Shellator

Shelling out in Ruby is way harder than it should be. Shellator, which is in part a gem just because it's a good name, wraps Open.popen3 in a consistent, mostly-not-dumb way.

I've been dragging around a variant of this blog post for about three years now and finally, finally, I have shamed myself into packaging it as a library for use by friends, enemies, minions, and miscellaneous alike.

Enjoy.

Installation

Add this line to your application's Gemfile:

gem 'shellator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install shellator

Usage

Non-interactive commands

require 'shellator'

Shellator.noninteractive("docker build .",
                         stdout: ->(line) { puts line },
                         stderr: ->(line) { puts line })

Providing non-interactively

stdin_content is optional. A newline will be appended after the content is written to the subprocess stdout unless stdin_newlines is set to false.

require 'shellator'

Shellator.noninteractive("cat | tr abcdef ABCDEF",
                         stdin_content: ["a b c", "d e f"],
                         stdout: ->(line) { puts line },
                         stderr: ->(line) { puts "ERR: #{line}" })

# Output (on stdout):
# A B C
# D E F

Shellator.noninteractive("cat | tr abcdef ABCDEF",
                         stdin_content: ["a b c", "d e f"],
                         stdin_newlines: false,
                         stdout: ->(line) { puts line },
                         stderr: ->(line) { puts "ERR: #{line}" })

# Output (on stdout):
# A B CD E F

Interactive commands

Not currently supported. If there was demand for this, I'd like to figure out a way to weld the popen3 approach to something like PTY for an Expect-like experience.

That also probably means a state machine.

Suggestions/pull requests gratefully solicited.

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/eropple/shellator. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Shellator project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.