Question

I’m executing a command inside a perl script and when that command completes, a question is sent to STDOUT requesting a Y or N answer to a question. If no answer is given (i.e. I just end the script) then we have a hung process in the shell waiting for an answer. How can I supply the desired Y answer?

perl v5.8.4
solaris 10

Answer 1

• Simplest:

  Use shell’s ability to redirect “Y” into command’s STDIN:

  `echo "Y" | your_command_expecting_Y`;
  

  or (slightly worse but more flexible).

  `your_command_expecting_Y < /my/file/containing/one/line/with_Y_in_it.txt`; 
  

• More complicated but infinitely more flexible and Perl native:

  Use Expect module

  use Expect;
  # create an Expect object by spawning another process
  my $exp = Expect->spawn($command, @params);
  $exp->send("Y\n");