greeklish_iso843 
A Ruby library that converts Greek text to Greeklish, conforming to the ISO 843 (ELOT 743) standard used by the Greek State.
Installation
As a Gem:
gem install greeklish_iso843
Use
Require the library in your code:
require 'greeklish_iso843'
Then you can use it to convert text:
GreeklishIso843::GreekText.to_greeklish("Μπάμπης") # => "Bampis"
GreeklishIso843::GreekText.to_greeklish("Άγγελος") # => "Angelos"
GreeklishIso843::GreekText.to_greeklish("Ευάγγελος") # => "Evangelos"
GreeklishIso843::GreekText.to_greeklish("ξεσκεπάζω την ψυχοφθόρα σας βδελυγμία") # => "xeskepazo tin psychofthora sas vdelygmia"
Alternatively, you can require the String core extension for more convenience:
require 'greeklish_iso843/core_ext/string'
Then you can use it to convert text:
"Μπάμπης".to_greeklish # => "Bampis"
There's also a command line utility that accepts Greek text from the standard input and prints the corresponding Greeklish text to the standard output:
$ greeklish_iso843
Μπάμπης
^D
Bampis
$
Note: ^D represents the EOF (End Of File) character, emitted with Ctrl-D.
Tests
You can run the tests with rake test or rake test TESTOPTS='-v' for a more
verbose output.
Acknowledgements
This library was initially based on an official, buggy implementation in JavaScript.