1PERL(1) Perl Programmers Reference Guide PERL(1)
2
6 perl - The Perl 5 language interpreter
7
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 For more information on these options, you can run "perldoc perlrun".
18
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 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 For ease of access, the Perl manual has been split up into several
30 sections.
31 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 Tutorials
39 perlreftut Perl references short introduction
40 perldsc Perl data structures intro
41 perllol Perl data structures: arrays of arrays
42 perlrequick Perl regular expressions quick start
44 perlretut Perl regular expressions tutorial
45 perlootut Perl OO tutorial for beginners
47 perlperf Perl Performance and Optimization Techniques
49 perlstyle Perl style guide
51 perlcheat Perl cheat sheet
53 perltrap Perl traps for the unwary
54 perldebtut Perl debugging tutorial
55 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 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 perldocstyle Perl style guide for core docs
78 perlpodstyle Perl POD style guide
79 perldiag Perl diagnostic messages
80 perldeprecation Perl deprecations
81 perllexwarn Perl warnings and their control
82 perldebug Perl debugging
83 perlvar Perl predefined variables
84 perlre Perl regular expressions, the rest of the story
85 perlrebackslash Perl regular expression backslash sequences
86 perlrecharclass Perl regular expression character classes
87 perlreref Perl regular expressions quick reference
88 perlref Perl references, the rest of the story
89 perlform Perl formats
90 perlobj Perl objects
91 perltie Perl objects hidden behind simple variables
92 perldbmfilter Perl DBM filters
93 perlipc Perl interprocess communication
95 perlfork Perl fork() information
96 perlnumber Perl number semantics
97 perlthrtut Perl threads tutorial
99 perlport Perl portability guide
101 perllocale Perl locale support
102 perluniintro Perl Unicode introduction
103 perlunicode Perl Unicode support
104 perlunicook Perl Unicode cookbook
105 perlunifaq Perl Unicode FAQ
106 perluniprops Index of Unicode properties in Perl
107 perlunitut Perl Unicode tutorial
108 perlebcdic Considerations for running Perl on EBCDIC platforms
109 perlsec Perl security
111 perlsecpolicy Perl security report handling policy
112 perlmod Perl modules: how they work
114 perlmodlib Perl modules: how to write and use
115 perlmodstyle Perl modules: how to write modules with style
116 perlmodinstall Perl modules: how to install from CPAN
117 perlnewmod Perl modules: preparing a new module for distribution
118 perlpragma Perl modules: writing a user pragma
119 perlutil utilities packaged with the Perl distribution
121 perlfilter Perl source filters
123 perldtrace Perl's support for DTrace
125 perlglossary Perl Glossary
127 Internals and C Language Interface
129 perlembed Perl ways to embed perl in your C or C++ application
130 perldebguts Perl debugging guts and tips
131 perlxstut Perl XS tutorial
132 perlxs Perl XS application programming interface
133 perlxstypemap Perl XS C/Perl type conversion tools
134 perlclib Internal replacements for standard C library functions
135 perlguts Perl internal functions for those doing extensions
136 perlcall Perl calling conventions from C
137 perlmroapi Perl method resolution plugin interface
138 perlreapi Perl regular expression plugin interface
139 perlreguts Perl regular expression engine internals
140 perlapi Perl API listing (autogenerated)
142 perlintern Perl internal functions (autogenerated)
143 perliol C API for Perl's implementation of IO in Layers
144 perlapio Perl internal IO abstraction interface
145 perlhack Perl hackers guide
147 perlsource Guide to the Perl source tree
148 perlinterp Overview of the Perl interpreter source and how it works
149 perlhacktut Walk through the creation of a simple C code patch
150 perlhacktips Tips for Perl core C code hacking
151 perlpolicy Perl development policies
152 perlgov Perl Rules of Governance
153 perlgit Using git with the Perl repository
154 History
156 perlhist Perl history records
157 perldelta Perl changes since previous version
158 perl5341delta Perl changes in version 5.34.1
159 perl5340delta Perl changes in version 5.34.0
160 perl5321delta Perl changes in version 5.32.1
161 perl5320delta Perl changes in version 5.32.0
162 perl5303delta Perl changes in version 5.30.3
163 perl5302delta Perl changes in version 5.30.2
