iruby no bash commands possible in jupyter notebook

Question

I am using iruby in my jupyter notebook and the kernel is working as expected and accepting all kind of ruby syntax

Unfortunately the %%bash command leads to an error. So no console commands are usable in my notebook. If i switch back to the basic python kernel, the %%bash commands are working as expected.

How can i achieve that the bash commands are working in the iruby kernel? Is there something I forgot to install or set up?

I use following settings in Ubuntu 20.04:

I also use rvm to manage my ruby version.

Basic setup

sudo apt install python3-pip python3-dev
sudo -H pip3 install --upgrade pip
sudo -H pip3 install virtualenv
pip install jupyter

Installing iruby

gem install ffi-rzmq
gem install iruby --pre
iruby register --force

setup and start

rvm use ruby-2.7.2
mkdir ~/ruby_notebook

virtualenv ~/ruby_notebook/ruby_env
source ~/ruby_notebook/ruby_env/bin/activate

jupyter notebook --notebook-dir ~/ruby_notebook

But following error occurs:

Any ideas how to solve this issue at all so that I can use bash commands?

======== UPDATE and Solution ======

Thanks to engineersmnky I found the solution:

like in python notebook I want to achieve following output:

with the command %x(ls -la) I get an execution but the output looks different like

So to get a correct output I added following:

%x(ls -la).each_line(chomp: true){|s| p s}

which comes close to the output but followed by an exection strinfg output in the notebook.

So my final solution, also to make the execution command less complicated I am using a method in the beginning of my notebook now.

def execute_console(input)
  %x(#{input}).each_line(chomp: true){|s| p s}
  return nil
end

This way I can execute special command sin my notebook using rails like

rails routes

in

execute_console('rails routes')

and the output is like expected without any string output.

Syntax errors are printed out as expected as well.

Answer 1

To execute commands at a system level you can use any of the following: Kernel#system, %x (see below for more about percent strings), or Kernel#` ("back ticks")

system('pwd')
%x(pwd) 
`pwd`

These will all run in process and return the output as a String.

If you want the commands to run in a separate process you can use other options such as IO.popen or fork { exec('pwd') } ( if supported by the OS)

TL;DR Why the error is occurring

Now to explain your actual error and why it is occurring.

This line is but %%bash is being interpreted by ruby and it is looking for a closing %. % is another way of creating a string literal (called a "Percent String").

The interesting part about this syntax is it does not really have a defined delimiter. (essentially most non-alphanumerics can open and close)

%{bash}
#=> "bash" 
%(bash)
#=> "bash"
%|bash| 
#=> "bash"

The last line of the docs states

If you are using “(”, “[”, “{”, “<” you must close it with “)”, “]”, “}”, “>” respectively. You may use most other non-alphanumeric characters for percent string delimiters such as “%”, “|”, “^”, etc.

In your case % is being used as the delimiter: e.g.

%%bash%
#=> "bash" 

but since there is no closing % this is being interpreted as:

%%bash
pwd 
--EOF--

Thus the error you are receiving because the String ("bash\npwd) is unterminated.