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 ]...
For more information on these options, you can run "perldoc perlrun".
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 beginnersperlrun Perl execution and optionsperltoc Perl documentation table of contents
Tutorials
perlreftut Perl references short introductionperldsc Perl data structures introperllol Perl data structures: arrays of arraysperlrequick Perl regular expressions quick startperlretut Perl regular expressions tutorialperlootut Perl OO tutorial for beginnersperlperf Perl Performance and Optimization Techniquesperlstyle Perl style guideperlcheat Perl cheat sheetperltrap Perl traps for the unwaryperldebtut Perl debugging tutorialperlfaq Perl frequently asked questionsperlfaq1 General Questions About Perlperlfaq2 Obtaining and Learning about Perlperlfaq3 Programming Toolsperlfaq4 Data Manipulationperlfaq5 Files and Formatsperlfaq6 Regexesperlfaq7 Perl Language Issuesperlfaq8 System Interactionperlfaq9 Networking
Reference Manual
perlsyn Perl syntaxperldata Perl data structuresperlop Perl operators and precedenceperlsub Perl subroutinesperlfunc Perl built-in functionsperlopentut Perl open() tutorialperlpacktut Perl pack() and unpack() tutorialperlpod Perl plain old documentationperlpodspec Perl plain old documentation format specificationperlpodstyle Perl POD style guideperldiag Perl diagnostic messagesperllexwarn Perl warnings and their controlperldebug Perl debuggingperlvar Perl predefined variablesperlre Perl regular expressions, the rest of the storyperlrebackslash Perl regular expression backslash sequencesperlrecharclass Perl regular expression character classesperlreref Perl regular expressions quick referenceperlref Perl references, the rest of the storyperlform Perl formatsperlobj Perl objectsperltie Perl objects hidden behind simple variablesperldbmfilter Perl DBM filtersperlipc Perl interprocess communicationperlfork Perl fork() informationperlnumber Perl number semanticsperlthrtut Perl threads tutorialperlport Perl portability guideperllocale Perl locale supportperluniintro Perl Unicode introductionperlunicode Perl Unicode supportperlunicook Perl Unicode cookbookperlunifaq Perl Unicode FAQperluniprops Index of Unicode properties in Perlperlunitut Perl Unicode tutorialperlebcdic Considerations for running Perl on EBCDIC platformsperlsec Perl securityperlmod Perl modules: how they workperlmodlib Perl modules: how to write and useperlmodstyle Perl modules: how to write modules with styleperlmodinstall Perl modules: how to install from CPANperlnewmod Perl modules: preparing a new module for distributionperlpragma Perl modules: writing a user pragmaperlutil utilities packaged with the Perl distributionperlfilter Perl source filtersperldtrace Perl's support for DTraceperlglossary Perl Glossary
Internals and C Language Interface
perlembed Perl ways to embed perl in your C or C++ applicationperldebguts Perl debugging guts and tipsperlxstut Perl XS tutorialperlxs Perl XS application programming interfaceperlxstypemap Perl XS C/Perl type conversion toolsperlclib Internal replacements for standard C library functionsperlguts Perl internal functions for those doing extensionsperlcall Perl calling conventions from Cperlmroapi Perl method resolution plugin interfaceperlreapi Perl regular expression plugin interfaceperlreguts Perl regular expression engine internalsperlapi Perl API listing (autogenerated)perlintern Perl internal functions (autogenerated)perliol C API for Perl's implementation of IO in Layersperlapio Perl internal IO abstraction interfaceperlhack Perl hackers guideperlsource Guide to the Perl source treeperlinterp Overview of the Perl interpreter source and how it worksperlhacktut Walk through the creation of a simple C code patchperlhacktips Tips for Perl core C code hackingperlpolicy Perl development policiesperlgit Using git with the Perl repository
Miscellaneous
