From: "Aaron D. Gifford" <astounding@...>
Date: 2010-06-05T10:45:28+09:00
Subject: Re: pack('m') and Windows files

Emiliano wrote:
>> The results are that I receive a mail that lacks of the 'end of lines',
>> in which place there are little squares (one per each line, to be fair).
>> Also, filetype is Unix (and not Dos/Windows).
>>
>> I tried previously to substitute \n with \r\n:
>> content = File.read(filename).gsub(/\n/, '\r\n')

To which I responded:
> Make sure you're using double-quotes for "\r\n" and not single-quotes.

I suppose I should have elaborated:

irb(main):001:0> '\n'
=> "\\n"
irb(main):002:0> "\n"
=> "\n"

Notice how encapsulating the backslash within single quotes results in
the string "\\n"?  Backslashes inside single-quoted strings escape the
backslash itself, and also single quotes, but not \r\n CR+LF escape
sequences:

irb(main):001:0> 'This is a backslash: \\'
=> "This is a backslash: \\"
irb(main):002:0> "This is a backslash: \\"
=> "This is a backslash: \\"
irb(main):003:0> 'This is a single-quote: \''
=> "This is a single-quote: '"
irb(main):004:0> 'But other escape sequences do not work: \r\n\t\b'
=> "But other escape sequences do not work: \\r\\n\\t\\b"
irb(main):005:0> "They do within double quotes: \r\n\t\b"
=> "They do within double quotes: \r\n\t\b"

Aaron out.