perl Perl overview (this section)
perldelta Perl changes since previous version
+ perlfaq Perl frequently asked questions
perldata Perl data structures
perlsyn Perl syntax
perlfunc Perl builtin functions
perlvar Perl predefined variables
perlsub Perl subroutines
- perlmod Perl modules
+ perlmod Perl modules: how they work
+ perlmodlib Perl modules: how to write and use
perlform Perl formats
perllocale Perl locale support
- perlref Perl references
+ perlref Perl references
perldsc Perl data structures intro
perllol Perl data structures: lists of lists
perltoot Perl OO tutorial
perlpod Perl plain old documentation
perlbook Perl book information
- perlembed Perl how to embed perl in your C or C++ app
+ perlembed Perl ways to embed perl in your C or C++ application
perlapio Perl internal IO abstraction interface
perlxs Perl XS application programming interface
perlxstut Perl XS tutorial
- perlguts Perl internal functions for those doing extensions
+ perlguts Perl internal functions for those doing extensions
perlcall Perl calling conventions from C
+ perlhist Perl history records
+
(If you're intending to read these straight through for the first time,
the suggested order will tend to reduce the number of forward references.)
-Additional documentation for Perl modules is available in the
-F</usr/local/man/> directory. Some of this is distributed standard with
-Perl, but you'll also find third-party modules there. You should be able
-to view this with your man(1) program by including the proper directories
-in the appropriate start-up files. To find out where these are, type:
+By default, all of the above manpages are installed in the
+F</usr/local/man/> directory.
+
+Extensive additional documentation for Perl modules is available. The
+default configuration for perl will place this additional documentation
+in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
+subdirectory of the Perl library directory). Some of this additional
+documentation is distributed standard with Perl, but you'll also find
+documentation for third-party modules there.
+
+You should be able to view Perl's documentation with your man(1)
+program by including the proper directories in the appropriate start-up
+files, or in the MANPATH environment variable. To find out where the
+configuration has installed the manpages, type:
perl -V:man.dir
-If the directories were F</usr/local/man/man1> and F</usr/local/man/man3>,
-you would need to add only F</usr/local/man> to your MANPATH. If
-they are different, you'll have to add both stems.
+If the directories have a common stem, such as F</usr/local/man/man1>
+and F</usr/local/man/man3>, you need only to add that stem
+(F</usr/local/man>) to your man(1) configuration files or your MANPATH
+environment variable. If they do not share a stem, you'll have to add
+both stems.
If that doesn't work for some reason, you can still use the
supplied F<perldoc> script to view module information. You might
(easy to use, efficient, complete) rather than beautiful (tiny,
elegant, minimal).
-Perl combines (in the author's opinion, anyway) some
-of the best features of C, B<sed>, B<awk>, and B<sh>, so people
-familiar with those languages should have little difficulty with it.
-(Language historians will also note some vestiges of B<csh>, Pascal,
-and even BASIC-PLUS.) Expression syntax corresponds quite closely to C
+Perl combines (in the author's opinion, anyway) some of the best
+features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
+those languages should have little difficulty with it. (Language
+historians will also note some vestiges of B<csh>, Pascal, and even
+BASIC-PLUS.) Expression syntax corresponds quite closely to C
expression syntax. Unlike most Unix utilities, Perl does not
arbitrarily limit the size of your data--if you've got the memory,
-Perl can slurp in your whole file as a single string. Recursion is
-of unlimited depth. And the hash tables used by associative arrays
-grow as necessary to prevent degraded performance. Perl uses
-sophisticated pattern matching techniques to scan large amounts of data
-very quickly. Although optimized for scanning text, Perl can also
-deal with binary data, and can make dbm files look like associative
-arrays. Setuid Perl scripts are safer than
-C programs through a dataflow tracing mechanism which prevents many
-stupid security holes. If you have a problem that would ordinarily use
-B<sed> or B<awk> or B<sh>, but it exceeds their capabilities or must
-run a little faster, and you don't want to write the silly thing in C,
-then Perl may be for you. There are also translators to turn your
-B<sed> and B<awk> scripts into Perl scripts.
+Perl can slurp in your whole file as a single string. Recursion is of
+unlimited depth. And the tables used by hashes (previously called
+"associative arrays") grow as necessary to prevent degraded
+performance. Perl uses sophisticated pattern matching techniques to
+scan large amounts of data very quickly. Although optimized for
+scanning text, Perl can also deal with binary data, and can make dbm
+files look like hashes. Setuid Perl scripts are safer than C programs
+through a dataflow tracing mechanism which prevents many stupid
+security holes.
