1PERL(1)                Perl Programmers Reference Guide                PERL(1)
2
3
4

NAME

6       perl - The Perl 5 language interpreter
7

SYNOPSIS

9       perl [ -sTtuUWX ]      [ -hv ] [ -V[:configvar] ]
10            [ -cw ] [ -d[t][:debugger] ] [ -D[number/list] ]
11            [ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal/hexadecimal] ]
12            [ -Idir ] [ -m[-]module ] [ -M[-]'module...' ] [ -f ]
13            [ -C [number/list] ]      [ -S ]      [ -x[dir] ]
14            [ -i[extension] ]
15            [ [-e|-E] 'command' ] [ -- ] [ programfile ] [ argument ]...
16
17       For more information on these options, you can run "perldoc perlrun".
18

GETTING HELP

20       The perldoc program gives you access to all the documentation that
21       comes with Perl.  You can get more documentation, tutorials and
22       community support online at <https://www.perl.org/>.
23
24       If you're new to Perl, you should start by running "perldoc perlintro",
25       which is a general intro for beginners and provides some background to
26       help you navigate the rest of Perl's extensive documentation.  Run
27       "perldoc perldoc" to learn more things you can do with perldoc.
28
29       For ease of access, the Perl manual has been split up into several
30       sections.
31
32   Overview
33           perl                Perl overview (this section)
34           perlintro           Perl introduction for beginners
35           perlrun             Perl execution and options
36           perltoc             Perl documentation table of contents
37
38   Tutorials
39           perlreftut          Perl references short introduction
40           perldsc             Perl data structures intro
41           perllol             Perl data structures: arrays of arrays
42
43           perlrequick         Perl regular expressions quick start
44           perlretut           Perl regular expressions tutorial
45
46           perlootut           Perl OO tutorial for beginners
47
48           perlperf            Perl Performance and Optimization Techniques
49
50           perlstyle           Perl style guide
51
52           perlcheat           Perl cheat sheet
53           perltrap            Perl traps for the unwary
54           perldebtut          Perl debugging tutorial
55
56           perlfaq             Perl frequently asked questions
57             perlfaq1          General Questions About Perl
58             perlfaq2          Obtaining and Learning about Perl
59             perlfaq3          Programming Tools
60             perlfaq4          Data Manipulation
61             perlfaq5          Files and Formats
62             perlfaq6          Regexes
63             perlfaq7          Perl Language Issues
64             perlfaq8          System Interaction
65             perlfaq9          Networking
66
67   Reference Manual
68           perlsyn             Perl syntax
69           perldata            Perl data structures
70           perlop              Perl operators and precedence
71           perlsub             Perl subroutines
72           perlfunc            Perl built-in functions
73             perlopentut       Perl open() tutorial
74             perlpacktut       Perl pack() and unpack() tutorial
75           perlpod             Perl plain old documentation
76           perlpodspec         Perl plain old documentation format specification
77           perlpodstyle        Perl POD style guide
78           perldiag            Perl diagnostic messages
79           perldeprecation     Perl deprecations
80           perllexwarn         Perl warnings and their control
81           perldebug           Perl debugging
82           perlvar             Perl predefined variables
83           perlre              Perl regular expressions, the rest of the story
84           perlrebackslash     Perl regular expression backslash sequences
85           perlrecharclass     Perl regular expression character classes
86           perlreref           Perl regular expressions quick reference
87           perlref             Perl references, the rest of the story
88           perlform            Perl formats
89           perlobj             Perl objects
90           perltie             Perl objects hidden behind simple variables
91             perldbmfilter     Perl DBM filters
92
93           perlipc             Perl interprocess communication
94           perlfork            Perl fork() information
95           perlnumber          Perl number semantics
96
97           perlthrtut          Perl threads tutorial
98
99           perlport            Perl portability guide
100           perllocale          Perl locale support
101           perluniintro        Perl Unicode introduction
102           perlunicode         Perl Unicode support
103           perlunicook         Perl Unicode cookbook
104           perlunifaq          Perl Unicode FAQ
105           perluniprops        Index of Unicode properties in Perl
106           perlunitut          Perl Unicode tutorial