perlbook Perl book informationperlcommunity Perl community informationperldoc Look up Perl documentation in Pod formatperlhist Perl history recordsperldelta Perl changes since previous versionperl5240delta Perl changes in version 5.24.0perl5222delta Perl changes in version 5.22.2perl5221delta Perl changes in version 5.22.1perl5220delta Perl changes in version 5.22.0perl5203delta Perl changes in version 5.20.3perl5202delta Perl changes in version 5.20.2perl5201delta Perl changes in version 5.20.1perl5200delta Perl changes in version 5.20.0perl5184delta Perl changes in version 5.18.4perl5182delta Perl changes in version 5.18.2perl5181delta Perl changes in version 5.18.1perl5180delta Perl changes in version 5.18.0perl5163delta Perl changes in version 5.16.3perl5162delta Perl changes in version 5.16.2perl5161delta Perl changes in version 5.16.1perl5160delta Perl changes in version 5.16.0perl5144delta Perl changes in version 5.14.4perl5143delta Perl changes in version 5.14.3perl5142delta Perl changes in version 5.14.2perl5141delta Perl changes in version 5.14.1perl5140delta Perl changes in version 5.14.0perl5125delta Perl changes in version 5.12.5perl5124delta Perl changes in version 5.12.4perl5123delta Perl changes in version 5.12.3perl5122delta Perl changes in version 5.12.2perl5121delta Perl changes in version 5.12.1perl5120delta Perl changes in version 5.12.0perl5101delta Perl changes in version 5.10.1perl5100delta Perl changes in version 5.10.0perl589delta Perl changes in version 5.8.9perl588delta Perl changes in version 5.8.8perl587delta Perl changes in version 5.8.7perl586delta Perl changes in version 5.8.6perl585delta Perl changes in version 5.8.5perl584delta Perl changes in version 5.8.4perl583delta Perl changes in version 5.8.3perl582delta Perl changes in version 5.8.2perl581delta Perl changes in version 5.8.1perl58delta Perl changes in version 5.8.0perl561delta Perl changes in version 5.6.1perl56delta Perl changes in version 5.6perl5005delta Perl changes in version 5.005perl5004delta Perl changes in version 5.004perlexperiment A listing of experimental features in Perlperlartistic Perl Artistic Licenseperlgpl 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 AIXperlamiga Perl notes for AmigaOSperlandroid Perl notes for Androidperlbs2000 Perl notes for POSIX-BC BS2000perlce Perl notes for WinCEperlcygwin Perl notes for Cygwinperldos Perl notes for DOSperlfreebsd Perl notes for FreeBSDperlhaiku Perl notes for Haikuperlhpux Perl notes for HP-UXperlhurd Perl notes for Hurdperlirix Perl notes for Irixperllinux Perl notes for Linuxperlmacos Perl notes for Mac OS (Classic)perlmacosx Perl notes for Mac OS Xperlnetware Perl notes for NetWareperlopenbsd Perl notes for OpenBSDperlos2 Perl notes for OS/2perlos390 Perl notes for OS/390perlos400 Perl notes for OS/400perlplan9 Perl notes for Plan 9perlqnx Perl notes for QNXperlriscos Perl notes for RISC OSperlsolaris Perl notes for Solarisperlsymbian Perl notes for Symbianperlsynology Perl notes for Synologyperltru64 Perl notes for Tru64perlvms Perl notes for VMSperlvos Perl notes for Stratus VOSperlwin32 Perl notes for Windows
Stubs for Deleted Documents
perlbootperlbotperlrepositoryperltodoperltoocperltoot
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 "perldoc --help" (or "perldoc perldoc" or "man perldoc") 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 "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). 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 CPAN, 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 "Supported Platforms" in perlport for a listing.
ENVIRONMENT
See perlrun.
AUTHOR
Larry Wall <[email protected]>, 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 [email protected] .
FILES
"@INC" locations of perl libraries
"@INC" above is a reference to the built-in variable of the same name; see perlvar for more information.
SEE ALSO
http://www.perl.org/ the Perl homepagehttp://www.perl.com/ Perl articles (O'Reilly)http://www.cpan.org/ the Comprehensive Perl Archivehttp://www.pm.org/ the Perl Mongers
DIAGNOSTICS
Using the "use strict" pragma ensures that all variables are properly declared and prevents other misuses of legacy Perl features.
The "use warnings" 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 "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 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 "perl -V") to [email protected] . 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.