How do I source environment variables for a command shell in a Ruby script?

Question

I\'m trying to run some third party bash scripts from within my ruby program.

Before I can run them they require me to source a file. On the command line it all wor

Answer 1

I did this because I didn't want to have to write a file or mix up my ruby code with this stuff:

#!/usr/bin/env bash
eval $(echo "$(cat .env) $1" | tr '\n' ' ')

I put this in ~/bin/run_with_env.sh and then for example I can run:

% run_with_env.sh "rails console"

Answer 2

I'm not sure if I understand your question correctly. Do you try to source a shell script before running another one? In this case the answer is simple:

#!/bin/env ruby
system "source <path_to_source_file> && <command>"

If the source file contains variables which your command should use you have to export them. It is also possible to set environment variables within your Ruby script by using ENV['<name_of_var>'] = <value>.

---

Update: Jan 26, 2010 - 15:10

You can use IO.popen to open a new shell:

IO.popen("/bin/bash", "w") do |shell|
  shell.puts "source <path_to_source_file>"
  shell.puts "<command>"
end

Answer 3

Modifying ENV works only for a single thread and I do the below instead. But a question I have how do I use a merged COPY of the environment with IO.popen ? somehow it doesn't seem to work.

with "system" I can do:

# ... create new "path" here

    subEnv = Hash.new;
    subEnv.merge!(ENV); # copy old environment
    subEnv['PATH'] = path; # set new values in copy

    system(subEnv, commandLine);

Answer 4

Do this:

$ source whatever.sh
$ set > variables.txt

And then in Ruby:

File.readlines("variables.txt").each do |line|
  values = line.split("=")
  ENV[values[0]] = values[1]
end

After you've ran this, your environment should be good to go.

Answer 5

This is horrible, but..

env = %x{. /some/shell/script/which/setups/your/env && env}
env.split("\n").each do |line|
  key, value = line.split("=", 2)
  ENV[key] ||= value unless value.nil? or value.empty?
end