From: Robert Klemme <lists@...>
Date: 2012-03-30T01:11:29+09:00
Subject: Re: copy file into new without dups, eol problem

Jeremy Bopp wrote in post #1053948:
> On 03/29/2012 07:55 AM, Robert Klemme wrote:
>> But what about the dups?  What constitutes a duplicate?  If it is just
>> raw content, you could use "sort -u" (standalone command).
>
> Again from the original example, the records to compare for uniqueness
> are simple lines.  Of course that simplicity belies the issue of line
> endings. ;-)

Ah, I overlooked the call to #uniq.  I think we should be able to fix 
the original with a small insertion:

File.open("newf.txt", "w+") { |file| file.puts
File.readlines("oldf.txt").each(&:chomp!).uniq }

Although from an efficiency point of view another approach would be 
preferable:

File.open "oldf.txt" do |in|
  File.open "newf.txt", "w" do |out|
    last = nil

    in.each_line do |line|
      line.chomp!
      out.puts line unless line == last
      last = line
    end
  end
end

Note that opening "newf.txt" before opening "oldf.txt" will lead to an 
empty file being written in case "oldf.txt" does not exist even though 
an exception is thrown.

> Also, the OP appears to be running on Windows, so "sort -u" is not
> available out of the box.

Right, I'm so used to cygwin that I keep forgetting not everybody has it 
installed. :-)

Cheers

robert

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