As stated by others the 1 shows that the subroutine does its job and return even when return was not stated explicitly, for all it worth, it should also be noted that subroutine should also be called with parentheses like this:

 foo();
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even when no parameter is been passed.
Reason ( Imagine this: calling the subroutine before it's decleared):

  foo;  ## Oops
sub foo {
print "hello";
}
print "\n";
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but with

 
  foo(); # it works
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