G'day Striker,

I have a different version of top (with different options) so I can't test this. However, looking at this top manpage (which appears to have the same options that you're using), I'd guess you can add a -n iterations to your top command; then put a sleep between the system statements.

So, with a delay of 5 seconds, that would be 36 iterations in 3 minutes:

system "top -p 1758 -b -d5 -n36 | tee -a stats.log";
sleep 180;
system "./top_stats.sh -f stats.log";
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According to that manpage, top should stop running after the set number of iterations, so you won't need a Ctrl-C (or equivalent).

++! Now that you mention it, I remember using -n for running top through 'n' iterations of page refresh. There's also the 'batch mode' for passing output from top to other programs. Here's what my copy of manpage has to say about this:

-b : Batch mode operation
            Starts  top  in 'Batch mode', which could be useful for sending output from top to other programs
            or to a file.  In this mode, top will not accept input and runs until the iterations limit you've
            set with the '-n' command-line option or until killed.

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

my $pid = $$;

my $pid1 = open3(0, \*READ,0,"top -d 2 -b -p $pid ");
            #if \*ERROR is false, STDERR is sent to STDOUT 


while(1){
  my @words = split(/\s+/,<READ>);
  $words[0] ||= 0;
  if($words[0] =~ /$pid/){print "$words[4]  $words[9]\n"}
#print "$words[0]\n";
}

waitpid($pid, 1);
# It is important to waitpid on your child process,  
# otherwise zombies could be created.
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#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;
use IO::Select;

my $pid = $$;

my $pid1 = open3(0, \*READ,\*ERROR,"top -d 1 -b -p $pid ");
#if \*ERROR is false, STDERR is sent to STDOUT

# add more commands here if you want, but make sure the
# filehandles are different. It would be an improvement to use
# IO::Handle for the filehandles


my $sel = new IO::Select();

$sel->add(\*READ);
$sel->add(\*ERROR);

my($error,$answer)=('','');

while(1){

foreach my $h ($sel->can_read){
    my $buf = '';
        if ($h eq \*ERROR){
              sysread(ERROR,$buf,4096);
              if($buf){print "ERROR-> $buf\n"}
}else{

 sysread(READ,$buf,4096);
    if($buf){print "$buf\n"}
   }
  }
}
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I think you want to set timeouts in your subprocesses. Have a look at Timeouts and timers in IPC::Run.

You can use IPC::Run's run method instead of system. and set a timeout.