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NAME

perl - The Perl 5 language interpreter

SYNOPSIS

perl-sTtuUWX ] [ -hv ] [ -V[:configvar] ] [ -cw ] [ -d[t][:debugger] ] [ -D[number/list] ] [ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal/hexadecimal] ] [ -Idir ] [ -m[-]module ] [ -M[-]'module...' ] [ -f ] [ -C [f(BInumber/list] [ -S ] [ -x[dir] ] [ -i[extension] ] [ [-e|-E'command' ] [ -- ] [ programfile ] [ argument ]...

For more information on these options, you can run f(CW*(C`perldoc perlrun*(C'.

GETTING HELP

The perldoc program gives you access to all the documentation that comes with Perl. You can get more documentation, tutorials and community support online at <http://www.perl.org/>.

If you're new to Perl, you should start by running f(CW*(C`perldoc perlintro*(C', which is a general intro for beginners and provides some background to help you navigate the rest of Perl's extensive documentation. Run f(CW*(C`perldoc perldoc*(C' to learn more things you can do with perldoc.

For ease of access, the Perl manual has been split up into several sections.

Overview

  perl Perl overview (this section)   perlintro Perl introduction for beginners   perlrun Perl execution and options   perltoc Perl documentation table of contents

Tutorials

  perlreftut Perl references short introduction   perldsc Perl data structures intro   perllol Perl data structures: arrays of arrays

  perlrequick Perl regular expressions quick start   perlretut Perl regular expressions tutorial

  perlootut Perl OO tutorial for beginners

  perlperf Perl Performance and Optimization Techniques

  perlstyle Perl style guide

  perlcheat Perl cheat sheet   perltrap Perl traps for the unwary   perldebtut Perl debugging tutorial

  perlfaq Perl frequently asked questions   perlfaq1 General Questions About Perl   perlfaq2 Obtaining and Learning about Perl   perlfaq3 Programming Tools   perlfaq4 Data Manipulation   perlfaq5 Files and Formats   perlfaq6 Regexes   perlfaq7 Perl Language Issues   perlfaq8 System Interaction   perlfaq9 Networking

Reference Manual

  perlsyn Perl syntax   perldata Perl data structures   perlop Perl operators and precedence   perlsub Perl subroutines   perlfunc Perl built-in functions   perlopentut Perl open() tutorial   perlpacktut Perl pack() and unpack() tutorial   perlpod Perl plain old documentation   perlpodspec Perl plain old documentation format specification   perlpodstyle Perl POD style guide   perldiag Perl diagnostic messages   perllexwarn Perl warnings and their control   perldebug Perl debugging   perlvar Perl predefined variables   perlre Perl regular expressions, the rest of the story   perlrebackslash Perl regular expression backslash sequences   perlrecharclass Perl regular expression character classes   perlreref Perl regular expressions quick reference   perlref Perl references, the rest of the story   perlform Perl formats   perlobj Perl objects   perltie Perl objects hidden behind simple variables   perldbmfilter Perl DBM filters

  perlipc Perl interprocess communication   perlfork Perl fork() information   perlnumber Perl number semantics

  perlthrtut Perl threads tutorial

  perlport Perl portability guide   perllocale Perl locale support   perluniintro Perl Unicode introduction   perlunicode Perl Unicode support   perlunicook Perl Unicode cookbook   perlunifaq Perl Unicode FAQ   perluniprops Index of Unicode properties in Perl   perlunitut Perl Unicode tutorial   perlebcdic Considerations for running Perl on EBCDIC platforms

  perlsec Perl security

  perlmod Perl modules: how they work   perlmodlib Perl modules: how to write and use   perlmodstyle Perl modules: how to write modules with style   perlmodinstall Perl modules: how to install from CPAN   perlnewmod Perl modules: preparing a new module for distribution   perlpragma Perl modules: writing a user pragma

  perlutil utilities packaged with the Perl distribution

  perlfilter Perl source filters

  perldtrace Perl*(Aqs support for DTrace

  perlglossary Perl Glossary

Internals and C Language Interface

  perlembed Perl ways to embed perl in your C or C++ application   perldebguts Perl debugging guts and tips   perlxstut Perl XS tutorial   perlxs Perl XS application programming interface   perlxstypemap Perl XS C/Perl type conversion tools   perlclib Internal replacements for standard C library functions   perlguts Perl internal functions for those doing extensions   perlcall Perl calling conventions from C   perlmroapi Perl method resolution plugin interface   perlreapi Perl regular expression plugin interface   perlreguts Perl regular expression engine internals

