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Reviewer Greg Smith here dissects a book aimed at programmers who want to add Perl to their stable of languages, but also useful to the Perl connoisseur. If your interest in Perl is more than casual -- especially if you're seeking practical code examples more substantial then in more introductory texts -- The Perl Black Book may be for you. (Read more.)

The Perl Black Book author Steven Holzner pages 1283 publisher Coriolis rating 7/10 reviewer Greg Smith ISBN 1-57610-465-6 summary Perl introduction and reference guide with lots of example code, targeted at those already familiar with another programming language.

The Scenario You already know C or BASIC or some other programming language, but there's some work you need to finish that none of these languages are the right tool for. Perhaps you want to create CGI programs. The Perl Black Book is an excellent choice to fill that need. It's a non-nonsense title that's focused on working example code in a form that will be familiar to those stepping from another programming language into Perl. What's Bad While the book is large, the scope of material it attempts to cover is considerably larger. Coriolis labels the book as intended for intermediate to advanced materials, and there's a minimum of introduction to general programming concepts. Non-programmers trying to learn Perl as their first language would be better served starting with a more introductory title and coming back to this book later. And while there are examples of things like object-oriented Perl and CGI, none of that material goes deep enough to really satisfy a serious student of those topics.

The most annoying thing about this Coriolis release is the introduction to most sections. Holzner spins these little stories about a Novice Programmer, his Big Boss, a Programming Correctness Czar, and other random characters to suggest why you'd need to know about a topic. I question the necessity of these motivational interludes, as they take up space, waste my time reading them, and offer very little in return. The kind of person I'd expect to be reading this book doesn't need a little story suggesting why you'd want to be able to format text when you print it; that this is a useful thing to learn is pretty obvious.

What's Good The Perl Black Book does an excellent job with the kinds of things intermediate programmers in the language are interested in. It's become the first place I turn to when looking for a snippet of Perl code to incorporate into a project. An example of why I like this book should illustrate why that is. I recently found myself writing a program that needed to ping a host and take some corrective action if that ping was unsuccessful. I would expect this is a straightforward request, and looked up "ping" in the index of O'Reilly's Programming Perl. This led to an example using the pingecho library call, which I typed in and found utterly unsuccessful at the task I was trying to accomplish. Looking up the same topic in the Perl Black Book, I found a section about twice as large on the subject. Holzner's example program worked just as I was expecting, and I went back to the rest of the application design without needing to focus for very long on the implementation details of this small piece. I've never liked the code in Programming Perl because the samples are all so terse. The Perl Black Book does a much better job in my view of providing programs long enough to demonstrate the appropriate Perl syntax for filling common needs. So What's In It For Me? Since so much Perl programming is done in the context of a CGI script, many chapters of this book are devoted to that topic. The majority of the material revolves around using Lincoln Stein's CGI.pm library. Much of this mimics Stein's own book, Official Guide to Programming with CGI.pm, but instead of the reference-guide approach, there's more of an emphasis on practical solutions for regularly recurring requests. Example code shows how to create Web counters, guest books, e-mailers, chat, shopping carts and other popular items. A single chapter also introduces usage of the older cgi-lib.pl to create basic HTML pages, but the main focus is definitely CGI.pm, using all of its abstraction. While the CGI section is substantial, considerably more so than the average Perl programming book, there are a number of areas that will need supplementation before you'd want to create a production system. The discussion of the taint mechanism for security is a bit weak, and the basic information about cookies and hidden fields doesn't really give an impression of how to build a larger-scale Web application and properly save state along the way. That is, to be fair, outside of what I'd expect a Perl book cover, and it's only because most of the other material so is helpful that these weaker areas stick out.

