Ruby File Text Trimming Script

I want to share a ruby script for how to trim a file text above a certain line number or any condition

require 'fileutils'

class File_Text_Trimmer
    def self.trim_text(line_number)
        open('some.txt', 'r') do |f|
          open('some.txt.tmp', 'w') do |f2|
            f.each_line do |line|
               f2.write(line) unless $. < line_number
                      # this is condition    
                      #  $. < line_number    
            end
          end
        end
        FileUtils.mv 'some.txt.tmp', 'somechanged.txt'
        # to save changes in same file or to overwrite
        # FileUtils.mv 'some.txt.tmp', 'some.txt'
    end
end

In, above you can send the line_number as an argument to this method

To run on Windows 10, first install Ruby from their official site. Mostly it will be installed in C:\Ruby[version]-x[32|64].

If you have saved above script at location

D:\Ruby-Script\File_Text_Trimmer.rb

Then you can call this script like this

ruby -r "D:\Ruby-Script\File_Text_Trimmer.rb" -e "File_Text_Trimmer.trim_text 5"

One thing more some.txt file should be in same folder from where you are running above command or you can give its full absolute path.

To do, make the filename also argument base.

Thats it!