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Reference
ActivePerl 5.10
Welcome to ActivePerl
Getting Started
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perl
perlintro
perltoc
perlreftut
perldsc
perllol
perlrequick
perlretut
perlboot
perltoot
perltooc
perlbot
perlstyle
perlcheat
perltrap
perldebtut
perlfaq
perlfaq1
perlfaq2
perlfaq3
perlfaq4
perlfaq5
perlfaq6
perlfaq7
perlfaq8
perlfaq9
perlsyn
perldata
perlop
perlsub
perlfunc
perlopentut
perlpacktut
perlpod
perlpodspec
perlrun
perldiag
perllexwarn
perldebug
perlvar
perlre
perlrebackslash
perlrecharclass
perlreref
perlref
perlform
perlobj
perltie
perldbmfilter
perlipc
perlfork
perlnumber
perlthrtut
perlothrtut
perlport
perllocale
perluniintro
perlunicode
perlunifaq
perlunitut
perlebcdic
perlsec
perlmod
perlmodlib
perlmodstyle
perlmodinstall
perlnewmod
perlpragma
perlutil
perlcompile
perlfilter
perlglossary
perlembed
perldebguts
perlxstut
perlxs
perlclib
perlguts
perlcall
perlreapi
perlreguts
perlapi
perlintern
perliol
perlapio
perlhack
perlbook
perlcommunity
perltodo
perldoc
perlhist
perldelta
perl5100delta
perl595delta
perl594delta
perl593delta
perl592delta
perl591delta
perl590delta
perl588delta
perl587delta
perl586delta
perl585delta
perl584delta
perl583delta
perl582delta
perl581delta
perl58delta
perl573delta
perl572delta
perl571delta
perl570delta
perl561delta
perl56delta
perl5005delta
perl5004delta
perlartistic
perlgpl
perlcn
perljp
perlko
perltw
perlaix
perlamiga
perlapollo
perlbeos
perlbs2000
perlce
perlcygwin
perldgux
perldos
perlepoc
perlfreebsd
perlhpux
perlhurd
perlirix
perllinux
perlmachten
perlmacos
perlmacosx
perlmint
perlmpeix
perlnetware
perlopenbsd
perlos2
perlos390
perlos400
perlplan9
perlqnx
perlriscos
perlsolaris
perlsymbian
perltru64
perluts
perlvmesa
perlvms
perlvos
perlwin32
Programs
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MyASPN >> Reference >> ActivePerl 5.10
ActivePerl 5.10 documentation

NAME

perl - Practical Extraction and Report Language


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]
-P ]
-S ]
-x[dir] ]
-i[extension] ]
-e 'command' ] [ -- ] [ programfile ] [ argument ]...

If you're new to Perl, you should start with the perlintro manpage, which is a general intro for beginners and provides some background to help you navigate the rest of Perl's extensive documentation.

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
    ActivePerl          ActivePerl overview

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
    perlboot            Perl OO tutorial for beginners
    perltoot            Perl OO tutorial, part 1
    perltooc            Perl OO tutorial, part 2
    perlbot             Perl OO tricks and examples
    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
    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
      perlothrtut       Old Perl threads tutorial
    perlport            Perl portability guide
    perllocale          Perl locale support
    perluniintro        Perl Unicode introduction
    perlunicode         Perl Unicode support
    perlunifaq          Perl Unicode FAQ
    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
    perlcompile         Perl compiler suite intro
    perlfilter          Perl source filters
    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
    perlclib            Internal replacements for standard C library functions
    perlguts            Perl internal functions for those doing extensions
    perlcall            Perl calling conventions from C
    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

Miscellaneous

    perlbook            Perl book information
    perlcommunity       Perl community information
    perltodo            Perl things to do
    perldoc             Look up Perl documentation in Pod format
    perlhist            Perl history records
    perldelta           Perl changes since previous version
    perl595delta        Perl changes in version 5.9.5
    perl594delta        Perl changes in version 5.9.4
    perl593delta        Perl changes in version 5.9.3
    perl592delta        Perl changes in version 5.9.2
    perl591delta        Perl changes in version 5.9.1
    perl590delta        Perl changes in version 5.9.0
    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
    perl573delta        Perl changes in version 5.7.3
    perl572delta        Perl changes in version 5.7.2
    perl571delta        Perl changes in version 5.7.1
    perl570delta        Perl changes in version 5.7.0
    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
    activeperl-release  Release notes for ActivePerl
    activeperl-changes  ActivePerl revision history
    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
    perlapollo          Perl notes for Apollo DomainOS
    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
    perlhpux            Perl notes for HP-UX
    perlhurd            Perl notes for Hurd
    perlirix            Perl notes for Irix
    perllinux           Perl notes for Linux
    perlmachten         Perl notes for Power MachTen
    perlmacos           Perl notes for Mac OS (Classic)
    perlmacosx          Perl notes for Mac OS X
    perlmint            Perl notes for MiNT
    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

By default, the manpages listed above are installed in the /usr/local/man/ directory.

Extensive additional documentation for Perl modules is available. The default configuration for perl will place this additional documentation in the /usr/local/lib/perl5/man directory (or else in the 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 have a common stem, such as /usr/local/man/man1 and /usr/local/man/man3, you need only to add that stem (/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 perldoc script to view module information. You might also look into getting a replacement man program.

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 is a language optimized for scanning arbitrary text files, extracting information from those text files, and printing reports based on that information. It's also a good language for many system management tasks. 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 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 that prevents many stupid security holes.

If you have a problem that would ordinarily use sed or awk or 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 sed and awk scripts into Perl scripts.

But wait, there's more...

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