Incidently, you're getting that error because you are trying to dereference a string (${$config} becomes ${ 'db' }, not the variable $db).

Well, if $config contains the string db, ${$config} is a variable $db. It's not a lexical variable, but a package variable. Still, addressing it with $db works just fine (provided there isn't a lexical $db in the current scope). 

my $config = 'db';
${$config} = 'foo';
print $db, "\n";
__END__
foo

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In reply to Re^2: dynamically creating variables by Anonymous Monk
in thread dynamically creating variables by hesco

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