PERL(1)		       Perl Programmers Reference Guide		       PERL(1)



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 [number/list] ]      [ -S ]	  [ -x[dir] ]
	    [ -i[extension] ]
	    [ [-e|-E] 'command' ] [ -- ] [ programfile ] [ argument ]...

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 "perldoc perlintro",
       which is a general intro for beginners and provides some background to
       help you navigate the rest of Perl's extensive documentation.  Run
       "perldoc perldoc" 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
	   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
	   perlrun	       Perl execution and options
	   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
	   perlunifaq	       Perl Unicode FAQ
	   perluniprops	       Index of Unicode Version 6.0.0 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's 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's 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
	   perl5162delta       Perl changes in version 5.16.2
	   perl5161delta       Perl changes in version 5.16.1
	   perl5160delta       Perl changes in version 5.16.0
	   perl5160delta       Perl changes in version 5.16.0
	   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
	   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
	   perlbeos	       Perl notes for BeOS
	   perlbs2000	       Perl notes for POSIX-BC BS2000
	   perlce	       Perl notes for WinCE
	   perlcygwin	       Perl notes for Cygwin
	   perldgux	       Perl notes for DG/UX
	   perldos	       Perl notes for DOS
	   perlepoc	       Perl notes for EPOC
	   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
	   perlmpeix	       Perl notes for MPE/iX
	   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
	   perltru64	       Perl notes for Tru64
	   perluts	       Perl notes for UTS
	   perlvmesa	       Perl notes for VM/ESA
	   perlvms	       Perl notes for VMS
	   perlvos	       Perl notes for Stratus VOS
	   perlwin32	       Perl notes for Windows

   Stubs for Deleted Documents
	   perlboot
	   perlbot
	   perltodo
	   perltooc
	   perltoot

       On a Unix-like system, these documentation files will usually also be
       available as manpages for use with the man program.

       In general, if something strange has gone wrong with your program and
       you're not sure where you should look for help, try the -w switch
       first.  It 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 "one-liners" to full-scale application development.

       The language is intended to be practical (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, sed, awk, and sh, so people familiar with those
       languages should have little difficulty with it.	 (Language historians
       will also note some vestiges of csh, Pascal, and even BASIC-PLUS.)
       Expression syntax corresponds 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 tables used
       by hashes (sometimes called "associative arrays") grow as necessary to
       prevent degraded performance.  Perl can use sophisticated pattern
       matching techniques to scan large amounts of data quickly.  Although
       optimized for scanning text, Perl also has many excellent tools for
       slicing and dicing binary data.

       But wait, there's more...

       Begun in 1993 (see perlhist), Perl version 5 is nearly a complete
       rewrite that provides the following additional benefits:

       o   modularity and reusability using innumerable modules

	   Described in perlmod, perlmodlib, and perlmodinstall.

       o   embeddable and extensible

	   Described in perlembed, perlxstut, perlxs, perlxstypemap, perlcall,
	   perlguts, and xsubpp.

       o   roll-your-own magic variables (including multiple simultaneous DBM
	   implementations)

	   Described in perltie and AnyDBM_File.

       o   subroutines can now be overridden, autoloaded, and prototyped

	   Described in perlsub.

       o   arbitrarily nested data structures and anonymous functions

	   Described in perlreftut, perlref, perldsc, and perllol.

       o   object-oriented programming

	   Described in perlobj and perlootut.

       o   support for light-weight processes (threads)

	   Described in perlthrtut and threads.

       o   support for Unicode, internationalization, and localization

	   Described in perluniintro, perllocale and Locale::Maketext.

       o   lexical scoping

	   Described in perlsub.

       o   regular expression enhancements

	   Described in perlre, with additional examples in perlop.

       o   enhanced debugger and interactive Perl environment, with integrated
	   editor support

	   Described in perldebtut, perldebug and perldebguts.

       o   POSIX 1003.1 compliant library

	   Described in POSIX.

       Okay, that's definitely enough hype.

AVAILABILITY
       Perl is available for most operating systems, including virtually all
       Unix-like platforms.  See "Supported Platforms" 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'Reilly)
	http://www.cpan.org/	   the Comprehensive Perl Archive
	http://www.pm.org/	   the Perl Mongers

DIAGNOSTICS
       The "use warnings" pragma (and the -w switch) produces some lovely
       diagnostics.

       See perldiag for explanations of all Perl's diagnostics.	 The "use
       diagnostics" 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 "Insecure dependency".	See perlsec.

       Did we mention that you should definitely consider using the -w switch?

BUGS
       The -w switch 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 "perl -V") 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 "There's more than one way to do it."	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.



perl v5.16.3			  2013-03-04			       PERL(1)