BOM無しUTF-8のファイルをBOM付きで一括で保存し直す ref: http://qiita.com/snaka/items/2e2ec9961834f6629d69

bomcheck.rb

dirs = ["./trunk/unity/Assets/Source/**/*.cs", "./trunk/unity/Assets/Editor/**/*.cs"]

dirs.each do |dir|
  Dir.glob(dir).each  do |f|
    next unless File.file?(f)
    hoge = open(f)
    hoge.binmode
    begin
      if hoge.read(3).unpack("h*")[0] != "febbfb"
        puts f.to_s #+ " is *NOT* BOM file"
      end
    rescue
    end
  end
end

file1.txt

$ for f in $(ruby bomcheck.rb); do vim -c "set fenc=utf-8 bomb" -c "x" $f; done