#!/usr/bin/perl print "Please enter a number: "; $n = <STDIN>; print "number: $n";STDIN denotes Standard Input, which is usually the terminal from which the program was invoked.
During the execution of a Perl program, each time the term <STDIN> is encountered, the program stops and waits for the user to enter some characters followed by a newline (Return).
The entered strings will then become the value of <STDIN>.
Note: These rules hold if <STDIN> was written in a place where a scalar value was expected, e.g. if <STDIN> is assigned to a scalar variable.