Subprocess

A port of Python's excellent subprocess module to Ruby.

Many thanks to Bram Swenson, the author of the old subprocess gem, for graciously letting us use the name.

Installation

The recommended way of installing subprocess is through Rubygems:

$ gem install subprocess

You can also build subprocess from source by running:

$ gem build subprocess.gemspec

Usage

Most of the documentation for Python's subprocess module applies equally well to this gem as well. While there are a few places when our semantics differs from Python's, users of the Python module should largely feel at home using subprocess. We have attempted to document all of the differences, but if we have missed something, please file an issue.

A few examples:

require 'subprocess'

Check user's animal allegiances:

begin
  Subprocess.check_call(['grep', '-q', 'llamas', '~/favorite_animals'])
rescue Subprocess::NonZeroExit => e
  puts e.message
  puts "Why aren't llamas one of your favorite animals?"
end

Parse the output of uptime(1) to find the system's load:

load = Subprocess.check_output(['uptime']).split(' ').last(3)

Send mail to your friends with sendmail(1):

Subprocess.check_call(%W{sendmail -t}, :stdin => Subprocess::PIPE) do |p|
  p.communicate <<-EMAIL
From: alpaca@example.com
To: llama@example.com
Subject: I am so fluffy.

SO FLUFFY!
http://upload.wikimedia.org/wikipedia/commons/3/3e/Unshorn_alpaca_grazing.jpg
  EMAIL
end