From: Brian Candler <b.candler@...>
Date: 2010-09-28T02:57:30+09:00
Subject: Re: passing single backslash character as commang line argument

Kashyap Ivaturi wrote:0
> Please let me know how to get the backslash character in the string in
> the test2.rb program.

That depends.

If you insist on invoking system with a single string argument, it gets 
passed to the shell to execute - something like /bin/sh -c "the string".

This means the shell breaks it into words, and you have to deal with the 
shell's rules for handling quoting and backslashes:

irb(main):004:0> str = "\\"   # one backslash
=> "\\"
irb(main):005:0> system("echo \"#{str}\"")
sh: Syntax error: Unterminated quoted string
=> false
irb(main):006:0> str = "\\\\" # two backslahses
=> "\\\\"
irb(main):007:0> system("echo \"#{str}\"")
\
=> true

If instead you use the multi-argument form of system, then you don't get 
a shell - Ruby invokes the program directly with the arguments given. 
This means you don't need to worry about backslashes, or even quoting.

That is:

system("/usr/bin/ruby", test2AbsolutePath, text)

will pass those three args, and you don't need to quote the text even if 
it contains spaces, backslashes or whatever. I strongly recommend you go 
this way.

To find the full path to the ruby interpreter, have a look at the 
rbconfig library.
-- 
Posted via http://www.ruby-forum.com/.