Ruby run shell command in a specific directory

I know how to run a shell command in Ruby like:

%x[#{cmd}]

But, how do I specify a directory to run this command?

Is there a similar way of shelling out, similar to subprocess.Popen in Python:

subprocess.Popen(r'c:\mytool\tool.exe', cwd=r'd:\test\local')

Thanks!

Solution 1:

You can use the block-version of Dir.chdir. Inside the block you are in the requested directory, after the Block you are still in the previous directory:

Dir.chdir('mydir'){
  %x[#{cmd}]
}

Solution 2:

Ruby 1.9.3 (blocking call):

require 'open3'
Open3.popen3("pwd", :chdir=>"/") {|i,o,e,t|
  p o.read.chomp #=> "/"
}

Dir.pwd #=> "/home/abe"

Solution 3:

also, taking the shell route

%x[cd #{dir} && #{cmd}]

Solution 4:

The closest I see to backtricks with safe changing dir is capture2:

require 'open3'
output, status = Open3.capture2('pwd', :chdir=>"/tmp")

You can see other useful Open3 methods in ruby docs. One drawback is that jruby support for open3 is rather broken.