How to enable auto completion in Ruby's IRB

Question

When I use Merb's built in console, I get tab auto-completion similar to a standard bash prompt. I find this useful and would like to enable it in non-merb IRB sessions. How do I get auto-completion in IRB?

Spleenful

Answer 1

Just drop require 'irb/completion' in your irbrc.

If that doesn't work try bond, http://tagaholic.me/bond/:

   require 'bond'; require 'bond/completion'

Bond not only improves irb's completion, http://tagaholic.me/2009/07/22/better-irb-completion-with-bond.html, but also offers an easy dsl for making custom autocompletions.

Ausgleich

Works great! Minor history bug in Git Bash, but I'm sure it will be fixed. – Gogetter

Just wanted to add, if you are on Ubuntu, you can create the file .irbrc in your $HOME directory if it doesn't already exist. – Mckinnie

Doesnt work on OSX 10.11.5 with irb version 0.9.6(09/06/30) – Peavey

Answer 2

This is just repeating the information on Cody Caughlan's comment above so it is easier to find:

either require 'irb/completion' or add the following to ~/.irbrc

IRB.conf[:AUTO_INDENT] = true
IRB.conf[:USE_READLINE] = true
IRB.conf[:LOAD_MODULES] = [] unless IRB.conf.key?(:LOAD_MODULES)
unless IRB.conf[:LOAD_MODULES].include?('irb/completion')
  IRB.conf[:LOAD_MODULES] << 'irb/completion'
end 

Spleenful

"the page above" is a little confusing, as the order of answers can be changed. You may wish to refer to answers by the author of those answers. – Veiled

Why should I add this block to the ibrc if a simple require statement does the same? – Rotow

@Rotow so you don't have to type require 'irb/completion' everytime you use or open irb =) – Drewdrewett

@M03, I parsed the sentence 'either require irb/completion or add the following to ~/.irbrc' as "either add require irb/completion to ~/.irbrc or add the following to ~/.irbrc'. I haven't used irb for years, but I still have a ~/.irbrc which indeed starts with require 'irb/completion' and doesn't include any LOAD_MODULES stuff. And with that a history file is loaded and written fine. – Rotow

Answer 3

This is what worked for me on Mac OS 10.11.5. using rvm. Do the following :

1. sudo gem install bond
2. Create the file .irbrc in your home directory. vi ~/.irbrc

3. Add the following lines in the .irbrc file require 'bond' Bond.start

4. Save and close the file

5. Open irb and use tab key to autocomplete

Peavey