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Book Rookery: Wicked Cool Shell Scripts

101 different, fun, and useful shell scripts

In this installment of the Book Rookery, Martin C. Brown speaks with Dave Taylor, author of Wicked Cool Shell Scripts, about all the fun things you can do with shell scripts, whether you're running Linux, Mac OS X, or even a mainstream Unix system.

Can you tell us more about the book and what's inside?

For years I've picked up different programming books and lamented that they weren't fun or interesting. In the shell scripting world, it's even worse, with book after book talking about how to use an "if" statement, but none containing fun, hip, edgy, and even kind of wacky shell scripts that demonstrate all sorts of useful constructs and capabilities, but focus on being interesting. That's exactly what I've done with my book, though. I skip all the how-to and instructional material - after all, there's tons of stuff online nowadays anyway - and jump straight into the content, into listing and explaining 101 different, fun, and useful shell scripts.

What's your favorite script in the book?

Well, I had the most fun figuring out how to get the hangman game (#100) to work in as few lines as possible. A flashback to my early programming life when "toss in more RAM" wasn't the solution to a bloated app! In terms of scripts I use every day, the Mac OS X "titleterm" script (#96) is just part of my everyday activity, and I really like the concepts embodied in the bestcompress script (#38) too.

What's the biggest challenge about using shell scripts?

At the end of the day, shell scripts can only be so sophisticated. My rule of thumb is that if the script is growing to be more than 200 lines or so, it's probably time to migrate to a more sophisticated programming environment. For me, it's just about always a switch into C, but I'm an old-time Unix guy so C is second nature to me.

Shell scripts? Why wouldn't people use Perl?

Perl is a viable option, but what I think is really great about shell scripts is that everyone who uses Unix, Linux, or the terminal in Mac OS X already has 90% of the skills and expertise needed to begin creating their own shell scripts. Further, every line you type into a shell script can be easily tested at a command line, so I'll often start out a script by building a longer and longer pipe of commands, then eventually just copy and paste the entire command sequence into a file and poof a new script is born.

There are lots of different Unix-related books - including a number that you've written - and shell script books. Why another one?

Yes, I admit, I've written Teach Yourself Unix in 24 Hours, Teach Yourself Unix System Administration in 24 Hours, and Unix: Man or Beast?. No, wait. Only the first two titles. Sorry.

More seriously, there are lots of books on Unix and Unix-related topics, but they almost all focus on being either dry reference works (five lines and a table of flags for all 1,600 commands included with your OS, yawn) or on step-by-step tutorials (both of my books fall into this category, the "12,158 simple steps to becoming a Unix expert" style), but there are way too few books that are fun and entertaining, choosing to teach through example and through sheer enthusiasm for the environment. Wicked Cool Shell Scripts endeavors to fill this gap and so far, based on the tremendous response from the Unix and open source community, it's hitting its mark.

What's your take on the SCO lawsuit?

I've always wondered about people who put more energy into dragging innovators back to the status quo than in innovating themselves, and I think that's exactly what the SCO team is doing. Last I checked, they weren't doing anything interesting or innovative with Unix, so why would they want to slow the rest of us down? I won't go into conspiracy theories, but there sure are a lot of curious coincidences in this situation. Ultimately, though, I'd like to see the open source community cut SCO off at the knees: work with legal people to identify exactly what code SCO believes is questionable and then have swarms of programmers en masse toss that code out of the Linux code base and rewrite all of it "black box" so that SCO is left holding... nothing.

And in the meantime, innovative work with GNOME, the new kernel, autodiscovery of network resources, further levels of compatibility with samba, and other innovations are the lifeblood of our community, and they're what I'd like to see everyone continue to focus on developing.

Your book also covers Mac OS X: What OS do you run on your main computer, and how Unix-y do you think Mac OS X really is, when compared to a distro like Fedora?

I have always been a huge fan of Macs, I have to admit. I remember many, many years ago when I first used a 512K Mac (which was loaned to me by the Whole Earth ‘Lectronic Link, of all groups) and realized that it was a whole new way of looking at usability. This was after years of HP's Windex and X (and I remember when Motif was state of the art, gawd!), but it was so clearly superior... I've been a die-hard Mac person ever since and now I have four Macs in my office, including a brand-new dual G5 system. They not only run Mac OS X but my Terminal window is always open too. It's a fabulous pairing of all the power and capabilities of Unix with the GUI and graphical good karma of Aqua, the Mac OS X graphical environment. It rocks!

And finally, what editor do you like, emacs or vi?

Oh boy. I'm a "vi" person and have been forever. Thank you Bill for your work in this area, even if it was oh, so many years ago. However, kudos to the vim team too: vim finally fixes all the annoying limitations of vi.

About the Author
Dave Taylor is author of 15 computer books, including Learning Unix for Mac OS X Panther and Creating Cool Web Sites. You can learn more about Wicked Cool Shell Scripts - and read through the scripts - online at

More Stories By Martin C. Brown

Martin C. Brown is a former IT director with experience in cross-platform integration. A keen developer, he has produced dynamic sites for blue-chip customers, including HP and Oracle, and is the technical director of Now a freelance writer and consultant, MC, as he is better known, works closely with Microsoft as an SME; has a regular column on both and IBM's DeveloperWorks Grid Computing site; is a core member of the team; and has written books such as XML Processing with Perl, Python and PHP, and the Microsoft IIS 6 Delta Guide.

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