164 perl5301delta Perl changes in version 5.30.1
165 perl5300delta Perl changes in version 5.30.0
166 perl5283delta Perl changes in version 5.28.3
167 perl5282delta Perl changes in version 5.28.2
168 perl5281delta Perl changes in version 5.28.1
169 perl5280delta Perl changes in version 5.28.0
170 perl5263delta Perl changes in version 5.26.3
171 perl5262delta Perl changes in version 5.26.2
172 perl5261delta Perl changes in version 5.26.1
173 perl5260delta Perl changes in version 5.26.0
174 perl5244delta Perl changes in version 5.24.4
175 perl5243delta Perl changes in version 5.24.3
176 perl5242delta Perl changes in version 5.24.2
177 perl5241delta Perl changes in version 5.24.1
178 perl5240delta Perl changes in version 5.24.0
179 perl5224delta Perl changes in version 5.22.4
180 perl5223delta Perl changes in version 5.22.3
181 perl5222delta Perl changes in version 5.22.2
182 perl5221delta Perl changes in version 5.22.1
183 perl5220delta Perl changes in version 5.22.0
184 perl5203delta Perl changes in version 5.20.3
185 perl5202delta Perl changes in version 5.20.2
186 perl5201delta Perl changes in version 5.20.1
187 perl5200delta Perl changes in version 5.20.0
188 perl5184delta Perl changes in version 5.18.4
189 perl5182delta Perl changes in version 5.18.2
190 perl5181delta Perl changes in version 5.18.1
191 perl5180delta Perl changes in version 5.18.0
192 perl5163delta Perl changes in version 5.16.3
193 perl5162delta Perl changes in version 5.16.2
194 perl5161delta Perl changes in version 5.16.1
195 perl5160delta Perl changes in version 5.16.0
196 perl5144delta Perl changes in version 5.14.4
197 perl5143delta Perl changes in version 5.14.3
198 perl5142delta Perl changes in version 5.14.2
199 perl5141delta Perl changes in version 5.14.1
200 perl5140delta Perl changes in version 5.14.0
201 perl5125delta Perl changes in version 5.12.5
202 perl5124delta Perl changes in version 5.12.4
203 perl5123delta Perl changes in version 5.12.3
204 perl5122delta Perl changes in version 5.12.2
205 perl5121delta Perl changes in version 5.12.1
206 perl5120delta Perl changes in version 5.12.0
207 perl5101delta Perl changes in version 5.10.1
208 perl5100delta Perl changes in version 5.10.0
209 perl589delta Perl changes in version 5.8.9
210 perl588delta Perl changes in version 5.8.8
211 perl587delta Perl changes in version 5.8.7
212 perl586delta Perl changes in version 5.8.6
213 perl585delta Perl changes in version 5.8.5
214 perl584delta Perl changes in version 5.8.4
215 perl583delta Perl changes in version 5.8.3
216 perl582delta Perl changes in version 5.8.2
217 perl581delta Perl changes in version 5.8.1
218 perl58delta Perl changes in version 5.8.0
219 perl561delta Perl changes in version 5.6.1
220 perl56delta Perl changes in version 5.6
221 perl5005delta Perl changes in version 5.005
222 perl5004delta Perl changes in version 5.004
223 Miscellaneous
225 perlbook Perl book information
226 perlcommunity Perl community information
227 perldoc Look up Perl documentation in Pod format
229 perlexperiment A listing of experimental features in Perl
231 perlartistic Perl Artistic License
233 perlgpl GNU General Public License
234 Language-Specific
236 perlcn Perl for Simplified Chinese (in UTF-8)
237 perljp Perl for Japanese (in EUC-JP)
238 perlko Perl for Korean (in EUC-KR)
239 perltw Perl for Traditional Chinese (in Big5)
240 Platform-Specific
242 perlaix Perl notes for AIX
243 perlamiga Perl notes for AmigaOS
244 perlandroid Perl notes for Android
245 perlbs2000 Perl notes for POSIX-BC BS2000
246 perlcygwin Perl notes for Cygwin
247 perlfreebsd Perl notes for FreeBSD
248 perlhaiku Perl notes for Haiku
249 perlhpux Perl notes for HP-UX
250 perlhurd Perl notes for Hurd
251 perlirix Perl notes for Irix
252 perllinux Perl notes for Linux
253 perlmacosx Perl notes for Mac OS X
254 perlopenbsd Perl notes for OpenBSD
255 perlos2 Perl notes for OS/2
256 perlos390 Perl notes for OS/390
257 perlos400 Perl notes for OS/400
258 perlplan9 Perl notes for Plan 9
259 perlqnx Perl notes for QNX
260 perlriscos Perl notes for RISC OS
261 perlsolaris Perl notes for Solaris
262 perlsynology Perl notes for Synology
263 perltru64 Perl notes for Tru64
264 perlvms Perl notes for VMS
265 perlvos Perl notes for Stratus VOS
266 perlwin32 Perl notes for Windows
267 Stubs for Deleted Documents
269 perlboot
270 perlbot
271 perlrepository
272 perltodo
273 perltooc
274 perltoot
275 On a Unix-like system, these documentation files will usually also be
277 available as manpages for use with the man program.