  perlapi Perl API listing (autogenerated)   perlintern Perl internal functions (autogenerated)   perliol C API for Perl*(Aqs implementation of IO in Layers   perlapio Perl internal IO abstraction interface

  perlhack Perl hackers guide   perlsource Guide to the Perl source tree   perlinterp Overview of the Perl interpreter source and how it works   perlhacktut Walk through the creation of a simple C code patch   perlhacktips Tips for Perl core C code hacking   perlpolicy Perl development policies   perlgit Using git with the Perl repository

Miscellaneous

  perlbook Perl book information   perlcommunity Perl community information

  perldoc Look up Perl documentation in Pod format

  perlhist Perl history records   perldelta Perl changes since previous version   perl5201delta Perl changes in version 5.20.1   perl5200delta Perl changes in version 5.20.0   perl5184delta Perl changes in version 5.18.4   perl5182delta Perl changes in version 5.18.2   perl5181delta Perl changes in version 5.18.1   perl5180delta Perl changes in version 5.18.0   perl5163delta Perl changes in version 5.16.3   perl5162delta Perl changes in version 5.16.2   perl5161delta Perl changes in version 5.16.1   perl5160delta Perl changes in version 5.16.0   perl5144delta Perl changes in version 5.14.4   perl5143delta Perl changes in version 5.14.3   perl5142delta Perl changes in version 5.14.2   perl5141delta Perl changes in version 5.14.1   perl5140delta Perl changes in version 5.14.0   perl5125delta Perl changes in version 5.12.5   perl5124delta Perl changes in version 5.12.4   perl5123delta Perl changes in version 5.12.3   perl5122delta Perl changes in version 5.12.2   perl5121delta Perl changes in version 5.12.1   perl5120delta Perl changes in version 5.12.0   perl5101delta Perl changes in version 5.10.1   perl5100delta Perl changes in version 5.10.0   perl589delta Perl changes in version 5.8.9   perl588delta Perl changes in version 5.8.8   perl587delta Perl changes in version 5.8.7   perl586delta Perl changes in version 5.8.6   perl585delta Perl changes in version 5.8.5   perl584delta Perl changes in version 5.8.4   perl583delta Perl changes in version 5.8.3   perl582delta Perl changes in version 5.8.2   perl581delta Perl changes in version 5.8.1   perl58delta Perl changes in version 5.8.0   perl561delta Perl changes in version 5.6.1   perl56delta Perl changes in version 5.6   perl5005delta Perl changes in version 5.005   perl5004delta Perl changes in version 5.004

  perlexperiment A listing of experimental features in Perl

  perlartistic Perl Artistic License   perlgpl GNU General Public License

Language-Specific

  perlcn Perl for Simplified Chinese (in EUC-CN)   perljp Perl for Japanese (in EUC-JP)   perlko Perl for Korean (in EUC-KR)   perltw Perl for Traditional Chinese (in Big5)

Platform-Specific

  perlaix Perl notes for AIX   perlamiga Perl notes for AmigaOS   perlandroid Perl notes for Android   perlbs2000 Perl notes for POSIX-BC BS2000   perlce Perl notes for WinCE   perlcygwin Perl notes for Cygwin   perldos Perl notes for DOS   perlfreebsd Perl notes for FreeBSD   perlhaiku Perl notes for Haiku   perlhpux Perl notes for HP-UX   perlhurd Perl notes for Hurd   perlirix Perl notes for Irix   perllinux Perl notes for Linux   perlmacos Perl notes for Mac OS (Classic)   perlmacosx Perl notes for Mac OS X   perlnetware Perl notes for NetWare   perlopenbsd Perl notes for OpenBSD   perlos2 Perl notes for OS/2   perlos390 Perl notes for OS/390   perlos400 Perl notes for OS/400   perlplan9 Perl notes for Plan 9   perlqnx Perl notes for QNX   perlriscos Perl notes for RISC OS   perlsolaris Perl notes for Solaris   perlsymbian Perl notes for Symbian   perlsynology Perl notes for Synology   perltru64 Perl notes for Tru64   perlvms Perl notes for VMS   perlvos Perl notes for Stratus VOS   perlwin32 Perl notes for Windows

Stubs for Deleted Documents

  perlboot   perlbot   perlrepository   perltodo   perltooc   perltoot

On Debian systems, you need to install the perl-doc package which contains the majority of the standard Perl documentation and the perldoc program.

