Perl's Unix heritage shows in many of its built-in features, which are borrowed directly from Unix tools such as shells, or relate specifically to the management of various Unix files. In this part of the lesson, then, we'll look at the features in Perl useful on Unix systems, including
Working with environment variables
Using the system function to run other programs
Running other programs and capturing their output with backquotes
Creating and managing new processes with fork, wait, and exec
Some functions for managing Unix user and group information
Note that with the exception of processes, many of these features might also be available in versions of Perl for other systems, with different or more limited behavior. So, even ...