The Perl Black Book provides plenty of the kind of examples I'm looking for when writing a Perl program, and it's large and comprehensive enough to cover most areas in sufficient depth. The real question is whether it meshes well with your approach to the language. Holzner is obviously aiming this title at someone who is learning Perl as their second, third, or nth programming language. The samples avoid relying on Perl-specific idioms in most cases. Personally, I find this approach refreshing, as programs I write in Perl frequently end up getting ported to another language later, or co-opted by another programmer who isn't as familiar with the language. So for me, writing Perl that embraces too heavily Perl's language specific features leads to portability and maintenance problems later. For example, when I read through Randal Schwartz's Learning Perl, by page 11 he's already using regular expressions to match strings. I find myself wanting to use a more traditional substring/comparison operation in that context instead, because I know that code will port to any other language easily, and any competent programmer will understand what I'm doing regardless of their familiarity with Perl. Holzner understands that mindset, and writes his prose and programs accordingly; witness the following tip from P291:

"The line ++@_[0]; is a cute example of why nonprogrammers think Perl is obscure. Try showing that line to your grandmother and explaining that you write stuff like that for a living."

If you look at the example above and think that's a nice way to use Perl, by all means stick to the traditional books on the topic from Schwartz, Larry Wall and Tom Christiansen. But if you think that line is unnecessarily cryptic, I think you'll be impressed with how little material like that is inside Holzner's Perl Black Book. It doesn't try to embrace "The Perl Way," but it is a quite useful resource when you're on a short deadline to deliver a working program and don't have time to absorb too much of the language to do it. I'm buying a second copy for the office this week because mine keeps walking away, and there's no greater recommendation for a computer title than noting that copies of the book disappear regularly.

Purchase this book at ThinkGeek.

Table of Contents

1. Essential Perl
2. Scalar Variables and Lists
3. Arrays and Hashes
4. Operators and Precedence
5. Conditional Statements and Loops
6. Regular Expressions
7. Subroutines
8. Formats and String Handling
9. References
10. Predefined Variables
11. Built-In Functions: Data Processing
12. Built-In Functions: I/O
13. Built-In Functions: File Handling
14. Built-In Functions: Interprocess Communication
15. Standard Modules
16. Perl/Tk--Windows, Buttons, and More
17. Data Structures and Databases
18. Debugging and Style Guide
19. Creating Packages and Modules
20. Creating Classes and Objects
21. Object-Oriented Programming
22. Internet and Socket Programming
23. CGI Programming: CGI.pm
24. CGI Programming With Other Popular Package
25. CGI: Creating Web Counters, Guest Books, Emailers, and Secure Scripts
26. CGI: Creating Multiuser Chat, Server Push, Cookies, and Games
27. CGI: Creating Shopping Carts, Databases, Site Searches, and File Uploads
28. Handling the Web in Code

Thanks to Greg Smith for his review of O'Reilly and Associates' Unix Backup and Recovery. Not suprisingly, the book is complete coverage of Unix backup and recovery. Huh. Truth in advertising. Whodathunkit? Unix Backup & Recovery author W. Curtis Preston pages 709 publisher O'Reilly, 1999 rating 10/10 reviewer Greg Smith ISBN 1-56592-642-0 summary Complete coverage of Unix backup and recovery, just like the title says

Cover Image

The Scenario You're a system administrator suddenly tasked with handling the backup of all your employer's mission-critical data. Or maybe you've been handed a tape of questionable origin with the instructions "I need all the files off of this." Perhaps you're working on your company's disaster-recovery plan and are looking for advice about how to restore all the computers to operation in the event of catastrophe. Unix Backup & Recovery is a comprehensive volume designed to help with all of these tasks and many others. What's Bad While the organization of topics is clear, the sheer scope of the book prevents easy digestion of the material by the casual reader. Those expecting to read a chapter or two at random may find some of the concepts hard to follow unless they first read the full 65 pages of introductory material. Also, I would have liked to see a clearer discussion of the differences in procedure and general philosophy between a typical small shop (where tapes are organized based on the day the backup was made) and the kind of unique-volume labeling that tends to accompany larger systems or commercial backup products. Since a lot of Unix systems are being managed lately by people whose background is in smaller systems, making this kind of transition is a very important topic.

One part of the book's design may be good or bad depending on how you intend to read it. Areas deemed especially time-sensitive, like what features are included with which commercial backup system, are not addressed in the book. Instead, readers are referred to the author's backupcentral.com site for the latest information. While assuming that any Unix administrator has Internet access is probably not unreasonable, I found myself reading a lot of this book during spare moments while waiting for routine chores to complete. It was not helpful that I needed to access the Web site in order to follow the chapter I was reading while I waited for my car's oil to be changed.

