parent-process.pl

#!/usr/bin/env perl
use strict;
use warnings;
use Linux::Pid qw/getpid getppid/;
my $pid = fork;

if( $pid ){
    warn "Parent: " . getpid();
    warn "Parent's parent: " . getppid();
    exit;
} else{
    #sleep 3;
    warn "Child: " . getpid();
    warn "Parent pid: " . getppid();
}

# Parent: 44361 at - line 8
# Parent's parent: 17147 at - line 9

# Child: 44362 at - line 13
# Parent pid: 44361 at - line 14

### sleep 3をコメントアウト(親が先に死ぬ)
# Parent: 44371 at - line 8
# Parent's parent: 17147 at - line 9

# Child: 44372 at - line 13
# Parent pid: 1 at - line 14