Updated:

From perldoc -f system:

               You can check all the failure possibilities by inspecti
+ng $?
               like this:

                   if ($? == -1) {
                       print "failed to execute: $!\n";
                   }
                   elsif ($? & 127) {
                       printf "child died with signal %d, %s coredump\
+n",
                           ($? & 127),  ($? & 128) ? ’with’ : ’without
+’;
                   }
                   else {
                       printf "child exited with value %d\n", $? >> 8;
                   }
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I see you are not using the return value (system) nor the output (backtick). I recommend you to use system and allways check the return value of the process.

Thank you for your input!

If you do something like:

`$swbt_dms $item > $log/$key`;
$key = ...read file $log/$key...
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Then you could simply do:

$key = `$swbt_dms $item`;
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Otherwise, it's a waste to use `` when you discard the return value::

$key = system("$swbt_dms $item");
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In Windows, you could also use Win32::Process and call $process->Wait().

exec is not appropriate since it doesn't return.

fork+exec, IPC::Open2, IPC::Open3, system 1, (Win32) and Win32::Process without $process->Wait() (Win32) are not appropriate since they create a process that runs in parallel.

I need to capture the output from the Expect script so that it can be evaluated and this is why the backticks were used, but if the ouput from the Expect script ($swbt_dms) can be captured without the use of backticks this would be great. The arguement ($item) provided to the Expect script is either Datakit or IP info. So with all of this said, what would be the most appropriate method of capturing into a file (has to be into a file) the output from the Expect script so that it can be evaluated? Hay, thank you for taking time to help me with elevating my Perl knowledge.

I'm not sure what you mean by evaluate. If you mean executed as perl code, how about eval ``:

$ perl -e 'eval `echo print 1+3`';
4
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Otherwise, system will do just fine:

$ perl -e 'system("echo bla > file");'
$ cat file
bla
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OK, can you please explain your comment? I am not being test or anything like that, I just want to know if something can be done better or more efficent... then lets do it! Thanks, Terry.

I'm studying to the code, trying to work out what is going on. My first comment was just a reaction to trying to find where the subroutine arguments were going and how used. etc.

I'm not sure about the performance differences between backticks and the system call. I do know you don't want exec because it essentially replaces the script process with the new process of the exec call. There would be no way for your next line to be reached.

Are you benchmarking the spawning of processes here? What's up? -ben (perlcapt)

UPDATE:

I came across this Spawing other programs in Perl which might help. The big difference it useability between backticks and system() is what they return. Backticks return the stdout of the spawned process, and system() returns the exit code. -ben

  $key = `$sxwbt_dms $item`
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open(SWBT, "$swbt_dms $item |")
while(<SWBT>) {
   process_line($_);
}
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