Extensive additional documentation for Perl modules is available, both those distributed with Perl and third-party modules which are packaged or locally installed.

You should be able to view Perl's documentation with your man|(1) program or perldoc|(1).

Some documentation is not available as man pages, so if a cross-reference is not found by man, try it with perldoc. Perldoc can also take you directly to documentation for functions (with the -f switch). See f(CW*(C`perldoc --help*(C' (or f(CW*(C`perldoc perldoc*(C' or f(CW*(C`man perldoc*(C') for other helpful options perldoc has to offer.

In general, if something strange has gone wrong with your program and you're not sure where you should look for help, try making your code comply with use strict and use warnings. These will often point out exactly where the trouble is.

DESCRIPTION

Perl officially stands for Practical Extraction and Report Language, except when it doesn't.

Perl was originally a language optimized for scanning arbitrary text files, extracting information from those text files, and printing reports based on that information. It quickly became a good language for many system management tasks. Over the years, Perl has grown into a general-purpose programming language. It's widely used for everything from quick *(L"one-liners*(R" to full-scale application development.

The language is intended to be practical (easy to use, efficient, complete) rather than beautiful (tiny, elegant, minimal). It combines (in the author's opinion, anyway) some of the best features of sed, awk, and sh, making it familiar and easy to use for Unix users to whip up quick solutions to annoying problems. Its general-purpose programming facilities support procedural, functional, and object-oriented programming paradigms, making Perl a comfortable language for the long haul on major projects, whatever your bent.

Perl's roots in text processing haven't been forgotten over the years. It still boasts some of the most powerful regular expressions to be found anywhere, and its support for Unicode text is world-class. It handles all kinds of structured text, too, through an extensive collection of extensions. Those libraries, collected in the s-1CPAN,s0 provide ready-made solutions to an astounding array of problems. When they haven't set the standard themselves, they steal from the best *(-- just like Perl itself.

AVAILABILITY

Perl is available for most operating systems, including virtually all Unix-like platforms. See *(L"Supported Platforms*(R" in perlport for a listing.

ENVIRONMENT

See perlrun.

AUTHOR

Larry Wall <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 perl-thanks@perl.org .

FILES

 "@INC" locations of perl libraries

SEE ALSO

 http://www.perl.org/ the Perl homepage  http://www.perl.com/ Perl articles (O*(AqReilly)  http://www.cpan.org/ the Comprehensive Perl Archive  http://www.pm.org/ the Perl Mongers

DIAGNOSTICS

Using the f(CW*(C`use strict*(C' pragma ensures that all variables are properly declared and prevents other misuses of legacy Perl features.

The f(CW*(C`use warnings*(C' pragma produces some lovely diagnostics. One can also use the -w flag, but its use is normally discouraged, because it gets applied to all executed Perl code, including that not under your control.

See perldiag for explanations of all Perl's diagnostics. The f(CW*(C`use diagnostics*(C' pragma automatically turns Perl's normally terse warnings and errors into these longer forms.

Compilation errors will tell you the line number of the error, with an indication of the next token or token type that was to be examined. (In a script passed to Perl via -e switches, each -e is counted as one line.)

Setuid scripts have additional constraints that can produce error messages such as *(L"Insecure dependency*(R". See perlsec.

Did we mention that you should definitely consider using the use warnings pragma?

BUGS

The behavior implied by the use warnings pragma is not mandatory.

Perl is at the mercy of your machine's definitions of various 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() and syswrite().)

While none of the built-in data types have any arbitrary size limits (apart from memory size), there are still a few arbitrary limits: a given variable name may not be longer than 251 characters. Line numbers displayed by diagnostics are internally stored as short integers, so they are limited to a maximum of 65535 (higher numbers usually being affected by wraparound).

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 f(CW*(C`perl -V*(C') to perlbug@perl.org . If you've succeeded in compiling perl, the perlbug script in the utils/ subdirectory can be used to help mail in a bug report.

Perl actually stands for Pathologically Eclectic Rubbish Lister, but don't tell anyone I said that.

NOTES

The Perl motto is *(L"There's more than one way to do it.*(R" Divining how many more is left as an exercise to the reader.

The three principal virtues of a programmer are Laziness, Impatience, and Hubris. See the Camel Book for why.