Ruby to replace contents of file between two markers

Question

Trying to do like Replace content in a file between two markers but the accepted answer doesn't seem to be working:

index.html

<!--start-->Hello world<!--end-->

myscript.rb

def replace(file_path, contents)
    file = File.open(file_path, "r+")
    html = ""

    while(!file.eof?)
        html += file.readline
    end

    file.close()

    return html.gsub(/<!--start-->(.*)<!--end-->/im, contents)
end

thing = ["Foo", "Bar", "Baz"].sample

replace("/path/to/index.html", thing)

After running ruby myscript.rb, index.html remains the same. I'm on Ruby 2.2.0.

Paweł Dawczak · Accepted Answer · 2015-03-18T10:44:32.383

2

Try changing you script as follows:

def replace(file_path, contents)
  content = File.read(file_path)
  new_content = content.gsub(/(<!--start-->)(.*)(<!--end-->)/im, "\\1#{contents}\\3")

  File.open(file_path, "w+") { |file| file.puts new_content }
  new_content
end

thing = ["Foo", "Bar", "Baz"].sample

replace("./my_file", thing)

For working with files - check this great tutorial!

Good luck!

edited Mar 18 '15 at 10:44

answered Mar 18 '15 at 10:02

Paweł Dawczak

9,519
2
24
37

Your method looks a lot better, but unfortunately the index file remains the same. Am I missing something? – Flynt Hamlock Mar 18 '15 at 10:13
@FlyntHamlock - You are absolutely right! I've just updated my answer! (plus some shorter syntax is used). Apologies for confusion! – Paweł Dawczak Mar 18 '15 at 10:23
Awesome - thanks! Is there a way to not remove the `` and `` though? – Flynt Hamlock Mar 18 '15 at 10:25
@FlyntHamlock - Sure you can! Check my answer updated! (also, take a look at this [answer](http://stackoverflow.com/questions/118839/gsub-partial-replace)). Good luck! – Paweł Dawczak Mar 18 '15 at 10:45
Absolutely gorgeous! Thanks again! – Flynt Hamlock Mar 18 '15 at 10:48

Ruby to replace contents of file between two markers

1 Answers1