From: Matthew Kerwin <lists@...>
Date: 2013-02-22T18:36:28+09:00
Subject: Re: backslash substitution

Mario Ruiz wrote in post #1098396:
> The problem is I cannot put single or doubles since the value is given
> as an argument in command line so the value is taken something like
> this:
>
>     ARGV.each do |x|
>       if !x["folder="].nil? then a=x.gsub("folder=","") end
>     end

Aha!  Now some of what you've said starts to make sense.

I just created this file:

  #test.rb:
  a=nil
  ARGV.each do |x|
    if !x["folder="].nil? then a=x.gsub("folder=","") end
  end
  p a

When I run it in Windows, I get this:

  > ruby test.rb
  nil
  > ruby test.rb folder=a\b\c
  "a\\b\\c"

So you can see that the Windows command prompt has interpreted the
single backslashes as backslashes, and passed them through to Ruby
faithfully.

If I run it in Linux I get this:

  $ ruby test.rb
  nil
  $ ruby test.rb folder=a\b\c
  "abc"
  $ ruby test.rb folder=a\\b\\c
  "a\\b\\c"

So you can see that bash (the command prompt I use) has interpreted the
backslashes as special characters, not entirely unlike the way ruby
would.  However bash (and most *nix shells) give you options like this:

  $ ruby test.rb folder="a\b\c"
  "a\\b\\c"
  $ ruby test.rb folder='a\b\c'
  "a\\b\\c"

The gsub line in Ruby would work just fine, but you also have to tell
your _command prompt_ what you mean when you write a backslash.

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