Ruby 1.8 and 1.9 living together on Mac OSX

Lately I’ve been playing with Ruby 1.9.1 But for my professional life I still need 1.8.6 So here is how I have them setup to live happily together.

What you first want to do is, of course, install Ruby 1.9.1 (your tarball name might differ)

> wget ftp://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.1-p0.tar.gz
> tar xvf ruby-1.9.1-p0.tar.gz
> cd ruby-1.9.1-p0
> autoconf
> ./configure —prefix=/usr —enable-pthread
> make
Now before you install you should backup your current Ruby’s bin files…
> sudo cp /usr/bin/ruby /usr/bin/ruby-1.8
> sudo cp /usr/bin/irb /usr/bin/irb-1.8
> sudo cp /usr/bin/gem /usr/bin/gem-1.8

Okay, let’s continue with the install
> sudo make install

After this is complete confirm that Ruby 1.9.1 is installed
> ruby —version
> irb
> RUBY_VERSION
> exit

Now, because we’re assuming that you’ll most likely be usining 1.8.6 most of the time still let’s restore it and backup the bins for 1.9.1

> sudo mv /usr/bin/ruby /usr/bin/ruby-1.9
> sudo mv /usr/bin/ruby-1.8 /usr/bin/ruby
> sudo mv /usr/bin/irb /usr/bin/irb-1.9
> sudo mv /usr/bin/irb-1.8 /usr/bin/irb
> sudo mv /usr/bin/gem /usr/bin/gem-1.9
> sudo mv /usr/bin/gem-1.8 /usr/bin/gem

Now if you want an app to run with Ruby 1.9.1 just replace the first line of the script:

#!/usr/bin/ruby
with
#!/usr/bin/ruby-1.9

Happy Hacking!

> ./configure —program-suffix=19

The End