Ruby version manager is a great tool that allows you to easily have multiple versions of Ruby. For Unix-based environment, there is RVM and for Windows we have Pik. This post will take you to have a quick look on Pik.

Installation

When writing this post I am using ruby 1.9.1p429 (2010-07-02 revision 28523) [i386-mingw32] on Windows 7. You can use Pik from the Windows command line, Windows PowerShell, or Git Bash. Here I am using the command line. You can install pik via rubygems, or the Windows installer, or you can update pik with pik. Let us install pik using rubygems

gem install pik

If the installation gone smooth, you should see

Successfully installed pik-0.2.8
1 gem installed

After pik is installed now you want to use pik_install script to install the pik executable. You must install pik to a location in your path, but not in your Ruby bin directory. I add C:\bin to my path, so I run

pik_install C:\bin

then you should see

pik is installed

if you want to use pik with git bash, add the following line to your ~/.bashrc:
 [[ -s $USERPROFILE/.pik/.pikrc ]] && source $USERPROFILE/.pik/.pikrc

Update: the command prompt from which you run pik has to be started using run as Administrator (if it’s Windows 7). Pik is modifying %PATH% environment variable and Windows 7 would silently not let it do so if not enough user privileges. Now for the first time run

pik

and pik will print some message and at the top of the message you should see that pik was adding your current Ruby version

** Adding:  191: ruby 1.9.1p429 (2010-07-02 revision 28523) [i386-mingw32]
Located at:  C:\Ruby191\bin
...

Usage

To list all available pik commands, simply run

pik help commands

In this post I will show you how to add and use another Ruby version and how to handle gem

How to add and use another Ruby version

Let’s start with installing another Ruby version, I am installing Ruby 1.8.7 using rubyinstaller-1.8.7-p299.exe from RubyInstaller for Windows. During the installation, I was not mark the “Add Ruby executables to your PATH” option checked. After the install was done, I run

ruby -v

and see that Windows still using 1.9.1 version instead of 1.8.7. Now let’s add 1.8.7 to pik

pik add C:\Ruby187\bin
** Adding:  187: ruby 1.8.7 (2010-06-23 patchlevel 299) [i386-mingw32]
Located at:  C:\Ruby187\bin

Now run

pik list

to list available Ruby versions

  187: ruby 1.8.7 (2010-06-23 patchlevel 299) [i386-mingw32]
* 191: ruby 1.9.1p429 (2010-07-02 revision 28523) [i386-mingw32]

the * before 191 means that we are using Ruby 1.9.1 at the moment. Now let’s switch to Ruby 1.8.7

pik use 187

and then when you run "pik list" or "ruby -v" you will notice that we are using Ruby 1.8.7 instead of 1.9.1

How to handle gem

Before I install pik, I already install some gems (on Ruby 1.9.1) and when I switch to 1.8.7, gem list doesn’t recognize any gem installed previously (since it’s in different directory). Using pik you can install gem that will available on every Ruby versions on your environment

pik gem install win32console

now you should have win32console gem available on both versions or Ruby

ruby 1.8.7 (2010-06-23 patchlevel 299) [i386-mingw32]
Successfully installed win32console-1.3.0-x86-mingw32
1 gem installed

ruby 1.9.1p429 (2010-07-02 revision 28523) [i386-mingw32]
Successfully installed win32console-1.3.0-x86-mingw32
1 gem installed

Well, there you go, we’re now set up with multiple Rubies, just imagine the fun we can have :)