Question

I have a text file with path name file, and some content string that I want to append to it. I want to do something close to

File.open(file, "a"){|io| io.puts(string)}

but if the original content of the file does not end with an endline character $/, I want to insert one before string. What is the most effective way to do this?

Answer 1

File.open(file, 'r+') do |f|
  unless (last = f.readlines[-1]) && last.end_with?($/)
    f.puts $/
  end

  f.puts string
end