From: -j b- <jrb562@...>
Date: 2008-05-07T01:27:10+09:00
Subject: Re: Escaped characters from the command-line

Albert Schlef wrote:
> -j b- wrote:
>> I am working on a parser that allows the user to provide a delimiter as
>> an argument to the script. However, I can not find a way to [elegantly]
>> handle escaped characters (such as \t and \n).
>> A simplified example to illustrate:
>> 
>> # Using
>> s = ARGV.shift
>> puts ['west', 'side', story'].join(s)
>> 
>> $ ./parse.rb '\t'
>> => west\tside\tstory
> 
> It isn't a Ruby issue. It's a shell one. You need to find out how it's 
> possible, in your shell, to specify those special characters. Are you 
> using Linux? Bash?

Yes. Yes. But the idea is that it shouldnt matter.

> 
> So there are at least three ways to do \n in bash.

I know that it possible, from a user standpoint, to input a special 
character in multiple ways. My concern is that I dont want to force that 
restriction on the user. For example, the utility tr will accept '\t' as 
a single character; I find this ultimately more useful than tr '^v[tab]' 
' ' (or any of the above mentioned methods).
If it is a shell issue then I am forced to modify the arguments 
accordingly. However, I'm still looking for a more elegant way then the 
heavy case statement.
I've experimented with a gsub! solution but the way backslashes are 
escaped in regular expressions (particularly when reinserting into a 
string) has me blocked at the moment.

Thanks.

j
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