107           perlebcdic          Considerations for running Perl on EBCDIC platforms
108
109           perlsec             Perl security
110           perlsecpolicy       Perl security report handling policy
111
112           perlmod             Perl modules: how they work
113           perlmodlib          Perl modules: how to write and use
114           perlmodstyle        Perl modules: how to write modules with style
115           perlmodinstall      Perl modules: how to install from CPAN
116           perlnewmod          Perl modules: preparing a new module for distribution
117           perlpragma          Perl modules: writing a user pragma
118
119           perlutil            utilities packaged with the Perl distribution
120
121           perlfilter          Perl source filters
122
123           perldtrace          Perl's support for DTrace
124
125           perlglossary        Perl Glossary
126
127   Internals and C Language Interface
128           perlembed           Perl ways to embed perl in your C or C++ application
129           perldebguts         Perl debugging guts and tips
130           perlxstut           Perl XS tutorial
131           perlxs              Perl XS application programming interface
132           perlxstypemap       Perl XS C/Perl type conversion tools
133           perlclib            Internal replacements for standard C library functions
134           perlguts            Perl internal functions for those doing extensions
135           perlcall            Perl calling conventions from C
136           perlmroapi          Perl method resolution plugin interface
137           perlreapi           Perl regular expression plugin interface
138           perlreguts          Perl regular expression engine internals
139
140           perlapi             Perl API listing (autogenerated)
141           perlintern          Perl internal functions (autogenerated)
142           perliol             C API for Perl's implementation of IO in Layers
143           perlapio            Perl internal IO abstraction interface
144
145           perlhack            Perl hackers guide
146           perlsource          Guide to the Perl source tree
147           perlinterp          Overview of the Perl interpreter source and how it works
148           perlhacktut         Walk through the creation of a simple C code patch
149           perlhacktips        Tips for Perl core C code hacking
150           perlpolicy          Perl development policies
151           perlgov             Perl Rules of Governance
152           perlgit             Using git with the Perl repository
153
154   Miscellaneous
155           perlbook            Perl book information
156           perlcommunity       Perl community information
157
158           perldoc             Look up Perl documentation in Pod format
159
160           perlhist            Perl history records
161           perldelta           Perl changes since previous version
162           perl5320delta       Perl changes in version 5.32.0
163           perl5303delta       Perl changes in version 5.30.3
164           perl5302delta       Perl changes in version 5.30.2
165           perl5301delta       Perl changes in version 5.30.1
166           perl5300delta       Perl changes in version 5.30.0
167           perl5283delta       Perl changes in version 5.28.3
168           perl5282delta       Perl changes in version 5.28.2
169           perl5281delta       Perl changes in version 5.28.1
170           perl5280delta       Perl changes in version 5.28.0
171           perl5263delta       Perl changes in version 5.26.3
172           perl5262delta       Perl changes in version 5.26.2
173           perl5261delta       Perl changes in version 5.26.1
174           perl5260delta       Perl changes in version 5.26.0
175           perl5244delta       Perl changes in version 5.24.4
176           perl5243delta       Perl changes in version 5.24.3
177           perl5242delta       Perl changes in version 5.24.2
178           perl5241delta       Perl changes in version 5.24.1
179           perl5240delta       Perl changes in version 5.24.0
180           perl5224delta       Perl changes in version 5.22.4
181           perl5223delta       Perl changes in version 5.22.3
182           perl5222delta       Perl changes in version 5.22.2
183           perl5221delta       Perl changes in version 5.22.1
184           perl5220delta       Perl changes in version 5.22.0
185           perl5203delta       Perl changes in version 5.20.3
186           perl5202delta       Perl changes in version 5.20.2
187           perl5201delta       Perl changes in version 5.20.1
188           perl5200delta       Perl changes in version 5.20.0
189           perl5184delta       Perl changes in version 5.18.4
190           perl5182delta       Perl changes in version 5.18.2
191           perl5181delta       Perl changes in version 5.18.1
192           perl5180delta       Perl changes in version 5.18.0
193           perl5163delta       Perl changes in version 5.16.3
