Remove lines from file on regex match

remove_lines_from_file.md

How to remove lines from file on regex match in ruby

# remove_comment_lines_from_haml_file.rb
require 'fileutils'

open('file.html.haml', 'r') do |f|
  open('file.html.haml.tmp', 'w') do |f2|
    f.each_line do |line|
       f2.write(line) unless line =~ /^\s+\/.*$/ # regex for comments in haml template
    end
  end
end
FileUtils.mv 'file.haml.html.tmp', 'file.html.haml'
puts 'success'