What's Good With many years' worth of practical experience, several specialist contributors, and dozens of technical reviewers, this book leaves few stones unturned. No matter how experienced you are at managing backups, you could probably learn at least a few tricks from Curtis Preston and his crew. Normally discussions about backups are relegated to, at best, a single chapter in a Unix administration book. Unix Backup & Recovery is the first title I've ever seen that covers this territory in full detail. In fact, even if you aren't specifically a Unix administrator, the discussion of topics like the most common causes of system failure and how to pitch a more reliable backup scheme to management are very cross-platform. They're worth reading no matter what type of computer system you rely upon. So What's In It For Me? The first two chapters of the book provide a real-world approach to backups that include often-unaddressed topics like the availability of the backup hardware in the future, dealing with off-site storage, and exactly how high the cost of poor backups can be. With that basis, the native Unix utilities (dump, cpio, and tar) are evaluated. One particularly good part of that coverage is a discussion of tape portability, and notes on how the GNU versions of those utilities stack up in that and other contexts. Even Unix administrators who aren't involved with backups regularly might find this chapter interesting, as the information about how to read an unfamiliar tape you've been given is alone is worth the price of the book if you're ever stuck in that situation.

For those looking to back up systems without much of a budget, a discussion of free backup tools ranges from writing scripts to automate the built-in Unix tools to coverage of the popular AMANDA backup system. The third section covers what to look for in a commercial backup product. This is light on specific recommendations, instead trying to educate the reader well enough to perform his or her own product selection. A somewhat related chapter covers the main ideas behind High Availability, which is obviously too big of a topic to cover fully in a 15-page section.

The next few chapters cover bare-metal backup and recovery, where the goal is to make a backup of the system capable of being used to create a new system in the event of a total failure. Many traditional solutions to this problem involve first re-installing the operating system, then restoring the backup. The author maintains this is a bad approach, and instead focuses on constructing a small bootable system (i.e. a Linux rescue floppy) capable of partitioning the drive and restoring the backup without laying down the OS first. SunOS/Solaris, Linux, Compaq True-64 Unix, HP-UX, IRIX and AIX are all covered.

Four chapters on database backup and recovery suggest how to integrate your backup solution with the database vendor's tools. Along with a general discussion aimed at bringing non-database administrators up to speed on DB lingo, separate chapters cover Informix, Oracle and Sybase. Finally, the three closing chapters to the book include miscellaneous information like backing up Rational's ClearCase product and selecting backup hardware, as well as some notes on upcoming trends.

Competent system administrators, either through forward thinking or past battle scars, develop a level of paranoia about their computers and how strongly their data should be protected that people outside the field find it hard to fathom. If you'd like to hone your own sense that everyone is out to get you, and know how to stop them, Unix Backup & Recovery is as good of an introduction to that topic as you'll find anywhere.

Buy this from ThinkGeek.

Table of Contents

1. Preparing for the Worst
2. Backing It All Up
3. Native Backup & Recovery Utilities
4. Free Backup Utilities
5. Commercial Backup Utilities
6. High Availability
7. Bare-Metal Backup & Recovery Methods: SunOS/Solaris
8. Bare-Metal: Linux
9. Bare-Metal: Compaq True-64 Unix
10. Bare-Metal: HP-UX
11. Bare-Metal: IRIX
12. Bare-Metal: AIX
13. Backing Up Databases
14. Informix Backup & Recovery
15. Oracle Backup & Recovery
16. Sybase Backup & Recovery
17. ClearCase Backup & Recovery
18. Backup Hardware
19. Miscellanea

Lawrence_Bird writes ... a group of scientists have extracted a wooly mammoth intact from a Siberian icefield. "They used a radar imaging technique to `see' the mammoth in its icy grave, then excavated a huge block of frozen dirt around it to preserve the 23,000-year-old creature." See the dailynews.yahoo story. Naturally, there's talk of cloning the thing. If the effort succeeds, will McDonald's sell McMammoth burgers?

Lawrence_Bird writes "Reuters put a piece out overnite commenting on the use of Linux in web appliances. It has a few quotes from Linus and comments specifically on TiVo Inc. " Comments on the RH IPO, Linux on Merced, and a few other bits.