Your mytest routine will run concurrently, but you have a race condition. You should pass the value of $j into the thread at thread creation time instead of accessing a global variable. As your threads run, there is a chance that two threads will try to use the same value in $j to move a file.
Aren't Perl variables supposed to be non-shared by default?

In reply to Re^2: Did I create a concurrent program? by JavaFan
in thread Did I create a concurrent program? by jweden1

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