24 like that
If you want to use rubygems particular version only follow steps #3 and #4.
This is for syntax set the rubygems in rvm
rvm rubygems [x.y.z|latest-x.y|latest|remove]
Ex like this:
Retrieving rubygems-1.3.7
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 284k 100 284k 0 0 94166 0 0:00:03 0:00:03 --:--:-- 125k
Extracting rubygems-1.3.7 ...
Removing old Rubygems files...
Installing rubygems-1.3.7 for ruby-1.8.7-p371 ...
Installation of rubygems completed successfully.
then
gem -v => It shows 1.3.7
rvm rubygems 1.3.7
And If you want use any other version go to step #3
Ex: rvm rubygems latest

Answer 3

If you have already created gemsets in rvm for 1.3.7 and 1.8.x, skip this step. Otherwise, you need to create the gemset.
Here is how to create a gemset and then switch to it:
rvm 1.8.7 # switch to ruby 1.8.7
rvm gemset create 1.3.7 # you may have to do it this way: rvm --force rubygems 1.3.7
rvm gemset use 1.3.7 # use it
Next time you want to use ruby 1.8.7 with gemset 1.3.7 you only need to do this:
rvm use 1.8.7#1.3.7 # this sets the ruby version and gem version
ruby -v # checks the ruby version, should = 1.8.7
gem --version # checks the gemset version, should = 1.3.7
Repeat this for ruby 1.9.3 and gemset 1.8.x.
You can find out how to do this and find answers to questions other rvm related topics here: http://rvm.io/gemsets/using