Edit each line in a file in Ruby

Question

I\'m trying to find a simple way of editing each line in a file, and I\'m having some trouble understanding how to use the File class to do so.

The file

Answer 1

The one of the better solutions(and safest) is to create a temporary file using TempFile, and move it to the original location(using FileUtils) once you are done:

   require 'fileutils'
   require 'tempfile'

    t_file = Tempfile.new('filename_temp.txt')
    File.open("filename.txt", 'r') do |f|
      f.each_line{|line| t_file.puts line.split(",")[0].to_s }
    end
    t_file.close
    FileUtils.mv(t_file.path, "filename.txt")