getpw.rb - Prototype of getpw function using io/console#getch function

getpw.rb

#!/usr/bin/env ruby
#
# getpw.rb
# Copyright (c) 2016 Koichi OKADA. All right reserved.
# This script distributed under the MIT license.
#

require 'io/console'

def getpw
  pw = c = ""
  begin
    c = STDIN.getch
    case c
    when /[\x03]/ # C-c
      Process.kill('SIGINT', Process.pid)
    when /[\x1a]/ # C-z
      Process.kill('SIGSTOP', Process.pid)
    when /[\b\x7f]/ # C-h|BS
      if 0 < pw.length
        STDERR.print "\b \b"
        pw.chop!
      end
    when /[\x15]/ # C-u
      STDERR.print "\b \b" * pw.length
      pw = ""
    when /[[:print:]]/
      STDERR.print "*"
      pw += c
    else
      STDERR.print "*"
      pw += c
    end
  end until c =~ /[\r\n]/
  pw
end

if __FILE__ == $0
  STDERR.print "Password: "
  password = getpw.chomp!
  STDERR.puts
  
  print password
end