+
+If you have a problem that would ordinarily use B<sed> or B<awk> or
+B<sh>, but it exceeds their capabilities or must run a little faster,
+and you don't want to write the silly thing in C, then Perl may be for
+you. There are also translators to turn your B<sed> and B<awk>
+scripts into Perl scripts.
But wait, there's more...
Perl variables may now be declared within a lexical scope, like "auto"
variables in C. Not only is this more efficient, but it contributes
-to better privacy for "programming in the large". Anonymous
+to better privacy for "programming in the large". Anonymous
subroutines exhibit deep binding of lexical variables (closures).
=item * Arbitrarily nested data structures
=item * Regular expression enhancements
-You can now specify non-greedy quantifiers. You can now do grouping
+You can now specify nongreedy quantifiers. You can now do grouping
without creating a backreference. You can now write regular expressions
with embedded whitespace and comments for readability. A consistent
extensibility mechanism has been added that is upwardly compatible with
=item * Innumerable Unbundled Modules
-The Comprehensive Perl Archive Network described in L<perlmod>
-contains hundreds of plug-and-play modules full of reusable
-code. See F<http://www.perl.com/CPAN> for a site near you.
+The Comprehensive Perl Archive Network described in L<perlmodlib>
+contains hundreds of plug-and-play modules full of reusable code.
+See F<http://www.perl.com/CPAN> for a site near you.
=item * Compilability
While not yet in full production mode, a working perl-to-C compiler
-does exist. It can generate portable bytecode, simple C, or
+does exist. It can generate portable byte code, simple C, or
optimized C code.
=back
-Ok, that's I<definitely> enough hype.
+Okay, that's I<definitely> enough hype.
=head1 ENVIRONMENT
-=over 12
-
-=item HOME
-
-Used if chdir has no argument.
-
-=item LOGDIR
-
-Used if chdir has no argument and HOME is not set.
-
-=item PATH
-
-Used in executing subprocesses, and in finding the script if B<-S> is
-used.
-
-=item PERL5LIB
-
-A colon-separated list of directories in which to look for Perl library
-files before looking in the standard library and the current
-directory. If PERL5LIB is not defined, PERLLIB is used. When running
-taint checks (because the script was running setuid or setgid, or the
-B<-T> switch was used), neither variable is used. The script should
-instead say
-
- use lib "/my/directory";
-
-=item PERL5DB
-
-The command used to get the debugger code. If unset, uses
-
- BEGIN { require 'perl5db.pl' }
-
-=item PERL_DESTRUCT_LEVEL
-
-Relevant only if your perl executable was built with B<-DDEBUGGING>,
-this controls the behavior of global destruction of objects and other
-references.
-
-=item PERLLIB
-
-A colon-separated list of directories in which to look for Perl library
-files before looking in the standard library and the current
-directory. If PERL5LIB is defined, PERLLIB is not used.
-
-=back
-
-Perl also has environment variables that control how Perl handles data
-specific to particular natural languages. See L<perllocale>.
-
-Apart from these, Perl uses no other environment variables, except
-to make them available to the script being executed, and to child
-processes. However, scripts running setuid would do well to execute
-the following lines before doing anything else, just to keep people
-honest:
-
- $ENV{'PATH'} = '/bin:/usr/bin'; # or whatever you need
- $ENV{'SHELL'} = '/bin/sh' if defined $ENV{'SHELL'};
- $ENV{'IFS'} = '' if defined $ENV{'IFS'};
+See L<perlrun>.
=head1 AUTHOR
-Larry Wall E<lt>F<larry@wall.org>E<gt>, with the help of oodles of other folks.
+Larry Wall <F<larry@wall.org>>, with the help of oodles of other folks.
+
+If your Perl success stories and testimonials may be of help to others
+who wish to advocate the use of Perl in their applications,
+or if you wish to simply express your gratitude to Larry and the
+Perl developers, please write to <F<perl-thanks@perl.org>>.
=head1 FILES
The B<-w> switch is not mandatory.
Perl is at the mercy of your machine's definitions of various
-operations such as type casting, atof(), and sprintf(). The latter
-can even trigger a core dump when passed ludicrous input values.
+operations such as type casting, atof(), and floating-point
+output with sprintf().
If your stdio requires a seek or eof between reads and writes on a
particular stream, so does Perl. (This doesn't apply to sysread()
You may mail your bug reports (be sure to include full configuration
information as output by the myconfig program in the perl source tree,
-or by C<perl -V>) to F<perlbug@perl.com>.
+or by C<perl -V>) to <F<perlbug@perl.com>>.
If you've succeeded in compiling perl, the perlbug script in the utils/
subdirectory can be used to help mail in a bug report.