This chapter and the next explore interacting with Perl through the command line. This is a broader subject than it might at first appear, since it covers everything from command-line processing to properties of shells and terminal programming. A desktop icon can be configured to trigger a command too, so even in a graphical world command-line processing can still be relevant. Perl was partly inspired by Unix commands like
awk and so inherits a lot of shell-like sensibilities and syntax. Not surprisingly, therefore, Perl turns out to be quite good at command-line processing.
We begin by looking at how we read command-line options into our Perl programs, starting with the special array