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 <http://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 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 perlipc Perl interprocess communication
94 perlfork Perl fork() information
95 perlnumber Perl number semantics
96 perlthrtut Perl threads tutorial
98 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 perlsec Perl security
110 perlmod Perl modules: how they work
112 perlmodlib Perl modules: how to write and use
113 perlmodstyle Perl modules: how to write modules with style
114 perlmodinstall Perl modules: how to install from CPAN
115 perlnewmod Perl modules: preparing a new module for distribution
116 perlpragma Perl modules: writing a user pragma
117 perlutil utilities packaged with the Perl distribution
119 perlfilter Perl source filters
121 perldtrace Perl's support for DTrace
123 perlglossary Perl Glossary
125 Internals and C Language Interface
127 perlembed Perl ways to embed perl in your C or C++ application
128 perldebguts Perl debugging guts and tips
129 perlxstut Perl XS tutorial
130 perlxs Perl XS application programming interface
131 perlxstypemap Perl XS C/Perl type conversion tools
132 perlclib Internal replacements for standard C library functions
133 perlguts Perl internal functions for those doing extensions
134 perlcall Perl calling conventions from C
135 perlmroapi Perl method resolution plugin interface
136 perlreapi Perl regular expression plugin interface
137 perlreguts Perl regular expression engine internals
138 perlapi Perl API listing (autogenerated)
140 perlintern Perl internal functions (autogenerated)
141 perliol C API for Perl's implementation of IO in Layers
142 perlapio Perl internal IO abstraction interface
143 perlhack Perl hackers guide
145 perlsource Guide to the Perl source tree
146 perlinterp Overview of the Perl interpreter source and how it works
147 perlhacktut Walk through the creation of a simple C code patch
148 perlhacktips Tips for Perl core C code hacking
149 perlpolicy Perl development policies
150 perlgit Using git with the Perl repository
151 Miscellaneous
153 perlbook Perl book information
154 perlcommunity Perl community information
155 perldoc Look up Perl documentation in Pod format
157 perlhist Perl history records
159 perldelta Perl changes since previous version
160 perl5301delta Perl changes in version 5.30.1
161 perl5300delta Perl changes in version 5.30.0
162 perl5282delta Perl changes in version 5.28.2
163 perl5281delta Perl changes in version 5.28.1
164 perl5280delta Perl changes in version 5.28.0
165 perl5263delta Perl changes in version 5.26.3
166 perl5262delta Perl changes in version 5.26.2
167 perl5261delta Perl changes in version 5.26.1
168 perl5260delta Perl changes in version 5.26.0
169 perl5244delta Perl changes in version 5.24.4
170 perl5243delta Perl changes in version 5.24.3
171 perl5242delta Perl changes in version 5.24.2
172 perl5241delta Perl changes in version 5.24.1
173 perl5240delta Perl changes in version 5.24.0
174 perl5224delta Perl changes in version 5.22.4
175 perl5223delta Perl changes in version 5.22.3
176 perl5222delta Perl changes in version 5.22.2
177 perl5221delta Perl changes in version 5.22.1
178 perl5220delta Perl changes in version 5.22.0
179 perl5203delta Perl changes in version 5.20.3
180 perl5202delta Perl changes in version 5.20.2
181 perl5201delta Perl changes in version 5.20.1
182 perl5200delta Perl changes in version 5.20.0
183 perl5184delta Perl changes in version 5.18.4
184 perl5182delta Perl changes in version 5.18.2
185 perl5181delta Perl changes in version 5.18.1
186 perl5180delta Perl changes in version 5.18.0
187 perl5163delta Perl changes in version 5.16.3
188 perl5162delta Perl changes in version 5.16.2
