User guide
Chapter 3. Libraries and Runtime Support
38
3.3.9.3. Perl Documentation
The perldoc tool provides documentation on language and core modules. To learn more about a
module, use perldoc module_name. For example, perldoc CGI will display the following information
about the CGI core module:
NAME
CGI - Handle Common Gateway Interface requests and responses
SYNOPSIS
use CGI;
my $q = CGI->new;
[...]
DESCRIPTION
CGI.pm is a stable, complete and mature solution for processing and preparing HTTP requests
and responses. Major features including processing form submissions, file uploads, reading
and writing cookies, query string generation and manipulation, and processing and preparing
HTTP headers. Some HTML generation utilities are included as well.
[...]
PROGRAMMING STYLE
There are two styles of programming with CGI.pm, an object-oriented style and a function-
oriented style. In the object-oriented style you create one or more CGI objects and then use
object methods to create the various elements of the page. Each CGI object starts out with
the list of named parameters that were passed to your CGI script by the server.
[...]
For details on Perl functions, use perldoc -f function_name. For example, perldoc -f split wil
display the following indormation about the split function:
split /PATTERN/,EXPR,LIMIT
split /PATTERN/,EXPR
split /PATTERN/
split Splits the string EXPR into a list of strings and returns that list. By default,
empty leading fields are preserved, and empty trailing ones are deleted. (If all fields are
empty, they are considered to be trailing.)
In scalar context, returns the number of fields found. In scalar and void context it splits
into the @_ array. Use of split in scalar and void context is deprecated, however, because
it clobbers your subroutine arguments.
If EXPR is omitted, splits the $_ string. If PATTERN is also omitted, splits on whitespace
(after skipping any leading whitespace). Anything matching PATTERN is taken to be
a delimiter separating the fields. (Note that the delimiter may be longer than one
character.)
[...]
Current PerlDoc documentation can be found on perldoc.perl.org
19
.
Core and external modules are documented on the Comprehensive Perl Archive Network
20
.
19
http://perldoc.perl.org/
20
http://www.cpan.org/