278 Some documentation is not available as man pages, so if a cross-
280 reference is not found by man, try it with perldoc. Perldoc can also
281 take you directly to documentation for functions (with the -f switch).
282 See "perldoc --help" (or "perldoc perldoc" or "man perldoc") for other
283 helpful options perldoc has to offer.
284 In general, if something strange has gone wrong with your program and
286 you're not sure where you should look for help, try making your code
287 comply with use strict and use warnings. These will often point out
288 exactly where the trouble is.
289
291 Perl officially stands for Practical Extraction and Report Language,
292 except when it doesn't.
293 Perl was originally a language optimized for scanning arbitrary text
295 files, extracting information from those text files, and printing
296 reports based on that information. It quickly became a good language
297 for many system management tasks. Over the years, Perl has grown into a
298 general-purpose programming language. It's widely used for everything
299 from quick "one-liners" to full-scale application development.
300 The language is intended to be practical (easy to use, efficient,
302 complete) rather than beautiful (tiny, elegant, minimal). It combines
303 (in the author's opinion, anyway) some of the best features of sed,
304 awk, and sh, making it familiar and easy to use for Unix users to whip
305 up quick solutions to annoying problems. Its general-purpose
306 programming facilities support procedural, functional, and object-
307 oriented programming paradigms, making Perl a comfortable language for
308 the long haul on major projects, whatever your bent.
309 Perl's roots in text processing haven't been forgotten over the years.
311 It still boasts some of the most powerful regular expressions to be
312 found anywhere, and its support for Unicode text is world-class. It
313 handles all kinds of structured text, too, through an extensive
314 collection of extensions. Those libraries, collected in the CPAN,
315 provide ready-made solutions to an astounding array of problems. When
316 they haven't set the standard themselves, they steal from the best --
317 just like Perl itself.
318
320 Perl is available for most operating systems, including virtually all
321 Unix-like platforms. See "Supported Platforms" in perlport for a
322 listing.
323
325 See "ENVIRONMENT" in perlrun.
326
328 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
329 If your Perl success stories and testimonials may be of help to others
331 who wish to advocate the use of Perl in their applications, or if you
332 wish to simply express your gratitude to Larry and the Perl developers,
333 please write to perl-thanks@perl.org .
334
336 "@INC" locations of perl libraries
337 "@INC" above is a reference to the built-in variable of the same name;
339 see perlvar for more information.
340
342 https://www.perl.org/ the Perl homepage
343 https://www.perl.com/ Perl articles
344 https://www.cpan.org/ the Comprehensive Perl Archive
345 https://www.pm.org/ the Perl Mongers
346
348 Using the "use strict" pragma ensures that all variables are properly
349 declared and prevents other misuses of legacy Perl features. These are
350 enabled by default within the scope of "use v5.12" (or higher).
351 The "use warnings" pragma produces some lovely diagnostics. It is
353 enabled by default when you say "use v5.35" (or higher). One can also
354 use the -w flag, but its use is normally discouraged, because it gets
355 applied to all executed Perl code, including that not under your
356 control.
357 See perldiag for explanations of all Perl's diagnostics. The "use
359 diagnostics" pragma automatically turns Perl's normally terse warnings
360 and errors into these longer forms.
361 Compilation errors will tell you the line number of the error, with an
363 indication of the next token or token type that was to be examined.
364 (In a script passed to Perl via -e switches, each -e is counted as one
365 line.)
366 Setuid scripts have additional constraints that can produce error
368 messages such as "Insecure dependency". See perlsec.
369 Did we mention that you should definitely consider using the use
371 warnings pragma?
372
374 The behavior implied by the use warnings pragma is not mandatory.
375 Perl is at the mercy of your machine's definitions of various
377 operations such as type casting, atof(), and floating-point output with
378 sprintf().
379 If your stdio requires a seek or eof between reads and writes on a
381 particular stream, so does Perl. (This doesn't apply to sysread() and
382 syswrite().)
383 While none of the built-in data types have any arbitrary size limits
385 (apart from memory size), there are still a few arbitrary limits: a
386 given variable name may not be longer than 251 characters. Line
387 numbers displayed by diagnostics are internally stored as short
388 integers, so they are limited to a maximum of 65535 (higher numbers
389 usually being affected by wraparound).
390 You may submit your bug reports (be sure to include full configuration
392 information as output by the myconfig program in the perl source tree,
393 or by "perl -V") to <https://github.com/Perl/perl5/issues>.
394 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
396 don't tell anyone I said that.
397
399 The Perl motto is "There's more than one way to do it." Divining how
400 many more is left as an exercise to the reader.
401 The three principal virtues of a programmer are Laziness, Impatience,
403 and Hubris. See the Camel Book for why.
404perl v5.36.0 2022-08-30 PERL(1)