How to call a script interactively from perl

[LetMeAsk]

Hi, i am newbie to perl and coded a small perl program with the below objective as follows:

• 1. Triggering another script(ThirlPartyScript.start) from this perl.
• 2. Directing the output of that script in a file such that only those lines are stored which match a string.
• 3. Mail the file generated at the step 2.

I am able to achieve the above objectives on a test script. But ThirlPartyScript.start after completion expect some inputs and hence user interaction, so when i call this script from my perl code, it never completes as it seems to be waiting for that user interaction to complete. below is the code i am using to execute that third party script:

#Run the command    
open( CMD, "$run_cmd|" ) || die "Not able to run \"$run_cmd\":$!\n"; 
    while( <CMD> ){      # read command's output from the pipe
         # do write to file with what we read back from the proces
        print $fh_cmd_in $_;
      
    }

Can someone let me know how to supply that iterative argument when calling a script from perl so that the called script completes? Thanks

[BrowserUk]

If the script is a purely command line program that takes its inputs from stdin, you can avoid IPC::open3 by feeding the required interactions to via a pipe.

Say the script requires two lines of input, like this one:

#! perl -slw
use strict;

chomp( my $interact1 = <STDIN> );
chomp( my $interact2 = <STDIN> );
print "Got: $interact1 $interact2";

Then you can feed it the required inputs and retrieve its output like this:

C:\test>perl -E"$p = open I, '-|', '( echo fred & echo jim ) | interac
+t.pl'; say for <I>;"
Got: fred  jim

This often will not work for programs that expect passwords.

[zentara]

Here is a simple usage of IPC::Open3 showing how to write to your STDIN.

#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;

#interface to "units" calculator
#my $pid = open3(\*WRITE, \*READ, \*ERROR,"units -t"); #terse output

my $pid = open3(\*WRITE, \*READ, 0 , "units -t");
            #if \*ERROR is set to 0, STDERR is sent to STDOUT 

#chomp(my $prompt = <READ>);
#print "$prompt\n";

foreach ( '100 yards', '1 mile', '1 kilometer', '1 parsec', '1 foobar'
+){  

print WRITE "$_\n meters \n";

chomp(my $answer = <READ>);
print "$_ = $answer meters\n";

}
__END__

[LetMeAsk]

Thanks all for the answers, let me detail the situation again, The third party script after completion (first round) ask a question:

Select Option :

Manually if i supply an "X" then it quits the script but as i am calling this third party script from my perl script i want perl to terminate that script so that the output of the thirdpartyscript can be written to a file(by perl) and so that i can use that file. Sorry if you replied to the exact scenario. Thanks

[zentara]

You have me confused. How can you terminate the script in a way that allows it to output to a file? You need to describe in exact detail how this third party script runs. Maybe you are looking to put the process in the background, i.e. a background process?

[Illuminatus]

You want Open3. This assumes you know what you need to write to the third-party script to get it to exit gracefully

fnord