thufir@dur:~/ruby$
thufir@dur:~/ruby$ ruby tel.rb
/home/thufir/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:51:in `require': cannot load such file -- em/simple_telnet (LoadError)
	from /home/thufir/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:51:in `require'
	from tel.rb:3:in `<main>'
thufir@dur:~/ruby$
thufir@dur:~/ruby$ gem list --local

*** LOCAL GEMS ***

bundler (1.3.5)
bundler-unload (1.0.1)
coderay (1.0.9)
em-simple_telnet (0.0.14)
eventmachine (1.0.3)
method_source (0.8.2)
net-ssh (2.6.8)
net-ssh-telnet (0.0.2)
open4 (1.3.0)
pry (0.9.12.2)
rake (10.1.0)
redcard (1.1.0)
rubygems-bundler (1.2.2)
rubysl-net-telnet (0.0.1)
rvm (1.11.3.8)
slop (3.4.6)
ssh (1.1.0)
thufir@dur:~/ruby$
thufir@dur:~/ruby$ cat tel.rb
#!/usr/bin/env ruby
require 'rubygems'
require 'em/simple_telnet'
require 'yaml'
require 'pry'
require 'pp'

opts = YAML.load_file('params.yml')

EM::P::SimpleTelnet.new(opts) do |host|
  puts host.cmd("ls -la")
end
thufir@dur:~/ruby$