How to have multiple versions of Ruby AND Rails, and their combinations on Windows?

Question

Since Windows doesn\'t support rvm (Ruby version Manager), how do we have

• Ruby 1.8.7, Rails 2.3.8
• Ruby 1.8.7, Rails 3.0.0
• Ruby 1.9.2, Rai

Answer 1

I wrote myself a little batch file which creates a junction (aka symlinks) on the NTFS. The idea is to keep the PATH untouched. The path always contains c:\devkit\bin;c:\ruby\bin;.... The following Batch file changes the links to the actual directories.

@echo off
echo 1 - Ruby 1.9.3
echo 2 - Ruby 2.0.0 (32 bit)
echo 3 - Ruby 2.0.0 (64 bit)
choice /C 123 /M "Which Ruby? "

if errorlevel 255 goto confused
if errorlevel 3 goto 3
if errorlevel 2 goto 2
if errorlevel 1 goto 1
if errorlevel 0 goto 0
goto confused

:1
if exist c:\ruby rmdir c:\ruby
if exist c:\devkit rmdir c:\devkit
mklink /j c:\ruby c:\ruby193
mklink /j c:\devkit c:\devkit-4.5.2
goto end

:2
if exist c:\ruby rmdir c:\ruby
if exist c:\devkit rmdir c:\devkit
mklink /j c:\ruby c:\ruby2-x86
mklink /j c:\devkit c:\devkit-x64
goto end

:3
if exist c:\ruby rmdir c:\ruby
if exist c:\devkit rmdir c:\devkit
mklink /j c:\ruby c:\ruby2-x64
mklink /j c:\devkit c:\devkit-x64
goto end

:confused
echo I'm confused ...

:end
ruby -v