1PERL(1) Perl Programmers Reference Guide PERL(1)
2
6 perl - The Perl 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
18 The perldoc program gives you access to all the documentation that
19 comes with Perl. You can get more documentation, tutorials and
20 community support online at <http://www.perl.org/>.
21 If you're new to Perl, you should start by running "perldoc perlintro",
23 which is a general intro for beginners and provides some background to
24 help you navigate the rest of Perl's extensive documentation. Run
25 "perldoc perldoc" to learn more things you can do with perldoc.
26 For ease of access, the Perl manual has been split up into several
28 sections.
29 Overview
31 perl Perl overview (this section)
32 perlintro Perl introduction for beginners
33 perltoc Perl documentation table of contents
34 Tutorials
36 perlreftut Perl references short introduction
37 perldsc Perl data structures intro
38 perllol Perl data structures: arrays of arrays
39 perlrequick Perl regular expressions quick start
41 perlretut Perl regular expressions tutorial
42 perlboot Perl OO tutorial for beginners
44 perltoot Perl OO tutorial, part 1
45 perltooc Perl OO tutorial, part 2
46 perlbot Perl OO tricks and examples
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 perlrun Perl execution and options
78 perldiag Perl diagnostic messages
79 perllexwarn Perl warnings and their control
80 perldebug Perl debugging
81 perlvar Perl predefined variables
82 perlre Perl regular expressions, the rest of the story
83 perlrebackslash Perl regular expression backslash sequences
84 perlrecharclass Perl regular expression character classes
85 perlreref Perl regular expressions quick reference
86 perlref Perl references, the rest of the story
87 perlform Perl formats
88 perlobj Perl objects
89 perltie Perl objects hidden behind simple variables
90 perldbmfilter Perl DBM filters
91 perlipc Perl interprocess communication
93 perlfork Perl fork() information
94 perlnumber Perl number semantics
95 perlthrtut Perl threads tutorial
97 perlport Perl portability guide
99 perllocale Perl locale support
100 perluniintro Perl Unicode introduction
101 perlunicode Perl Unicode support
102 perlunifaq Perl Unicode FAQ
103 perluniprops Index of Unicode Version 5.2.0 properties in Perl
104 perlunitut Perl Unicode tutorial
105 perlebcdic Considerations for running Perl on EBCDIC platforms
106 perlsec Perl security
108 perlmod Perl modules: how they work
110 perlmodlib Perl modules: how to write and use
111 perlmodstyle Perl modules: how to write modules with style
112 perlmodinstall Perl modules: how to install from CPAN
113 perlnewmod Perl modules: preparing a new module for distribution
114 perlpragma Perl modules: writing a user pragma
115 perlutil utilities packaged with the Perl distribution
117 perlcompile Perl compiler suite intro
119 perlfilter Perl source filters
121 perlglossary Perl Glossary
123 Internals and C Language Interface
125 perlembed Perl ways to embed perl in your C or C++ application
126 perldebguts Perl debugging guts and tips
127 perlxstut Perl XS tutorial
128 perlxs Perl XS application programming interface
129 perlclib Internal replacements for standard C library functions
130 perlguts Perl internal functions for those doing extensions
131 perlcall Perl calling conventions from C
132 perlmroapi Perl method resolution plugin interface
133 perlreapi Perl regular expression plugin interface
134 perlreguts Perl regular expression engine internals
135 perlapi Perl API listing (autogenerated)
137 perlintern Perl internal functions (autogenerated)
138 perliol C API for Perl's implementation of IO in Layers
139 perlapio Perl internal IO abstraction interface
140 perlhack Perl hackers guide
142 perlpolicy Perl development policies
143 perlrepository Perl source repository
144 Miscellaneous
146 perlbook Perl book information
147 perlcommunity Perl community information
148 perltodo Perl things to do
149 perldoc Look up Perl documentation in Pod format
151 perlhist Perl history records
153 perldelta Perl changes since previous version
154 perl5123delta Perl changes in version 5.12.3
155 perl5122delta Perl changes in version 5.12.2
156 perl5121delta Perl changes in version 5.12.1
157 perl5120delta Perl changes in version 5.12.0
158 perl5115delta Perl changes in version 5.11.5
159 perl5114delta Perl changes in version 5.11.4
160 perl5113delta Perl changes in version 5.11.3
161 perl5112delta Perl changes in version 5.11.2
162 perl5111delta Perl changes in version 5.11.1
163 perl5110delta Perl changes in version 5.11.0
164 perl5101delta Perl changes in version 5.10.1
