Summary

Perl supports user -definable functions, called subroutines or subs, that behave just like the built-in functions: They can take arguments, do work, and then return values to the caller if necessary. Perl subroutines can call other subroutines and even themselves . Perl also allows you to declare variables private to a subroutine (or any block of code) and create self-contained pieces of code that can then be reused.