2004.12_Put It in a Script.pdf

Scripting Secrets Intro

COVER STORY

Putitin a Script

Not every expert computer user is a programmer, but if you want to be an expert, you’d better know something about

scripting -- especially if you’re working in Linux. BY JOE CASAD

has always ascribed to the philoso-

phy of using simple tools in

interesting ways. A script is a way of

automating commands, but, as you will

see in this issue of Linux Magazine, a

script is also a means of connecting

tools. Every command is a tiny tool, of

course, but some tools are especially

useful for scripters. Some tools, in fact,

are whole languages that fit comfortably

within other languages so that you can

build better and more efficient scripts. In

this issue you’ll see examples of grep and

AWK, for instance. You’ll also get some

tips on scripting with Bash, and you’ll

learn about advanced scripting tech-

niques for conditional statements and

command substitution.

Because all tasks, and all Linux users,

are not the same, a variety of scripting

languages are available, and we touch on

some of the most important languages in

this issue.

We start out with an odyssey into

scripting with Bash (the Bourne Again

Shell). Bash, the default shell on many

Linux systems, will be very familiar to

many readers. But we wanted to go

beyond what most users see. In our lead-

off article, “Gaining Control: Building a

Bash Web Admin Script,” by Peer Hein-

lein, we show you a script for

administering a web server in a real-life

production environment. And as you

will see, the best part of the article isn’t

the commands but the techniques -- the

tricks for getting to an efficient solution

through advanced knowledge of script-

ing tools and the web service

infrastructure.

Next in the set is an article on the

classic Unix scripting language AWK.

The article “Regular Wizardry: AWK

with a Text-file Table,” by Nico

Hochgeschwender, shows

AWK in action. AWK has

been around so long

that almost everyone

has heard of it,

but, with the

variety of newer

and more ver-

satile

languages

available, one

does not always

think of AWK as

a tool of choice

for very practical

problems on the

modern network. In

this case, we’ll show you

a practical case study that

demonstrates

how a system

administrator

could use AWK to

search a text-file table

that contains configura-

tion information on network

computers.

Rounding out our set of scripting

themes is an advanced look at Perl 6

from Linux Magazine,’s regular Perl

columnist Mike Schilli. If you loved Perl

5, you might like Perl 6 even more. We’ll

give you a look at what’s ahead in the

the world of Perl.

And if you’re looking for another arti-

cle in this month’s issue that may be

interesting reading for scripting special-

ists, try Heike Jurzik’s piece on the

ImageMagick toolset. The ImageMagick

tools, which let you manipulate graphic

images through text-based commands,

could lead to imteresting possibilities if

you like to experiment and you’re in the

mood for some scripting.

■

COVER STORY

Bash scripting ...................... 20

PutBash to work on your network. You can

use Bash to check up on your web server.

You’ll learn how Bash can help you with

checking your server’s status and hunting

for hidden root users.

AWK ........................................ 30

A practical look at using AWK to access and

manage a text-file table.

Perl 6 Preview ....................... 33

Linux Magazine Perl columnist Mike Schilli

takes an inside look at soon-to-be-release

Perl 6. Learn about what’s coming in the

brand new Perl.

www.linux-magazine.com December 2004

Techniques for scripting in Linux

L inux is a godchild of Unix, and Unix

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