Can Ruby access output from shell commands as it appears?

Question

My Ruby script is running a shell command and parsing the output from it. However, it seems the command is first executed and output saved in an array. I would like to be able to access the output lines in real time just as they are printed. I've played around with threads, but haven't got it to work. Any suggestions?

Answer 1

You are looking for pipes. Here is an example:

# This example runs the netstat command via a pipe
# and processes the data in Ruby as it come back

pipe = IO.popen("netstat 3")
while (line = pipe.gets)
  print line
  print "and"
end