189 perl5161delta Perl changes in version 5.16.1
190 perl5160delta Perl changes in version 5.16.0
191 perl5144delta Perl changes in version 5.14.4
192 perl5143delta Perl changes in version 5.14.3
193 perl5142delta Perl changes in version 5.14.2
194 perl5141delta Perl changes in version 5.14.1
195 perl5140delta Perl changes in version 5.14.0
196 perl5125delta Perl changes in version 5.12.5
197 perl5124delta Perl changes in version 5.12.4
198 perl5123delta Perl changes in version 5.12.3
199 perl5122delta Perl changes in version 5.12.2
200 perl5121delta Perl changes in version 5.12.1
201 perl5120delta Perl changes in version 5.12.0
202 perl5101delta Perl changes in version 5.10.1
203 perl5100delta Perl changes in version 5.10.0
204 perl589delta Perl changes in version 5.8.9
205 perl588delta Perl changes in version 5.8.8
206 perl587delta Perl changes in version 5.8.7
207 perl586delta Perl changes in version 5.8.6
208 perl585delta Perl changes in version 5.8.5
209 perl584delta Perl changes in version 5.8.4
210 perl583delta Perl changes in version 5.8.3
211 perl582delta Perl changes in version 5.8.2
212 perl581delta Perl changes in version 5.8.1
213 perl58delta Perl changes in version 5.8.0
214 perl561delta Perl changes in version 5.6.1
215 perl56delta Perl changes in version 5.6
216 perl5005delta Perl changes in version 5.005
217 perl5004delta Perl changes in version 5.004
218 perlexperiment A listing of experimental features in Perl
220 perlartistic Perl Artistic License
222 perlgpl GNU General Public License
223 Language-Specific
225 perlcn Perl for Simplified Chinese (in EUC-CN)
226 perljp Perl for Japanese (in EUC-JP)
227 perlko Perl for Korean (in EUC-KR)
228 perltw Perl for Traditional Chinese (in Big5)
229 Platform-Specific
231 perlaix Perl notes for AIX
232 perlamiga Perl notes for AmigaOS
233 perlandroid Perl notes for Android
234 perlbs2000 Perl notes for POSIX-BC BS2000
235 perlce Perl notes for WinCE
236 perlcygwin Perl notes for Cygwin
237 perldos Perl notes for DOS
238 perlfreebsd Perl notes for FreeBSD
239 perlhaiku Perl notes for Haiku
240 perlhpux Perl notes for HP-UX
241 perlhurd Perl notes for Hurd
242 perlirix Perl notes for Irix
243 perllinux Perl notes for Linux
244 perlmacos Perl notes for Mac OS (Classic)
245 perlmacosx Perl notes for Mac OS X
246 perlnetware Perl notes for NetWare
247 perlopenbsd Perl notes for OpenBSD
248 perlos2 Perl notes for OS/2
249 perlos390 Perl notes for OS/390
250 perlos400 Perl notes for OS/400
251 perlplan9 Perl notes for Plan 9
252 perlqnx Perl notes for QNX
253 perlriscos Perl notes for RISC OS
254 perlsolaris Perl notes for Solaris
255 perlsymbian Perl notes for Symbian
256 perlsynology Perl notes for Synology
257 perltru64 Perl notes for Tru64
258 perlvms Perl notes for VMS
259 perlvos Perl notes for Stratus VOS
260 perlwin32 Perl notes for Windows
261 Stubs for Deleted Documents
263 perlboot
264 perlbot
265 perlrepository
266 perltodo
267 perltooc
268 perltoot
269 On a Unix-like system, these documentation files will usually also be
271 available as manpages for use with the man program.
272 Some documentation is not available as man pages, so if a cross-
274 reference is not found by man, try it with perldoc. Perldoc can also
275 take you directly to documentation for functions (with the -f switch).
276 See "perldoc --help" (or "perldoc perldoc" or "man perldoc") for other
277 helpful options perldoc has to offer.
278 In general, if something strange has gone wrong with your program and
280 you're not sure where you should look for help, try making your code
281 comply with use strict and use warnings. These will often point out
282 exactly where the trouble is.
283
285 Perl officially stands for Practical Extraction and Report Language,
286 except when it doesn't.
