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POpassing arguaments to a system call in Rails, but not plain ruby program
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  1. POpassing arguaments to a system call in Rails, but not plain ruby program
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    copied!<p>Ubuntu 12.04</p> <p>Sinatra 1.3.3</p> <p>Why does passing an argument to a ruby system call (%x[] or ``) give me a 'not found' error in my sinatra app? The same code works fine in a normal ruby script running from the same directory.</p> <p>I have a file test.rb like this</p> <pre><code>output = %x["ls"] p output </code></pre> <p>When I run it with "ruby test.rb" I get the contents of the current directory in the console, as expected.</p> <p>If I modify the program to give an argument to the system call like so:</p> <pre><code>output = %x["ls sub_dir/"] p output </code></pre> <p>I get the contents of sub_dir, which sits in the current directory, as expected.</p> <p>So far so good.</p> <p>Now if I make a Sintra app with a post method:</p> <pre><code>require 'rubygems' require 'bundler/setup' require 'sinatra' post "/" do output = x["ls"] return output end </code></pre> <p>The response to a Post call to "/" returns the contents of the current directory, which includes 'sub_dir', as expected.</p> <p>If I try to add the argument to the system call to the sinatra app like so:</p> <pre><code>require 'rubygems' require 'bundler/setup' require 'sinatra' post "/" do output = x["ls sub_dir/"] return output end </code></pre> <p>the response is nil and there is an error in the console:</p> <blockquote> <p>sh: 1: ls sub_dir/: not found</p> </blockquote> <p>Why does adding a parameter to a system call in my sinatra app cause it to crash, when the same code called from a plain ruby script, run from the same location works perfectly.</p> <p>By the way, the 'ls' example shown here is not the command I really need to run, so please don't explain a different way to get this information. I have an executable file that takes a file name as a parameter that I need to run, which behaves exactly the same way.</p> <p>Thanks in advance!</p>
 

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