I don't know what you mean by a "first a", or a "second a". How do you distinguish between them? 
my $a1 = "a";  # Does it matter "which" 'a' this is?
my $a2 = "a";
my $a4 = "a";
my $b1 = "b";

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Perhaps you mean something else. Could you reformulate your question?

In reply to Re: variables from STDIN by JavaFan
in thread variables from STDIN by stigmatt

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