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 perl5281delta Perl changes in version 5.28.1
161 perl5280delta Perl changes in version 5.28.0
162 perl5263delta Perl changes in version 5.26.3
163 perl5262delta Perl changes in version 5.26.2
164 perl5261delta Perl changes in version 5.26.1
165 perl5260delta Perl changes in version 5.26.0
166 perl5244delta Perl changes in version 5.24.4
167 perl5243delta Perl changes in version 5.24.3
168 perl5242delta Perl changes in version 5.24.2
169 perl5241delta Perl changes in version 5.24.1
170 perl5240delta Perl changes in version 5.24.0
171 perl5224delta Perl changes in version 5.22.4
172 perl5223delta Perl changes in version 5.22.3
173 perl5222delta Perl changes in version 5.22.2
174 perl5221delta Perl changes in version 5.22.1
175 perl5220delta Perl changes in version 5.22.0
176 perl5203delta Perl changes in version 5.20.3
177 perl5202delta Perl changes in version 5.20.2
178 perl5201delta Perl changes in version 5.20.1
179 perl5200delta Perl changes in version 5.20.0
180 perl5184delta Perl changes in version 5.18.4
181 perl5182delta Perl changes in version 5.18.2
182 perl5181delta Perl changes in version 5.18.1
183 perl5180delta Perl changes in version 5.18.0
184 perl5163delta Perl changes in version 5.16.3
185 perl5162delta Perl changes in version 5.16.2
186 perl5161delta Perl changes in version 5.16.1
187 perl5160delta Perl changes in version 5.16.0
188 perl5144delta Perl changes in version 5.14.4
189 perl5143delta Perl changes in version 5.14.3
190 perl5142delta Perl changes in version 5.14.2
191 perl5141delta Perl changes in version 5.14.1
192 perl5140delta Perl changes in version 5.14.0
193 perl5125delta Perl changes in version 5.12.5
194 perl5124delta Perl changes in version 5.12.4
195 perl5123delta Perl changes in version 5.12.3
196 perl5122delta Perl changes in version 5.12.2
197 perl5121delta Perl changes in version 5.12.1
198 perl5120delta Perl changes in version 5.12.0
199 perl5101delta Perl changes in version 5.10.1
200 perl5100delta Perl changes in version 5.10.0
201 perl589delta Perl changes in version 5.8.9
202 perl588delta Perl changes in version 5.8.8
203 perl587delta Perl changes in version 5.8.7
204 perl586delta Perl changes in version 5.8.6
205 perl585delta Perl changes in version 5.8.5
206 perl584delta Perl changes in version 5.8.4
207 perl583delta Perl changes in version 5.8.3
208 perl582delta Perl changes in version 5.8.2
209 perl581delta Perl changes in version 5.8.1
210 perl58delta Perl changes in version 5.8.0
211 perl561delta Perl changes in version 5.6.1
212 perl56delta Perl changes in version 5.6
213 perl5005delta Perl changes in version 5.005
214 perl5004delta Perl changes in version 5.004
215 perlexperiment A listing of experimental features in Perl
217 perlartistic Perl Artistic License
219 perlgpl GNU General Public License
220 Language-Specific
222 perlcn Perl for Simplified Chinese (in EUC-CN)
223 perljp Perl for Japanese (in EUC-JP)
224 perlko Perl for Korean (in EUC-KR)
225 perltw Perl for Traditional Chinese (in Big5)
226 Platform-Specific
228 perlaix Perl notes for AIX
229 perlamiga Perl notes for AmigaOS
230 perlandroid Perl notes for Android
231 perlbs2000 Perl notes for POSIX-BC BS2000
232 perlce Perl notes for WinCE
233 perlcygwin Perl notes for Cygwin
234 perldos Perl notes for DOS
235 perlfreebsd Perl notes for FreeBSD
236 perlhaiku Perl notes for Haiku
237 perlhpux Perl notes for HP-UX
238 perlhurd Perl notes for Hurd
239 perlirix Perl notes for Irix
240 perllinux Perl notes for Linux
241 perlmacos Perl notes for Mac OS (Classic)
242 perlmacosx Perl notes for Mac OS X
243 perlnetware Perl notes for NetWare
244 perlopenbsd Perl notes for OpenBSD
245 perlos2 Perl notes for OS/2
246 perlos390 Perl notes for OS/390
247 perlos400 Perl notes for OS/400
248 perlplan9 Perl notes for Plan 9
249 perlqnx Perl notes for QNX
250 perlriscos Perl notes for RISC OS
251 perlsolaris Perl notes for Solaris
252 perlsymbian Perl notes for Symbian
253 perlsynology Perl notes for Synology
254 perltru64 Perl notes for Tru64
255 perlvms Perl notes for VMS
256 perlvos Perl notes for Stratus VOS
257 perlwin32 Perl notes for Windows
258 Stubs for Deleted Documents
260 perlboot
261 perlbot
262 perlrepository
263 perltodo
264 perltooc
265 perltoot
266 On a Unix-like system, these documentation files will usually also be
268 available as manpages for use with the man program.
