Go to the run
menu and choose Run...
Choose the button labeled ...
and locate the irb.bat
file which is located at path_to_ruby/bin/irb.bat
. Choose open
and it will display the path to irb in the text field.
After the irb path in the text field, enter -r "$(FULL_CURRENT_PATH)"
. The final text field should look something like:
C:\Ruby200\bin\irb.bat -r "$(FULL_CURRENT_PATH)"
Choose Save...
and you can setup a Shortcut for this Run. I chose F6
personally.
Now, write your Ruby file and hit F6
or whatever you set as the shortcut. IRb will then launch with your current Ruby file loaded into the environment.
Tutorials Point and Ruby Central have a list of some additional arguments you can pass to IRb that could also be used in the above example.
EDIT:
If you are more interested in running the IRb console from within Notepad++, You should check out the NppExec plugin. There is a good blog post on how to get it working for Python at Raza Sayed's blog. Just switch out Python for IRb.
A decent list of other Notepad++ plugins can be found on their wiki