PERL(1) Perl Programmers Reference Guide PERL(1) #
PERL(1) Perl Programmers Reference Guide PERL(1)
NNAAMMEE #
perl - The Perl 5 language interpreter
SSYYNNOOPPSSIISS #
ppeerrll [ --ssTTttuuUUWWXX ] [ --hhvv ] [ --VV[:_c_o_n_f_i_g_v_a_r] ]
[ --ccww ] [ --dd[tt][:_d_e_b_u_g_g_e_r] ] [ --DD[_n_u_m_b_e_r_/_l_i_s_t] ]
[ --ppnnaa ] [ --FF_p_a_t_t_e_r_n ] [ --ll[_o_c_t_a_l] ] [ --00[_o_c_t_a_l_/_h_e_x_a_d_e_c_i_m_a_l] ]
[ --II_d_i_r ] [ --mm[--]_m_o_d_u_l_e ] [ --MM[--]_'_m_o_d_u_l_e_._._._' ] [ --ff ]
[ --CC [[_nn_uu_mm_bb_ee_rr_//_ll_ii_ss_tt]] ] [ --SS ] [ --xx[_d_i_r] ] [ --ii[_e_x_t_e_n_s_i_o_n] ]
[ [--ee|--EE] _'_c_o_m_m_a_n_d_' ] [ ---- ] [ _p_r_o_g_r_a_m_f_i_l_e ] [ _a_r_g_u_m_e_n_t ]...
For more information on these options, you can run "perldoc perlrun".
GGEETTTTIINNGG HHEELLPP #
The _p_e_r_l_d_o_c program gives you access to all the documentation that comes
with Perl. You can get more documentation, tutorials and community
support online at <https://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 _p_e_r_l_d_o_c.
For ease of access, the Perl manual has been split up into several
sections.
OOvveerrvviieeww perl Perl overview (this section) perlintro Perl introduction for beginners perlrun Perl execution and options perltoc Perl documentation table of contents
TTuuttoorriiaallss 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
RReeffeerreennccee MMaannuuaall 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 perldocstyle Perl style guide for core docs perlpodstyle Perl POD style guide perldiag Perl diagnostic messages perldeprecation Perl deprecations 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
perlsecpolicy Perl security report handling policy
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
IInntteerrnnaallss aanndd CC LLaanngguuaaggee IInntteerrffaaccee 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
perlgov Perl Rules of Governance
perlgit Using git with the Perl repository
HHiissttoorryy perlhist Perl history records perldelta Perl changes since previous version perl5362delta Perl changes in version 5.36.2 perl5361delta Perl changes in version 5.36.1 perl5360delta Perl changes in version 5.36.0 perl5343delta Perl changes in version 5.34.3 perl5342delta Perl changes in version 5.34.2 perl5341delta Perl changes in version 5.34.1 perl5340delta Perl changes in version 5.34.0 perl5321delta Perl changes in version 5.32.1 perl5320delta Perl changes in version 5.32.0 perl5303delta Perl changes in version 5.30.3 perl5302delta Perl changes in version 5.30.2 perl5301delta Perl changes in version 5.30.1 perl5300delta Perl changes in version 5.30.0 perl5283delta Perl changes in version 5.28.3 perl5282delta Perl changes in version 5.28.2 perl5281delta Perl changes in version 5.28.1 perl5280delta Perl changes in version 5.28.0 perl5263delta Perl changes in version 5.26.3 perl5262delta Perl changes in version 5.26.2 perl5261delta Perl changes in version 5.26.1 perl5260delta Perl changes in version 5.26.0 perl5244delta Perl changes in version 5.24.4 perl5243delta Perl changes in version 5.24.3 perl5242delta Perl changes in version 5.24.2 perl5241delta Perl changes in version 5.24.1 perl5240delta Perl changes in version 5.24.0 perl5224delta Perl changes in version 5.22.4 perl5223delta Perl changes in version 5.22.3 perl5222delta Perl changes in version 5.22.2 perl5221delta Perl changes in version 5.22.1 perl5220delta Perl changes in version 5.22.0 perl5203delta Perl changes in version 5.20.3 perl5202delta Perl changes in version 5.20.2 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
MMiisscceellllaanneeoouuss perlbook Perl book information perlcommunity Perl community information
perldoc Look up Perl documentation in Pod format
perlexperiment A listing of experimental features in Perl
perlartistic Perl Artistic License
perlgpl GNU General Public License
LLaanngguuaaggee--SSppeecciiffiicc perlcn Perl for Simplified Chinese (in UTF-8) perljp Perl for Japanese (in EUC-JP) perlko Perl for Korean (in EUC-KR) perltw Perl for Traditional Chinese (in Big5)
PPllaattffoorrmm--SSppeecciiffiicc perlaix Perl notes for AIX perlamiga Perl notes for AmigaOS perlandroid Perl notes for Android perlbs2000 Perl notes for POSIX-BC BS2000 perlcygwin Perl notes for Cygwin 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 perlmacosx Perl notes for Mac OS X 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 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
SSttuubbss ffoorr DDeelleetteedd DDooccuummeennttss perlboot perlbot perlrepository perltodo perltooc perltoot
On a Unix-like system, these documentation files will usually also be
available as manpages for use with the _m_a_n program.
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 --ff 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 uussee ssttrriicctt and uussee wwaarrnniinnggss. These will often point out
exactly where the trouble is.
DDEESSCCRRIIPPTTIIOONN #
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 sseedd, aawwkk,
and sshh, 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.
AAVVAAIILLAABBIILLIITTYY #
Perl is available for most operating systems, including virtually all
Unix-like platforms. See "Supported Platforms" in perlport for a
listing.
EENNVVIIRROONNMMEENNTT #
See "ENVIRONMENT" in perlrun.
AAUUTTHHOORR #
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 .
FFIILLEESS #
"@INC" locations of perl libraries
"@INC" above is a reference to the built-in variable of the same name;
see perlvar for more information.
SSEEEE AALLSSOO #
https://www.perl.org/ the Perl homepage
https://www.perl.com/ Perl articles
https://www.cpan.org/ the Comprehensive Perl Archive
https://www.pm.org/ the Perl Mongers
DDIIAAGGNNOOSSTTIICCSS #
Using the "use strict" pragma ensures that all variables are properly
declared and prevents other misuses of legacy Perl features. These are
enabled by default within the scope of "use v5.12" (or higher).
The "use warnings" pragma produces some lovely diagnostics. It is
enabled by default when you say "use v5.35" (or higher). One can also
use the --ww 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 --ee switches, each --ee 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 uussee wwaarrnniinnggss
pragma?
BBUUGGSS #
The behavior implied by the uussee wwaarrnniinnggss pragma is not mandatory.
Perl is at the mercy of your machine's definitions of various operations
such as type casting, aattooff(()), and floating-point output with sspprriinnttff(()).
If your stdio requires a seek or eof between reads and writes on a
particular stream, so does Perl. (This doesn't apply to ssyyssrreeaadd(()) and
ssyysswwrriittee(()).)
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 submit 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 <https://github.com/Perl/perl5/issues>.
Perl actually stands for Pathologically Eclectic Rubbish Lister, but
don't tell anyone I said that.
NNOOTTEESS #
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 v5.36.3 2023-12-23 PERL(1)