Grep for CP932, utf-8 and utf-16 as batch file

grep.bat

@echo off
c:\progra~2\RUBY-2~1.0\bin\ruby -x "%~f0" %*
@goto endofruby
#!C:/PROGRA~2/RUBY-2~1.0/bin/ruby
# coding: utf-8
if ARGV.size < 2
   exit 1
end

def find_pattern(fn, enc, pattern)
  r = ''
  File.open(fn, "rb:#{enc}") do |f|
    r = f.read
  end
  if enc != 'cp932'
    if enc == 'utf-8' && r[0] == "\uFEFF"
      r = r[1..-1]
    end
    r = r.encode('cp932')
  end

  disp = nil
  $cline = 0
  r.each_line do |line|
    $cline += 1
    line.rstrip!
    if line =~ pattern
      puts("File: #{fn}") unless disp
      disp = true
      puts(line)
    end
  end
end

icase = false
recursive = false
loop do
  if ARGV[0] == '-i'
    icase = true
  elsif ARGV[0] == '-r'
    recursive = true
  elsif ARGV[0] == '-n'
    # ignore
  else
    break
  end
  ARGV.shift
end
if icase
  pattern = /#{ARGV[0]}/i
else
  pattern = /#{ARGV[0]}/
end
ARGV.shift

ARGV.each do |fn|
  ['cp932', 'utf-8', 'utf-16'].each do |enc|
    begin
      find_pattern(fn, enc, pattern)
      break
    rescue ArgumentError => e
      if $DBG
        $stderr.puts e.message + ' while reading: ' + fn
        $stderr.puts 'line: ' + $cline.to_s
        $stderr.puts e.backtrace
      end
    rescue Encoding::InvalidByteSequenceError => e
      if $DBG
        $stderr.puts e.message + ' while reading: ' + fn
        $stderr.puts 'line: ' + $cline.to_s
        $stderr.puts e.backtrace
      end
    end
  end
end
__END__
:endofruby