194           perl5162delta       Perl changes in version 5.16.2
195           perl5161delta       Perl changes in version 5.16.1
196           perl5160delta       Perl changes in version 5.16.0
197           perl5144delta       Perl changes in version 5.14.4
198           perl5143delta       Perl changes in version 5.14.3
199           perl5142delta       Perl changes in version 5.14.2
200           perl5141delta       Perl changes in version 5.14.1
201           perl5140delta       Perl changes in version 5.14.0
202           perl5125delta       Perl changes in version 5.12.5
203           perl5124delta       Perl changes in version 5.12.4
204           perl5123delta       Perl changes in version 5.12.3
205           perl5122delta       Perl changes in version 5.12.2
206           perl5121delta       Perl changes in version 5.12.1
207           perl5120delta       Perl changes in version 5.12.0
208           perl5101delta       Perl changes in version 5.10.1
209           perl5100delta       Perl changes in version 5.10.0
210           perl589delta        Perl changes in version 5.8.9
211           perl588delta        Perl changes in version 5.8.8
212           perl587delta        Perl changes in version 5.8.7
213           perl586delta        Perl changes in version 5.8.6
214           perl585delta        Perl changes in version 5.8.5
215           perl584delta        Perl changes in version 5.8.4
216           perl583delta        Perl changes in version 5.8.3
217           perl582delta        Perl changes in version 5.8.2
218           perl581delta        Perl changes in version 5.8.1
219           perl58delta         Perl changes in version 5.8.0
220           perl561delta        Perl changes in version 5.6.1
221           perl56delta         Perl changes in version 5.6
222           perl5005delta       Perl changes in version 5.005
223           perl5004delta       Perl changes in version 5.004
224
225           perlexperiment      A listing of experimental features in Perl
226
227           perlartistic        Perl Artistic License
228           perlgpl             GNU General Public License
229
230   Language-Specific
231           perlcn              Perl for Simplified Chinese (in EUC-CN)
232           perljp              Perl for Japanese (in EUC-JP)
233           perlko              Perl for Korean (in EUC-KR)
234           perltw              Perl for Traditional Chinese (in Big5)
235
236   Platform-Specific
237           perlaix             Perl notes for AIX
238           perlamiga           Perl notes for AmigaOS
239           perlandroid         Perl notes for Android
240           perlbs2000          Perl notes for POSIX-BC BS2000
241           perlcygwin          Perl notes for Cygwin
242           perldos             Perl notes for DOS
243           perlfreebsd         Perl notes for FreeBSD
244           perlhaiku           Perl notes for Haiku
245           perlhpux            Perl notes for HP-UX
246           perlhurd            Perl notes for Hurd
247           perlirix            Perl notes for Irix
248           perllinux           Perl notes for Linux
249           perlmacos           Perl notes for Mac OS (Classic)
250           perlmacosx          Perl notes for Mac OS X
251           perlnetware         Perl notes for NetWare
252           perlopenbsd         Perl notes for OpenBSD
253           perlos2             Perl notes for OS/2
254           perlos390           Perl notes for OS/390
255           perlos400           Perl notes for OS/400
256           perlplan9           Perl notes for Plan 9
257           perlqnx             Perl notes for QNX
258           perlriscos          Perl notes for RISC OS
259           perlsolaris         Perl notes for Solaris
260           perlsymbian         Perl notes for Symbian
261           perlsynology        Perl notes for Synology
262           perltru64           Perl notes for Tru64
263           perlvms             Perl notes for VMS
264           perlvos             Perl notes for Stratus VOS
265           perlwin32           Perl notes for Windows
266
267   Stubs for Deleted Documents
268           perlboot
269           perlbot
270           perlrepository
271           perltodo
272           perltooc
273           perltoot
274
275       On a Unix-like system, these documentation files will usually also be
276       available as manpages for use with the man program.
277
278       Some documentation is not available as man pages, so if a cross-
279       reference is not found by man, try it with perldoc.  Perldoc can also
280       take you directly to documentation for functions (with the -f switch).
281       See "perldoc --help" (or "perldoc perldoc" or "man perldoc") for other
282       helpful options perldoc has to offer.
283
284       In general, if something strange has gone wrong with your program and
285       you're not sure where you should look for help, try making your code
286       comply with use strict and use warnings.  These will often point out
287       exactly where the trouble is.
288

