From: Robert Klemme <shortcutter@...>
Date: 2010-11-28T21:00:15+09:00
Subject: Re: How to use Ruby like shell script?

On 28.11.2010 09:50, Yu-Hsuan Lai wrote:

> OH, sorry for my poor English.
> Infact what I want to do is not "use ruby like shell script" but "use shell
> in ruby".
> For instant, I wonder if I can use "ls | grep" or "tar -xvf | grep" to get a
> file list and store it in a ruby array, and handle them with io#gets.

You do not need to call "ls" from Ruby scripts because there are Dir[], 
Dir.glob and File.stat.  In fact, this is much more efficient and robust 
(semantics of "ls" changes dramatically between operating systems).

For the case with "tar" you can do

# 1.9
IO.popen ["tar", "xvf", file_name] do |io|
   io.each do |line|
     puts "found #{line}" if /\.rb$/ =~ line
   end
end

# 1.8
IO.popen "tar xvf #{file_name}" do |io|
   io.each do |line|
     puts "found #{line}" if /\.rb$/ =~ line
   end
end

You can even use grep:

io.grep /\.rb$/ do |match|
   puts "found: #{match}"
end

> I don't know what "back ticks" are.

output=`ls -l`

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/