We’ll describe below some of the most frequently built-in Perl miscellaneous functions. Follow the available links to get more info about these functions.
| defined | it tests whether a value, variable or function is defined; using it on an entire array reports if the array has ever been allocated |
| scalar | enables you to evaluate an expression in a scalar context and returns the value of that expression |
| undef | it removes a variable or function definition; if you use it for an entire array, this function will clear the array and free up the system memory allocated for it |