165 perl5100delta Perl changes in version 5.10.0
166 perl595delta Perl changes in version 5.9.5
167 perl594delta Perl changes in version 5.9.4
168 perl593delta Perl changes in version 5.9.3
169 perl592delta Perl changes in version 5.9.2
170 perl591delta Perl changes in version 5.9.1
171 perl590delta Perl changes in version 5.9.0
172 perl589delta Perl changes in version 5.8.9
173 perl588delta Perl changes in version 5.8.8
174 perl587delta Perl changes in version 5.8.7
175 perl586delta Perl changes in version 5.8.6
176 perl585delta Perl changes in version 5.8.5
177 perl584delta Perl changes in version 5.8.4
178 perl583delta Perl changes in version 5.8.3
179 perl582delta Perl changes in version 5.8.2
180 perl581delta Perl changes in version 5.8.1
181 perl58delta Perl changes in version 5.8.0
182 perl573delta Perl changes in version 5.7.3
183 perl572delta Perl changes in version 5.7.2
184 perl571delta Perl changes in version 5.7.1
185 perl570delta Perl changes in version 5.7.0
186 perl561delta Perl changes in version 5.6.1
187 perl56delta Perl changes in version 5.6
188 perl5005delta Perl changes in version 5.005
189 perl5004delta Perl changes in version 5.004
190 perlartistic Perl Artistic License
192 perlgpl GNU General Public License
193 Language-Specific
195 perlcn Perl for Simplified Chinese (in EUC-CN)
196 perljp Perl for Japanese (in EUC-JP)
197 perlko Perl for Korean (in EUC-KR)
198 perltw Perl for Traditional Chinese (in Big5)
199 Platform-Specific
201 perlaix Perl notes for AIX
202 perlamiga Perl notes for AmigaOS
203 perlapollo Perl notes for Apollo DomainOS
204 perlbeos Perl notes for BeOS
205 perlbs2000 Perl notes for POSIX-BC BS2000
206 perlce Perl notes for WinCE
207 perlcygwin Perl notes for Cygwin
208 perldgux Perl notes for DG/UX
209 perldos Perl notes for DOS
210 perlepoc Perl notes for EPOC
211 perlfreebsd Perl notes for FreeBSD
212 perlhaiku Perl notes for Haiku
213 perlhpux Perl notes for HP-UX
214 perlhurd Perl notes for Hurd
215 perlirix Perl notes for Irix
216 perllinux Perl notes for Linux
217 perlmacos Perl notes for Mac OS (Classic)
218 perlmacosx Perl notes for Mac OS X
219 perlmpeix Perl notes for MPE/iX
220 perlnetware Perl notes for NetWare
221 perlopenbsd Perl notes for OpenBSD
222 perlos2 Perl notes for OS/2
223 perlos390 Perl notes for OS/390
224 perlos400 Perl notes for OS/400
225 perlplan9 Perl notes for Plan 9
226 perlqnx Perl notes for QNX
227 perlriscos Perl notes for RISC OS
228 perlsolaris Perl notes for Solaris
229 perlsymbian Perl notes for Symbian
230 perltru64 Perl notes for Tru64
231 perluts Perl notes for UTS
232 perlvmesa Perl notes for VM/ESA
233 perlvms Perl notes for VMS
234 perlvos Perl notes for Stratus VOS
235 perlwin32 Perl notes for Windows
236 On a Unix-like system, these documentation files will usually also be
238 available as manpages for use with the man program.
239 In general, if something strange has gone wrong with your program and
241 you're not sure where you should look for help, try the -w switch
242 first. It will often point out exactly where the trouble is.
243
245 Perl officially stands for Practical Extraction and Report Language,
246 except when it doesn't.
247 Perl is a language optimized for scanning arbitrary text files,
249 extracting information from those text files, and printing reports
250 based on that information. It's also a good language for many system
251 management tasks. The language is intended to be practical (easy to
252 use, efficient, complete) rather than beautiful (tiny, elegant,
253 minimal).
254 Perl combines (in the author's opinion, anyway) some of the best
256 features of C, sed, awk, and sh, so people familiar with those
257 languages should have little difficulty with it. (Language historians
258 will also note some vestiges of csh, Pascal, and even BASIC-PLUS.)
259 Expression syntax corresponds closely to C expression syntax. Unlike
260 most Unix utilities, Perl does not arbitrarily limit the size of your
261 data--if you've got the memory, Perl can slurp in your whole file as a
262 single string. Recursion is of unlimited depth. And the tables used
263 by hashes (sometimes called "associative arrays") grow as necessary to
264 prevent degraded performance. Perl can use sophisticated pattern
265 matching techniques to scan large amounts of data quickly. Although
266 optimized for scanning text, Perl can also deal with binary data, and
267 can make dbm files look like hashes. Setuid Perl scripts are safer
268 than C programs through a dataflow tracing mechanism that prevents many
269 stupid security holes.
