NAME

perl - Practical Extraction and Report Language

perl [ -sTuU ] [ -hv ] [ -V[:configvar] ] [ -cw ] [ -d[:debugger] ] [ -D[number/list] ] [ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal] ] [ -Idir ] [ -m[-]module ] [ -M[-]'module...' ] [ -P ] [ -S ] [ -x[dir] ] [ -i[extension] ] [ -e 'command' ] [ -- ] [ programfile ] [ argument ]...

If you're new to Perl, you should start with perlintro, 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

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 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 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 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 perlutil utilities packaged with the Perl distribution perlcompile Perl compiler suite intro perlfilter Perl source filters

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 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 perltodo Perl things to do perlhist Perl history records perldelta Perl changes since previous version 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

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 perlmachten Perl notes for Power MachTen perlmacos Perl notes for Mac OS (Classic) perlmint Perl notes for MiNT perlmpeix Perl notes for MPE/iX perlnetware Perl notes for NetWare perlos2 Perl notes for OS/2 perlos390 Perl notes for OS/390 perlplan9 Perl notes for Plan 9 perlqnx Perl notes for QNX perlsolaris Perl notes for Solaris 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 perlhist), Perl version 5 is nearly a complete rewrite that provides the following additional benefits:

modularity and reusability using innumerable modules

Described in perlmod, perlmodlib, and perlmodinstall.
embeddable and extensible

Described in perlembed, perlxstut, perlxs, perlcall, perlguts, and xsubpp.
roll-your-own magic variables (including multiple simultaneous DBM implementations)

Described in perltie and AnyDBM_File.
subroutines can now be overridden, autoloaded, and prototyped

Described in perlsub.
arbitrarily nested data structures and anonymous functions

Described in perlreftut, perlref, perldsc, and perllol.
object-oriented programming

Described in perlobj, perlboot, perltoot, perltooc, and perlbot.
compilability into C code or Perl bytecode

Described in B and B::Bytecode.
support for light-weight processes (threads)

Described in perlthrtut and Thread.
support for internationalization, localization, and Unicode

Described in perllocale and utf8.
lexical scoping

Described in perlsub.
regular expression enhancements

Described in perlre, with additional examples in perlop.
enhanced debugger and interactive Perl environment, with integrated editor support

Described in perldebtut, perldebug and perldebguts.
POSIX 1003.1 compliant library

Described in POSIX.

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