How can i get process id of UNIX command i am triggering in a Perl script?

Question

I am triggering a UNIX command in Perl script.

I need the process ID of the UNIX command.

For example if i trigger below UNIX command:

# padv         


        

Answer 1

You could use open()

Open returns nonzero on success, the undefined value otherwise. If the open involved a pipe, the return value happens to be the pid of the subprocess.

my $pid = open(my $ph, "-|", "padv -s adv.cfg > adv.out") or die $!;

reading output from $ph file handle instead of output redirect:

my $pid = open(my $ph, "-|", "padv -s adv.cfg") or die $!;

Answer 2

Call fork to create a child process. The process ID of the child process is returned to the parent process. The child process can then call exec to execute the program you want.