DESCRIPTION

290       Perl officially stands for Practical Extraction and Report Language,
291       except when it doesn't.
292
293       Perl was originally a language optimized for scanning arbitrary text
294       files, extracting information from those text files, and printing
295       reports based on that information.  It quickly became a good language
296       for many system management tasks. Over the years, Perl has grown into a
297       general-purpose programming language. It's widely used for everything
298       from quick "one-liners" to full-scale application development.
299
300       The language is intended to be practical (easy to use, efficient,
301       complete) rather than beautiful (tiny, elegant, minimal).  It combines
302       (in the author's opinion, anyway) some of the best features of sed,
303       awk, and sh, making it familiar and easy to use for Unix users to whip
304       up quick solutions to annoying problems.  Its general-purpose
305       programming facilities support procedural, functional, and object-
306       oriented programming paradigms, making Perl a comfortable language for
307       the long haul on major projects, whatever your bent.
308
309       Perl's roots in text processing haven't been forgotten over the years.
310       It still boasts some of the most powerful regular expressions to be
311       found anywhere, and its support for Unicode text is world-class.  It
312       handles all kinds of structured text, too, through an extensive
313       collection of extensions.  Those libraries, collected in the CPAN,
314       provide ready-made solutions to an astounding array of problems.  When
315       they haven't set the standard themselves, they steal from the best --
316       just like Perl itself.
317

AVAILABILITY

319       Perl is available for most operating systems, including virtually all
320       Unix-like platforms.  See "Supported Platforms" in perlport for a
321       listing.
322

ENVIRONMENT

324       See "ENVIRONMENT" in perlrun.
325

AUTHOR

327       Larry Wall <larry@wall.org>, with the help of oodles of other folks.
328
329       If your Perl success stories and testimonials may be of help to others
330       who wish to advocate the use of Perl in their applications, or if you
331       wish to simply express your gratitude to Larry and the Perl developers,
332       please write to perl-thanks@perl.org .
333

FILES

335        "@INC"                 locations of perl libraries
336
337       "@INC" above is a reference to the built-in variable of the same name;
338       see perlvar for more information.
339

SEE ALSO

341        https://www.perl.org/       the Perl homepage
342        https://www.perl.com/       Perl articles
343        https://www.cpan.org/       the Comprehensive Perl Archive
344        https://www.pm.org/         the Perl Mongers
345

DIAGNOSTICS

347       Using the "use strict" pragma ensures that all variables are properly
348       declared and prevents other misuses of legacy Perl features.
349
350       The "use warnings" pragma produces some lovely diagnostics. One can
351       also use the -w flag, but its use is normally discouraged, because it
352       gets applied to all executed Perl code, including that not under your
353       control.
354
355       See perldiag for explanations of all Perl's diagnostics.  The "use
356       diagnostics" pragma automatically turns Perl's normally terse warnings
357       and errors into these longer forms.
358
359       Compilation errors will tell you the line number of the error, with an
360       indication of the next token or token type that was to be examined.
361       (In a script passed to Perl via -e switches, each -e is counted as one
362       line.)
363
364       Setuid scripts have additional constraints that can produce error
365       messages such as "Insecure dependency".  See perlsec.
366
367       Did we mention that you should definitely consider using the use
368       warnings pragma?
369

BUGS

371       The behavior implied by the use warnings pragma is not mandatory.
372
373       Perl is at the mercy of your machine's definitions of various
374       operations such as type casting, atof(), and floating-point output with
375       sprintf().
376
377       If your stdio requires a seek or eof between reads and writes on a
378       particular stream, so does Perl.  (This doesn't apply to sysread() and
379       syswrite().)
380
381       While none of the built-in data types have any arbitrary size limits
382       (apart from memory size), there are still a few arbitrary limits:  a
383       given variable name may not be longer than 251 characters.  Line
384       numbers displayed by diagnostics are internally stored as short
385       integers, so they are limited to a maximum of 65535 (higher numbers
386       usually being affected by wraparound).
387
388       You may submit your bug reports (be sure to include full configuration
389       information as output by the myconfig program in the perl source tree,
390       or by "perl -V") to <https://github.com/Perl/perl5/issues>.
391
392       Perl actually stands for Pathologically Eclectic Rubbish Lister, but
393       don't tell anyone I said that.
394

NOTES

396       The Perl motto is "There's more than one way to do it."  Divining how
397       many more is left as an exercise to the reader.
398
399       The three principal virtues of a programmer are Laziness, Impatience,
400       and Hubris.  See the Camel Book for why.
401
402
403
404perl v5.32.1                      2021-03-31                           PERL(1)
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