Beginning Perl

Chapter 17

Plays Well with Others

WHAT YOU WILL LEARN IN THIS CHAPTER:

• Reading user input from STDIN and handling command-line arguments
• Reading and writing from/to other programs and understanding STDOUT and STDERR

WROX.COM CODE DOWNLOAD FOR THIS CHAPTER

You can find the wrox.com code downloads for this chapter at http://www.wrox.com/remtitle.cgi?isbn=1118013847 on the Download Code tab. The code for this chapter is divided into the following major examples:

• listing_17_1_directions.pl
• example_17_1_poets.pl
• example_17_2_capture.pl
• listing_17_2_wc.pl

Up to this point, you’ve learned quite a bit about how Perl programs work, but they’ve largely been standalone programs. You haven’t done much work reading information from the command line or reading from or writing to other programs and you haven’t deeply investigated how output is handled. This chapter, although not the last, “wraps up” your beginning Perl knowledge and puts you on the path to becoming a well-rounded Perl developer.

THE COMMAND LINE

If your previous experience with computers has been limited to graphical user interfaces (GUIs), you may have trouble understanding the full power of the command line. Although a pretty graphic interface can make it easy to see how things are organized, it can make some things harder. For example, moving a file to a different directory and renaming it are two steps requiring a few clicks. From the command line, to move foo.txt to backups/mydata.txt, you can do this in with command: ...