G'day vinoth.ree,

All of these issues are explained in perlop - Range Operators. Quickly pointing you to the relevant parts:

• "Binary ".." is the range operator, which is really two different operators depending on the context. In list context, it returns ..." (doco mirrors your expectations)
• Two paragraphs down: "In scalar context, ".." returns ..." (doco explains how a false value, i.e. your 'empty string', is returned)
• Two more paragraphs down: "If either operand of scalar ".." is a constant expression, that operand is considered true if it is equal (==) to the current input line number (the $. variable)." (explanation for your "uninitialized value $." warning)