You're asking for symbolic references, huh? At least, I think you are. Well: don't do it, unless you know really well what you're doing — and basically, if you have to ask how to do it, I dare to bet that you don't. Making a name based on a user's input is always very dangerous. You never know whether he'll input the name of a variable you've used yourself in your program.

See dominus' classic 3 articles on his website, for more arguments against it:

1. Why it's stupid to `use a variable as a variable name'
2. A More Direct Explanation of the Problem
3. What if I'm Really Careful?

In general: don't do it. Use a hash. Like this:

my %v;   # my hash for user variables
$v{Sam}++; 
# or:
my $name = 'Sam';
$v{$name}++;
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Oh, and if you really want to do it, try $$name or ${$name}, which both do the same thing, and only work on global (= package) variables — and only with no strict 'refs'. Just to show you it can be done... ;-)

If all you want is to work on predefined variables with no input from the user/outside world, try hard references instead.

my $var = \$sam;
$$var++;  # increments $sam
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Yes, the syntax is exactly the same. That's one reason why coding without strict 'refs' in place, is a rather bad idea.