Ruby: How to load a file into interactive ruby console (IRB)?

Question

I am using IRB (interactive ruby console) to learn how to program with Ruby. How do I load a file into the console if I write my programs in a text editor first?

Solution 1

If you only need to load one file into IRB you can invoke it with irb -r ./your_file.rb if it is in the same directory.

This automatically requires the file and allows you to work with it immediately.

Solution 2

Using ruby 1.9.3 on Ubuntu 14.04, I am able to load files from the current directory into irb with the following command line:

irb -I . -r foo.rb

where foo.rb is the file I want to load from my current directory. The -I option is necessary to add the current directory (.) to ruby's load path, as explained in the ruby man page. This makes it possible to require files from the current directory, which is what the -r option to irb accomplishes.

The key piece that wasn't obvious for me when I had this problem is the -I option. Once you do that, you can call require 'foo.rb' from within irb for any files in the current directory. And of course, you can specify any directory you want, not just . with the -I option. To include multiple directories on the load path, separate them with a colon (:), e.g.:

irb -I foo/:bar/:baz/

This command will add the directories foo, bar, and baz to ruby's load path.

The final alternative is to use the relative or absolute path to the file when using require or -r to load a file:

irb -r ./foo.rb

or from within irb:

> require './foo.rb'

Solution 3

Type in irb

And then

require './ruby_file.rb'

This is assuming that ruby_file.rb is in the same directory. Adjust accordingly.

Solution 4

Two ways:

1. to load source without running the program -- this gives access to all variables and functions:

source("filename.rb")

2. to run program and then drop into interactive mode -- this only gives access to functions, not variables:

require("filename.rb")

Solution 5

It depends on your ruby. Ruby 1.8 includes your current path, while ruby 1.9 does not. Evaluate $: to determine if your path is included or not. So in ruby 1.9 you must use the entire path, which is always a safe bet.

Then you can use require or load to include the file.

require does not require you to add the suffix of the file when trying to find it and will only include the file once. require should be used instead of load most of the time.

Check out Adding a directory to $LOAD_PATH (Ruby) if you are going to be using ruby 1.8

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