From: Robert Dober <robert.dober@...>
Date: 2009-08-19T01:42:24+09:00
Subject: Re: fromdos dos2unix in ruby

On Tue, Aug 18, 2009 at 5:50 PM, Rob
Biedenharn<Rob@agileconsultingllc.com> wrote:
>
> On Aug 18, 2009, at 11:21 AM, Robert Klemme wrote:
>
>> 2009/8/18 krzysztof cierpisz <ciapecki@gmail.com>:
>>>>
>>>> Well, you would read from the input file, replace the dos/windows line
>>>> endings with unix ones and write to the output file.
>>>>
>>>
>>> I tried with following dos2unix.rb script
>>>
>>> ###### dos2unix.rb ######################
>>> out = File.open(ARGV[1],"w")
>>>
>>> File.open(ARGV[0]).each {|line|
>>>  out << line.gsub!(/\r$/,'')
>
> You open the file with the default mode of 'r' here so the File class is
> going to do the line-ending conversion for you. Then you use String#gsub!
> which returns nil when no changes are made. You are never going to get
> output this way.
>
>>> }
>>>
>>> out.close
>>> #########################################
>>>
>>> this:
>>> ruby dos2unix.rb u8nl_utf8_tab.dos.txt d
>>>
>>> works fine on Linux (d with length 408 bytes) but not on Windows, on
>>> Windows d is a file with 0 bytes
>>
>> You are not closing the File object properly so your output might
>> never get flushed to disk...
>>
>> Cheers
>>
>> robert
>>
>> --
>> remember.guy do |as, often| as.you_can - without end
>> http://blog.rubybestpractices.com/
>
>
> Try something like this:
>
> buffer = ''
> File.open(ARGV[1], 'wb') do |out|     # open for writing binary
>  File.open(ARGV[0], 'rb') do |in|    # open for reading binary
>    while in.read(1024, buffer)       # read upto 1024 bytes into buffer
>      out.write buffer.gsub(/\r\n/, "\n")  # change ending and write out
fancy little bug here Rob, do you spot it?











What if \r is the 1024th char?
This will happen, one day ;)
Unless the file is hugh I would try
File.open....
   File.open ...
      out.print in.read.gsub( /\r\n/, /\n/ )
   end
end

If performance can be an issue we could use File#each with 10.chr as a seperator

     in.each 10.chr do | line |
         out.print line.sub( /\r\n\z/, 10.chr )
     end

HTH
Robert
-- 
module Kernel
  alias_method :ë, :lambda
end