270 If you have a problem that would ordinarily use sed or awk or sh, but
272 it exceeds their capabilities or must run a little faster, and you
273 don't want to write the silly thing in C, then Perl may be for you.
274 There are also translators to turn your sed and awk scripts into Perl
275 scripts.
276 But wait, there's more...
278 Begun in 1993 (see perlhist), Perl version 5 is nearly a complete
280 rewrite that provides the following additional benefits:
281 · modularity and reusability using innumerable modules
283 Described in perlmod, perlmodlib, and perlmodinstall.
285 · embeddable and extensible
287 Described in perlembed, perlxstut, perlxs, perlcall, perlguts, and
289 xsubpp.
290 · roll-your-own magic variables (including multiple simultaneous DBM
292 implementations)
293 Described in perltie and AnyDBM_File.
295 · subroutines can now be overridden, autoloaded, and prototyped
297 Described in perlsub.
299 · arbitrarily nested data structures and anonymous functions
301 Described in perlreftut, perlref, perldsc, and perllol.
303 · object-oriented programming
305 Described in perlobj, perlboot, perltoot, perltooc, and perlbot.
307 · support for light-weight processes (threads)
309 Described in perlthrtut and threads.
311 · support for Unicode, internationalization, and localization
313 Described in perluniintro, perllocale and Locale::Maketext.
315 · lexical scoping
317 Described in perlsub.
319 · regular expression enhancements
321 Described in perlre, with additional examples in perlop.
323 · enhanced debugger and interactive Perl environment, with integrated
325 editor support
326 Described in perldebtut, perldebug and perldebguts.
328 · POSIX 1003.1 compliant library
330 Described in POSIX.
332 Okay, that's definitely enough hype.
334
336 Perl is available for most operating systems, including virtually all
337 Unix-like platforms. See "Supported Platforms" in perlport for a
338 listing.
339
341 See perlrun.
342
344 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
345 If your Perl success stories and testimonials may be of help to others
347 who wish to advocate the use of Perl in their applications, or if you
348 wish to simply express your gratitude to Larry and the Perl developers,
349 please write to perl-thanks@perl.org .
350
352 "@INC" locations of perl libraries
353
355 a2p awk to perl translator
356 s2p sed to perl translator
357 http://www.perl.org/ the Perl homepage
359 http://www.perl.com/ Perl articles (O'Reilly)
360 http://www.cpan.org/ the Comprehensive Perl Archive
361 http://www.pm.org/ the Perl Mongers
362
364 The "use warnings" pragma (and the -w switch) produces some lovely
365 diagnostics.
366 See perldiag for explanations of all Perl's diagnostics. The "use
368 diagnostics" pragma automatically turns Perl's normally terse warnings
369 and errors into these longer forms.
370 Compilation errors will tell you the line number of the error, with an
372 indication of the next token or token type that was to be examined.
373 (In a script passed to Perl via -e switches, each -e is counted as one
374 line.)
375 Setuid scripts have additional constraints that can produce error
377 messages such as "Insecure dependency". See perlsec.
378 Did we mention that you should definitely consider using the -w switch?
380
382 The -w switch is not mandatory.
383 Perl is at the mercy of your machine's definitions of various
385 operations such as type casting, atof(), and floating-point output with
386 sprintf().
387 If your stdio requires a seek or eof between reads and writes on a
389 particular stream, so does Perl. (This doesn't apply to sysread() and
390 syswrite().)
391 While none of the built-in data types have any arbitrary size limits
393 (apart from memory size), there are still a few arbitrary limits: a
394 given variable name may not be longer than 251 characters. Line
395 numbers displayed by diagnostics are internally stored as short
396 integers, so they are limited to a maximum of 65535 (higher numbers
397 usually being affected by wraparound).
398 You may mail your bug reports (be sure to include full configuration
400 information as output by the myconfig program in the perl source tree,
401 or by "perl -V") to perlbug@perl.org . If you've succeeded in
402 compiling perl, the perlbug script in the utils/ subdirectory can be
403 used to help mail in a bug report.
404 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
406 don't tell anyone I said that.
407
409 The Perl motto is "There's more than one way to do it." Divining how
410 many more is left as an exercise to the reader.
411 The three principal virtues of a programmer are Laziness, Impatience,
413 and Hubris. See the Camel Book for why.
414perl v5.12.4 2011-06-10 PERL(1)