269 Some documentation is not available as man pages, so if a cross-
271 reference is not found by man, try it with perldoc. Perldoc can also
272 take you directly to documentation for functions (with the -f switch).
273 See "perldoc --help" (or "perldoc perldoc" or "man perldoc") for other
274 helpful options perldoc has to offer.
275 In general, if something strange has gone wrong with your program and
277 you're not sure where you should look for help, try making your code
278 comply with use strict and use warnings. These will often point out
279 exactly where the trouble is.
280
282 Perl officially stands for Practical Extraction and Report Language,
283 except when it doesn't.
284 Perl was originally a language optimized for scanning arbitrary text
286 files, extracting information from those text files, and printing
287 reports based on that information. It quickly became a good language
288 for many system management tasks. Over the years, Perl has grown into a
289 general-purpose programming language. It's widely used for everything
290 from quick "one-liners" to full-scale application development.
291 The language is intended to be practical (easy to use, efficient,
293 complete) rather than beautiful (tiny, elegant, minimal). It combines
294 (in the author's opinion, anyway) some of the best features of sed,
295 awk, and sh, making it familiar and easy to use for Unix users to whip
296 up quick solutions to annoying problems. Its general-purpose
297 programming facilities support procedural, functional, and object-
298 oriented programming paradigms, making Perl a comfortable language for
299 the long haul on major projects, whatever your bent.
300 Perl's roots in text processing haven't been forgotten over the years.
302 It still boasts some of the most powerful regular expressions to be
303 found anywhere, and its support for Unicode text is world-class. It
304 handles all kinds of structured text, too, through an extensive
305 collection of extensions. Those libraries, collected in the CPAN,
306 provide ready-made solutions to an astounding array of problems. When
307 they haven't set the standard themselves, they steal from the best --
308 just like Perl itself.
309
311 Perl is available for most operating systems, including virtually all
312 Unix-like platforms. See "Supported Platforms" in perlport for a
313 listing.
314
316 See perlrun.
317
319 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
320 If your Perl success stories and testimonials may be of help to others
322 who wish to advocate the use of Perl in their applications, or if you
323 wish to simply express your gratitude to Larry and the Perl developers,
324 please write to perl-thanks@perl.org .
325
327 "@INC" locations of perl libraries
328 "@INC" above is a reference to the built-in variable of the same name;
330 see perlvar for more information.
331
333 http://www.perl.org/ the Perl homepage
334 http://www.perl.com/ Perl articles (O'Reilly)
335 http://www.cpan.org/ the Comprehensive Perl Archive
336 http://www.pm.org/ the Perl Mongers
337
339 Using the "use strict" pragma ensures that all variables are properly
340 declared and prevents other misuses of legacy Perl features.
341 The "use warnings" pragma produces some lovely diagnostics. One can
343 also use the -w flag, but its use is normally discouraged, because it
344 gets applied to all executed Perl code, including that not under your
345 control.
346 See perldiag for explanations of all Perl's diagnostics. The "use
348 diagnostics" pragma automatically turns Perl's normally terse warnings
349 and errors into these longer forms.
350 Compilation errors will tell you the line number of the error, with an
352 indication of the next token or token type that was to be examined.
353 (In a script passed to Perl via -e switches, each -e is counted as one
354 line.)
355 Setuid scripts have additional constraints that can produce error
357 messages such as "Insecure dependency". See perlsec.
358 Did we mention that you should definitely consider using the use
360 warnings pragma?
361
363 The behavior implied by the use warnings pragma is not mandatory.
364 Perl is at the mercy of your machine's definitions of various
366 operations such as type casting, atof(), and floating-point output with
367 sprintf().
368 If your stdio requires a seek or eof between reads and writes on a
370 particular stream, so does Perl. (This doesn't apply to sysread() and
371 syswrite().)
372 While none of the built-in data types have any arbitrary size limits
374 (apart from memory size), there are still a few arbitrary limits: a
375 given variable name may not be longer than 251 characters. Line
376 numbers displayed by diagnostics are internally stored as short
377 integers, so they are limited to a maximum of 65535 (higher numbers
378 usually being affected by wraparound).
379 You may mail your bug reports (be sure to include full configuration
381 information as output by the myconfig program in the perl source tree,
382 or by "perl -V") to perlbug@perl.org . If you've succeeded in
383 compiling perl, the perlbug script in the utils/ subdirectory can be
384 used to help mail in a bug report.
385 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
387 don't tell anyone I said that.
388
390 The Perl motto is "There's more than one way to do it." Divining how
391 many more is left as an exercise to the reader.
392 The three principal virtues of a programmer are Laziness, Impatience,
394 and Hubris. See the Camel Book for why.
395perl v5.28.2 2018-11-29 PERL(1)