$ ./6.fork.pl
relevant processes with pstree command:
6.fork.pl,6780 -w ./6.fork.pl
  |-6.fork.pl,6781 -w ./6.fork.pl
  |   `-sh,6783 -c ping www.google.com >5.fork.txt
  `-pstree,6782 -Apal 6780
6781 terminated
PING www.google.com(sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004)) 56 data bytes
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=1 ttl=54 time=30.6 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=3 ttl=54 time=147 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=4 ttl=54 time=16.3 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=5 ttl=54 time=137 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=6 ttl=54 time=123 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=7 ttl=54 time=20.5 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=8 ttl=54 time=20.7 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=9 ttl=54 time=20.3 ms
64 bytes from sea15s11-in-x04.1e100.net (2607:f8b0:400a:808::2004): icmp_seq=10 ttl=54 time=24.2 ms
10 seconds elapsed instead of a year