Perl Cd Bookshelf [Electronic resources] نسخه متنی

0.5.1. Programming Conventions

We give lots of examples, most of which are pieces of code that
should go into a larger program. Some examples are complete programs,
which you can recognize because they begin with a
#! line. We start nearly all of our longer
programs with:

#!/usr/bin/perl -w
use strict;

or else the newer:

#!/usr/bin/perl
use strict;
use warnings;

Still other examples are things to be typed on a command line. We've
used % to show the shell prompt:

% perl -e 'print "Hello, world.\n"'
Hello, world.

This style represents a standard Unix command line, where single
quotes represent the "most quoted" form. Quoting and wildcard
conventions on other systems vary. For example, many command-line
interpreters under MS-DOS and VMS require double quotes instead of
single ones to group arguments with spaces or wildcards in them.

The following typographic conventions are used in this book:

Bold
is used exclusively for command-line switches. This allows one to
distinguish for example, between the -w warnings switch and the
-w filetest operator.

Italic
is used for URLs, manpages, pathnames, and programs. New terms are
also italicized when they first appear in the text.

Constant Width
is used for function and method names and their arguments; in
examples to show text that you enter verbatim; and in regular text to
show literal code.

Constant Width Bold Italic
is used in examples to show output produced.

The most up-to-date and complete documentation about Perl is included
with Perl itself. If typeset and printed, this massive anthology
would use more than a thousand pages of printed paper, greatly
contributing to global deforestation. Fortunately, you don't have to
print it out, because it's available in a convenient and searchable
electronic form.