287 Perl was originally a language optimized for scanning arbitrary text
289 files, extracting information from those text files, and printing
290 reports based on that information. It quickly became a good language
291 for many system management tasks. Over the years, Perl has grown into a
292 general-purpose programming language. It's widely used for everything
293 from quick "one-liners" to full-scale application development.
294 The language is intended to be practical (easy to use, efficient,
296 complete) rather than beautiful (tiny, elegant, minimal). It combines
297 (in the author's opinion, anyway) some of the best features of sed,
298 awk, and sh, making it familiar and easy to use for Unix users to whip
299 up quick solutions to annoying problems. Its general-purpose
300 programming facilities support procedural, functional, and object-
301 oriented programming paradigms, making Perl a comfortable language for
302 the long haul on major projects, whatever your bent.
303 Perl's roots in text processing haven't been forgotten over the years.
305 It still boasts some of the most powerful regular expressions to be
306 found anywhere, and its support for Unicode text is world-class. It
307 handles all kinds of structured text, too, through an extensive
308 collection of extensions. Those libraries, collected in the CPAN,
309 provide ready-made solutions to an astounding array of problems. When
310 they haven't set the standard themselves, they steal from the best --
311 just like Perl itself.
312
314 Perl is available for most operating systems, including virtually all
315 Unix-like platforms. See "Supported Platforms" in perlport for a
316 listing.
317
319 See perlrun.
320
322 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
323 If your Perl success stories and testimonials may be of help to others
325 who wish to advocate the use of Perl in their applications, or if you
326 wish to simply express your gratitude to Larry and the Perl developers,
327 please write to perl-thanks@perl.org .
328
330 "@INC" locations of perl libraries
331 "@INC" above is a reference to the built-in variable of the same name;
333 see perlvar for more information.
334
336 http://www.perl.org/ the Perl homepage
337 http://www.perl.com/ Perl articles (O'Reilly)
338 http://www.cpan.org/ the Comprehensive Perl Archive
339 http://www.pm.org/ the Perl Mongers
340
342 Using the "use strict" pragma ensures that all variables are properly
343 declared and prevents other misuses of legacy Perl features.
344 The "use warnings" pragma produces some lovely diagnostics. One can
346 also use the -w flag, but its use is normally discouraged, because it
347 gets applied to all executed Perl code, including that not under your
348 control.
349 See perldiag for explanations of all Perl's diagnostics. The "use
351 diagnostics" pragma automatically turns Perl's normally terse warnings
352 and errors into these longer forms.
353 Compilation errors will tell you the line number of the error, with an
355 indication of the next token or token type that was to be examined.
356 (In a script passed to Perl via -e switches, each -e is counted as one
357 line.)
358 Setuid scripts have additional constraints that can produce error
360 messages such as "Insecure dependency". See perlsec.
361 Did we mention that you should definitely consider using the use
363 warnings pragma?
364
366 The behavior implied by the use warnings pragma is not mandatory.
367 Perl is at the mercy of your machine's definitions of various
369 operations such as type casting, atof(), and floating-point output with
370 sprintf().
371 If your stdio requires a seek or eof between reads and writes on a
373 particular stream, so does Perl. (This doesn't apply to sysread() and
374 syswrite().)
375 While none of the built-in data types have any arbitrary size limits
377 (apart from memory size), there are still a few arbitrary limits: a
378 given variable name may not be longer than 251 characters. Line
379 numbers displayed by diagnostics are internally stored as short
380 integers, so they are limited to a maximum of 65535 (higher numbers
381 usually being affected by wraparound).
382 You may submit your bug reports (be sure to include full configuration
384 information as output by the myconfig program in the perl source tree,
385 or by "perl -V") to <https://github.com/Perl/perl5/issues>.
386 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
388 don't tell anyone I said that.
389
391 The Perl motto is "There's more than one way to do it." Divining how
392 many more is left as an exercise to the reader.
393 The three principal virtues of a programmer are Laziness, Impatience,
395 and Hubris. See the Camel Book for why.
396perl v5.30.2 2020-03-27 PERL(1)