Sample install script:

#!/usr/bin/perl

my %questions = (
    'Path for package: ' => <<EOH,

So we are poing to install The Best All-Purpose Compiler ever.
It groks perl, java, c#, haskell, forth and lisp and many more
all at the same time. Big deal.

EOH
    'do you want Visual Basic support? ' => <<EOH,

The next abomination is optional. PLEASE think again if you are
inclined to install support for that cruft.

EOH
    'What is your nick? ' => <<EOH,

We want some sensitive information from you to harrass you on
every IRC channel in which you talk bad of our product. Yes,
we monitor them all.

EOH
);

for (keys %questions) {
    print $questions{$_};
    sleep 1;
    print;
    chop ($foo = <STDIN>);
    sleep 1;
    print "you said: '$foo', good. We'll come back to that.\n";
}
print "Thank you for using The Great Foo.\n";
[download]

expect script to deal with that install script:

#!/usr/bin/perl

use Expect;

my %answers = (
    'Path for package: ' => '/foo/bar/quux',
    'do you want Visual Basic support? ' => 'NO!',
    'What is your nick? ' => 'shmem',
    'Thank you' => '',
);

my $exp = Expect->new();
$exp->spawn( 'perl', 'install.pl') or die;
my $prompts = join('|', map {qr{\Q$_\E} } keys %answers);

$exp->expect(120,
    -re => $prompts,
    sub {
        my $exp     = shift;
        my $matched = $exp->match;
        my $answer  = delete $answers{$matched};
        $exp->send( $answer."\n");
        $exp->exp_continue if keys %answers;
    }   
);  
print "All done.\n";
[download]

Output:

So we are poing to install The Best All-Purpose Compiler ever.
It groks perl, java, c#, haskell, forth and lisp and many more
all at the same time. Big deal.

Path for package: /foo/bar/quux
you said: '/foo/bar/quux', good. We'll come back to that.

We want some sensitive information from you to harrass you on
every IRC channel in which you talk bad of our product. Yes,
we monitor them all.

What is your nick? shmem
you said: 'shmem', good. We'll come back to that.

The next abomination is optional. PLEASE think again if you are
inclined to install support for that cruft.

do you want Visual Basic support? NO!
you said: 'NO!', good. We'll come back to that.
Thank you for using The Great Foo.
done.
[download]

That's how it works, basically. Of course, you'll have to tweak your regexes well.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

Dear shmem,

Thanks a lot for the response.
You were instrumental in understanding me the working

You saved my day!!! :)

Could you please put some light on how did you managed to get only a single instance of the answers in your run that we are sending to the installation script?

I am getting either 3 (when ran your script as is) or none (when I have: $expObj->raw_pty(1)).

Sample output:

bash-3.00# ./installPerl.pl

So we are poing to install The Best All-Purpose Compiler ever.
It groks perl, java, c#, haskell, forth and lisp and many more
all at the same time. Big deal.
[download]

# ========= 3 instances in OUTPUT BELOW =========

Path for package: /foo/bar/quux
/foo/bar/quux
/foo/bar/quux
you said: '/foo/bar/quux', good. We'll come back to that.

We want some sensitive information from you to harrass you on
every IRC channel in which you talk bad of our product. Yes,
we monitor them all.

What is your nick? shmem
shmem
shmem
you said: 'shmem', good. We'll come back to that.

The next abomination is optional. PLEASE think again if you are
inclined to install support for that cruft.

do you want Visual Basic support? NO!
NO!
NO!
you said: 'NO!', good. We'll come back to that.
Thank you for using The Great Foo.
All done.
bash-3.00#
[download]

Code showing no instances of the answers:
modified this single line in install.pl:

print "you said: '$foo', good. We'll come back to that.\n";
[download]

to include a newline character as:


print "\nyou said: '$foo', good. We'll come back to that.\n";
[download]

Sample run:
----------------------------------------

bash-3.00# ./installPL.pl

So we are poing to install The Best All-Purpose Compiler ever.
It groks perl, java, c#, haskell, forth and lisp and many more
all at the same time. Big deal.
[download]

# ========= NO instances in OUTPUT BELOW =========

Path for package:
you said: '/foo/bar/quux', good. We'll come back to that.

We want some sensitive information from you to harrass you on
every IRC channel in which you talk bad of our product. Yes,
we monitor them all.

What is your nick?
you said: 'shmem', good. We'll come back to that.

The next abomination is optional. PLEASE think again if you are
inclined to install support for that cruft.

do you want Visual Basic support?
you said: 'NO!', good. We'll come back to that.
Thank you for using The Great Foo.
All done.
bash-3.00#
[download]

Regards,
~DeepBlue