How to Find Which Operating System My Ruby Program Is Running On

What's the best-practice way to find out the platform ruby is running on?

There's always:

begin
  require 'win32console'
rescue LoadError
end

I find this easier to write and reason about that trying to decide for myself which OS I'm on and whether or not to load it.

Update: I was thinking win32console was built-in rather than a gem. I believe Win32API is available on all Windows installs, so it's a good proxy to test "Is this Windows?" (rather than "What OS is this, and is that Windows?").

begin
  require 'Win32API'
  windowsOS = true
rescue LoadError
  windowsOS = false
end

if windowsOS
  begin
    require 'win32console'
  rescue LoadError
    # Prompt user to install win32console gem
  end
end

How do I ask Ruby what system it's running on?

You can use the RUBY_PLATFORM constant to inquire:

>> RUBY_PLATFORM
=> "i686-linux"

For this purpose we have used code similar to https://github.com/kotp/rlcw/blob/master/lib/platform.rb:

module Platform

  def check_operating_system
    # The Mac check has to be proceed before the Win check!
    # Perhaps checking for /mswin/ will reduce this requirement.
    case RUBY_PLATFORM
    when /ix/i, /ux/i, /gnu/i, /sysv/i, /solaris/i, /sunos/i, /bsd/i
      require 'gtk2'
      Gtk.init
      @clip = Gtk::Clipboard.get(Gdk::Selection::CLIPBOARD)
      :unix
    when /darwin/i
      :mac_os_x
    when /mswin/i, /ming/i
      require 'vr/clipboard'
      @clip = Clipboard.new(2048)
      :windows
    else
      :other
    end
  end

end

Checking if a program is running

Here's a contrived example that uses tasklist. It assigns the result of the backtick system call to a status variable. If this variable is empty, then the specified program isn't running.

def find_process
  status = `tasklist | find "notepad.exe"`
  if status.empty?
    puts "Process is not running"
  else
    puts "Process is running"
  end
end

find_process

What is the correct way to detect if ruby is running on Windows?

Preferred Option (Updated based on @John's recommendations):

require 'rbconfig'
is_windows = (RbConfig::CONFIG['host_os'] =~ /mswin|mingw|cygwin/)

This could also work, but is less reliable (it won't work with much older versions, and the environment variable can be modified)

is_windows = (ENV['OS'] == 'Windows_NT')

(I can't easily test either on all of the rubies listed, or anything but Windows 7, but I know that both will work for 1.9.x, IronRuby, and JRuby).

How can I get the current operating system name in Elixir?

You can call Erlang os:type to get platform name info:

type() -> {Osfamily, Osname}

Types:

Osfamily = unix | win32
Osname = atom()

Returns the Osfamily and, in some cases, Osname of the current
operating system.

On Unix, Osname will have same value as uname -s returns, but in
lower case. For example, on Solaris 1 and 2, it will be sunos.

In Windows, Osname will be either nt (on Windows NT), or windows
(on Windows 95).

In Elixir you probably have to call

:os.type()

to refer to that function with Osfamily being :unix or :win32.

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