This introductory document does not aim to be complete. It does not
even aim to be entirely accurate. In some cases perfection has been
sacrificed in the goal of getting the general idea across. You are
-B<strongly> advised to follow this introduction with more information
+I<strongly> advised to follow this introduction with more information
from the full Perl manual, the table of contents to which can be found
in L<perltoc>.
Throughout this document you'll see references to other parts of the
Perl documentation. You can read that documentation using the C<perldoc>
-command or using whatever method you're using to read this document.
+command or whatever method you're using to read this document.
=head2 What is Perl?
system administration, web development, network programming, GUI
development, and more.
-The language is intended to be practical (easy to use, efficient,
-complete) rather than beautiful (tiny, elegant, minimal). Its major
-features are that it's easy to use, supports both procedural and OO
-programming, has powerful built-in support for text processing, and
-has one of the world's most impressive collections of third-party
-modules.
+The language is intended to be practical (easy to use, efficient,
+complete) rather than beautiful (tiny, elegant, minimal). Its major
+features are that it's easy to use, supports both procedural and
+object-oriented (OO) programming, has powerful built-in support for text
+processing, and has one of the world's most impressive collections of
+third-party modules.
Different definitions of Perl are given in L<perl>, L<perlfaq1> and
no doubt other places. From this we can determine that Perl is different
to be executable first, so C<chmod 755 script.pl> (under Unix).
For more information, including instructions for other platforms such as
-Windows and MacOS, read L<perlrun>.
+Windows and Mac OS, read L<perlrun>.
=head2 Basic syntax overview
A Perl script or program consists of one or more statements. These
statements are simply written in the script in a straightforward
-fashion. There is no need to have a main() function or anything of that
-kind.
+fashion. There is no need to have a C<main()> function or anything of
+that kind.
Perl statements end in a semi-colon:
we're getting just a single value out of the array -- you ask for a scalar,
you get a scalar.
-To get multiple values from a array:
+To get multiple values from an array:
@animals[0,1]; # gives ("camel", "llama");
@animals[0..2]; # gives ("camel", "llama", "owl");
=head2 Conditional and looping constructs
Perl has most of the usual conditional and looping constructs except for
-case/switch (but you can find a Switch module on CPAN, if you really
-want one -- see the section on modules, below, for more information
-about modules and CPAN).
+case/switch (but if you really want it, there is a Switch module in Perl
+5.8 and newer, and on CPAN. See the section on modules, below, for more
+information about modules and CPAN).
The conditions can be any Perl expression. See the list of operators in
the next section for information on comparison and boolean logic operators,
...
}
-This is provided as a more readable version of C<if (! condition)>.
+This is provided as a more readable version of C<if (!I<condition>)>.
Note that the braces are required in Perl, even if you've only got one
line in the block. However, there is a clever way of making your one-line
}
The C style for loop is rarely needed in Perl since Perl provides
-the the more friendly list scanning C<foreach> loop.
+the more friendly list scanning C<foreach> loop.
=item foreach
Perl comes with a wide selection of builtin functions. Some of the ones
we've already seen include C<print>, C<sort> and C<reverse>. A list of
them is given at the start of L<perlfunc> and you can easily read
-about any given function by using C<perldoc -f functionname>.
+about any given function by using C<perldoc -f I<functionname>>.
Perl operators are documented in full in L<perlop>, but here are a few
of the most common ones:
# a cheap and nasty way to break an email address up into parts
- if ($email =~ /([^@]+@(.+)/) {
+ if ($email =~ /([^@])+@(.+)/) {
print "Username is $1\n";
print "Hostname is $2\n";
}
=head2 Using Perl modules
Perl modules provide a range of features to help you avoid reinventing
-the wheel, and can be downloaded from CPAN (http://www.cpan.org). A
+the wheel, and can be downloaded from CPAN ( http://www.cpan.org/ ). A
number of popular modules are included with the Perl distribution
itself.
To learn how to install modules you download from CPAN, read
L<perlmodinstall>
-To learn how to use a particular module, use C<perldoc Module::Name>.
-Typically you will want to C<use Module::Name>, which will then give you
-access to exported functions or an OO interface to the module.
+To learn how to use a particular module, use C<perldoc I<Module::Name>>.
+Typically you will want to C<use I<Module::Name>>, which will then give
+you access to exported functions or an OO interface to the module.
L<perlfaq> contains questions and answers related to many common
tasks, and often provides suggestions for good CPAN modules to use.
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