anquegi anquegi - 7 months ago 25
Bash Question

Ruby interactive shell commands

I want to make a ruby shell script that executes command from shell. What happens when the shell command needs the answer from a user?

For example, creating a new play framework application:

play new calimero

~ _ _
~ _ __ | | __ _ _ _| |
~ | '_ \| |/ _' | || |_|
~ | __/|_|\____|\__ (_)
~ |_| |__/
~
~ play! 1.2.7.2, http://www.playframework.org
~

~ The new application will be created in /home/anquegi/src/11paths/buildsdeb/toni_build/devops-tools/packaging/packwithruby/calimero
~ What is the application name? [calimero] ~ <=== here asks to the user


With ruby shell script, I want to prompt this to the user and get it, the ruby script waits for that, I press enter, and it works.

value = %x(play new calimero)


waits until the user clicks intro. How I should manage this? Should I print the question before it is made?

Answer

Original: http://stackoverflow.com/a/6488335/2724079

This can also be accomplished with IO.expect

require 'pty'
require 'expect'

PTY.spawn("play new calimero") do |reader, writer|
  reader.expect(/What is the application name/)
  writer.puts("\n")
end

This waits for the spawned process to display "What is the application name" and when it sees that prints a defined string (new line).