This page contains automated test results for code from O'Reilly's Ruby Cookbook. If this code looks interesting or useful, you might want to buy the whole book.
Driving an External Process with popen | ||
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Code | Expected | Actual |
%x{whoami} |
"leonardr\n" | "leonardr\n" |
puts %x{ls -a empty_dir} |
. .. |
|
IO.popen('tail -3', 'r+') do |pipe| 1.upto(100) { |i| pipe << "This is line #{i}.\n" } pipe.close_write puts pipe.read end |
This is line 98. This is line 99. This is line 100. |
This is line 98. This is line 99. This is line 100. |
IO.popen('-', 'r+') do |child_filehandle| if child_filehandle $stderr.puts "I am the parent: #{child_filehandle.inspect}" child_filehandle.puts '404' child_filehandle.close_write puts "My child says the square root of 404 is #{child_filehandle.read}" else $stderr.puts "I am the child: #{child_filehandle.inspect}" number = $stdin.readline.strip.to_i $stdout.puts Math.sqrt(number) end end |
I am the child: nil I am the parent: #<IO:0xb7d25b9c> My child says the square root of 404 is 20.0997512422418 |
My child says the square root of 404 is |