$ perl 968307.pl
hello 1  from main
hello 2  from main
hello 3  from main
hello 4  from main
hello 5  from main
hello 6  from main
hello 7  from main
hello 8  from main
hello 9  from main
hello 10  from main
hello 1 from thread 1
hello 1 from thread 2
hello 1 from thread 3
hello 1 from thread 4
hello 1 from thread 5
hello 1 from thread 6
hello 1 from thread 7
hello 1 from thread 8
hello 1 from thread 9
all done, press the Enter key to exit
hello 1 from thread 10
hello 2 from thread 1
hello 2 from thread 2
hello 2 from thread 3
hello 2 from thread 4
hello 2 from thread 5
hello 2 from thread 6
hello 2 from thread 7