a.pl
[lahotip@vnc10 ~]$ cat a.pl
#! /usr/bin/local/perl

system "b.pl &";
system "b.pl &";
system "b.pl &";
system "b.pl &";
system "b.pl &";

------------------------------

b.pl
[lahotip@vnc10 ~]$ cat b.pl
#!/usr/local/bin/perl -w

print "hi from b.pl" . "\n";
sleep (60);

-------------------------------

Launched as -

> ssh <hostname> a.pl
*does not exit and waits for all the 5 b.pl instances to finish, whereas a.pl has exited*