Define scalar data and variables? | Perl Scripting Interiew Questions

The concept of data types is flexible, which is present in Perl. Scalar is a single thing such as a string or a number.
The java concepts such as int, float, string, and double are similar to scalar concept of Perl. Strings and numbers are exchangeable. Scalar variable is nothing but a Perl variable which is used to store scalar data. A dollar sign $ is used by it which is followed by underscores or alphanumeric characters. It is a case sensitive.