[SOLVED]Ruby Popen3.open3 system command got stuck

Problem:

In Ruby, Open3.popen3 is a good way to execute a system command and get the output of the command. Following is the a piece of code that does this.


Open3.popen3(*cmd) do |stdin, stdout, stderr, wait_thread|
      err = stderr.gets
      out = stdout.gets
      [stdin, stdout, stderr].each{|stream| stream.send('close')}
      exit_status = wait_thread.value
end

It works well when your command throws some error to stderr. However, it got stuck forever if your command executes successfully without any error message, BECAUSE err=stderr.gets GOT STUCK.

Solution:

READ stdout FRIST

[SOLVED]Trouble-Shooting on Ruby on Rails Installation

1. Install ruby1.9.1 on Ubuntu
    Dependent on your OS version, you will have a default ruby version, which is usually outdated.
    Solution:
                  sudo apt-get install ruby1.9.1
                  sudo update-alternatives --config ruby
                  Select the number which corresponds to your newly installed ruby1.9.1 and enter
                  ruby -v, to see your current ruby version

2. Update rubygems
    On Debian Linux, "sudo gem update --system" is not allowed.
    Solution:
                  sudo gem install rubygems-update
         sudo update_rubygems
         sudo update-alternatives --config gem
                  Select the number which corresponds to your newly updated gem and enter
                  gem -v, to see your current gem version

3. Missing sqlite3, coffee-rails or some other gems
    Solution:
                 bundle install

4. rake db:create - Could not find a JavaScript runtime
    Solution:
                  sudo apt-get install nodejs
    Alternative solution(not work on Ubuntu 11.10):
                  Add following lines to Gemfile in your newly created app directory
                  "gem 'therubyracer'"
                  "gem ' libv8'"
                  Run "bundle install"

5. Installation of mysql2
    Solution:
                  sudo apt-get install libmysqlclient-dev
                  sudo gem install mysql2 -v '0.3.11'
                  Add following line to Gemfile
                  "gem 'mysql2'"

Tutorials

MySQL Python Tutorial
Ruby on Rails Tutorial
Install Ruby on Rails Using RVM