3 perl - The Perl language interpreter
7 B<perl> S<[ B<-sTtuUWX> ]>
8 S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
9 S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
10 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
11 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]>
12 S<[ B<-C [I<number/list>] >]>
15 S<[ B<-i>[I<extension>] ]>
16 S<[ [B<-e>|B<-E>] I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
20 The F<perldoc> program gives you access to all the documentation that comes
21 with Perl. You can get more documentation, tutorials and community support
22 online at L<http://www.perl.org/>.
24 If you're new to Perl, you should start by running C<perldoc perlintro>,
25 which is a general intro for beginners and provides some background to help
26 you navigate the rest of Perl's extensive documentation. Run C<perldoc
27 perldoc> to learn more things you can do with F<perldoc>.
29 For ease of access, the Perl manual has been split up into several sections.
33 perl Perl overview (this section)
34 perlintro Perl introduction for beginners
35 perltoc Perl documentation table of contents
39 perlreftut Perl references short introduction
40 perldsc Perl data structures intro
41 perllol Perl data structures: arrays of arrays
43 perlrequick Perl regular expressions quick start
44 perlretut Perl regular expressions tutorial
46 perlboot Perl OO tutorial for beginners
47 perltoot Perl OO tutorial, part 1
48 perltooc Perl OO tutorial, part 2
49 perlbot Perl OO tricks and examples
51 perlperf Perl Performance and Optimization Techniques
53 perlstyle Perl style guide
55 perlcheat Perl cheat sheet
56 perltrap Perl traps for the unwary
57 perldebtut Perl debugging tutorial
59 perlfaq Perl frequently asked questions
60 perlfaq1 General Questions About Perl
61 perlfaq2 Obtaining and Learning about Perl
62 perlfaq3 Programming Tools
63 perlfaq4 Data Manipulation
64 perlfaq5 Files and Formats
66 perlfaq7 Perl Language Issues
67 perlfaq8 System Interaction
70 =head2 Reference Manual
73 perldata Perl data structures
74 perlop Perl operators and precedence
75 perlsub Perl subroutines
76 perlfunc Perl built-in functions
77 perlopentut Perl open() tutorial
78 perlpacktut Perl pack() and unpack() tutorial
79 perlpod Perl plain old documentation
80 perlpodspec Perl plain old documentation format specification
81 perlrun Perl execution and options
82 perldiag Perl diagnostic messages
83 perllexwarn Perl warnings and their control
84 perldebug Perl debugging
85 perlvar Perl predefined variables
86 perlre Perl regular expressions, the rest of the story
87 perlrebackslash Perl regular expression backslash sequences
88 perlrecharclass Perl regular expression character classes
89 perlreref Perl regular expressions quick reference
90 perlref Perl references, the rest of the story
93 perltie Perl objects hidden behind simple variables
94 perldbmfilter Perl DBM filters
96 perlipc Perl interprocess communication
97 perlfork Perl fork() information
98 perlnumber Perl number semantics
100 perlthrtut Perl threads tutorial
102 perlport Perl portability guide
103 perllocale Perl locale support
104 perluniintro Perl Unicode introduction
105 perlunicode Perl Unicode support
106 perlunifaq Perl Unicode FAQ
107 perluniprops Index of Unicode Version 5.2.0 properties in Perl
108 perlunitut Perl Unicode tutorial
109 perlebcdic Considerations for running Perl on EBCDIC platforms
111 perlsec Perl security
113 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
120 perlutil utilities packaged with the Perl distribution
122 perlcompile Perl compiler suite intro
124 perlfilter Perl source filters
126 perlglossary Perl Glossary
128 =head2 Internals and C Language Interface
130 perlembed Perl ways to embed perl in your C or C++ application
131 perldebguts Perl debugging guts and tips
132 perlxstut Perl XS tutorial
133 perlxs Perl XS application programming interface
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
141 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
146 perlhack Perl hackers guide
147 perlpolicy Perl development policies
148 perlrepository Perl source repository
152 perlbook Perl book information
153 perlcommunity Perl community information
154 perltodo Perl things to do
156 perldoc Look up Perl documentation in Pod format
158 perlhist Perl history records
159 perl5130delta Perl changes in version 5.13.0
160 perl5120delta Perl changes in version 5.12.0
161 perldelta Perl changes since previous version
162 perl5115delta Perl changes in version 5.11.5
163 perl5114delta Perl changes in version 5.11.4
164 perl5113delta Perl changes in version 5.11.3
165 perl5112delta Perl changes in version 5.11.2
166 perl5111delta Perl changes in version 5.11.1
167 perl5110delta Perl changes in version 5.11.0
168 perl5101delta Perl changes in version 5.10.1
169 perl5100delta Perl changes in version 5.10.0
170 perl595delta Perl changes in version 5.9.5
171 perl594delta Perl changes in version 5.9.4
172 perl593delta Perl changes in version 5.9.3
173 perl592delta Perl changes in version 5.9.2
174 perl591delta Perl changes in version 5.9.1
175 perl590delta Perl changes in version 5.9.0
176 perl589delta Perl changes in version 5.8.9
177 perl588delta Perl changes in version 5.8.8
178 perl587delta Perl changes in version 5.8.7
179 perl586delta Perl changes in version 5.8.6
180 perl585delta Perl changes in version 5.8.5
181 perl584delta Perl changes in version 5.8.4
182 perl583delta Perl changes in version 5.8.3
183 perl582delta Perl changes in version 5.8.2
184 perl581delta Perl changes in version 5.8.1
185 perl58delta Perl changes in version 5.8.0
186 perl573delta Perl changes in version 5.7.3
187 perl572delta Perl changes in version 5.7.2
188 perl571delta Perl changes in version 5.7.1
189 perl570delta Perl changes in version 5.7.0
190 perl561delta Perl changes in version 5.6.1
191 perl56delta Perl changes in version 5.6
192 perl5005delta Perl changes in version 5.005
193 perl5004delta Perl changes in version 5.004
195 perlartistic Perl Artistic License
196 perlgpl GNU General Public License
198 =head2 Language-Specific
200 perlcn Perl for Simplified Chinese (in EUC-CN)
201 perljp Perl for Japanese (in EUC-JP)
202 perlko Perl for Korean (in EUC-KR)
203 perltw Perl for Traditional Chinese (in Big5)
205 =head2 Platform-Specific
207 perlaix Perl notes for AIX
208 perlamiga Perl notes for AmigaOS
209 perlapollo Perl notes for Apollo DomainOS
210 perlbeos Perl notes for BeOS
211 perlbs2000 Perl notes for POSIX-BC BS2000
212 perlce Perl notes for WinCE
213 perlcygwin Perl notes for Cygwin
214 perldgux Perl notes for DG/UX
215 perldos Perl notes for DOS
216 perlepoc Perl notes for EPOC
217 perlfreebsd Perl notes for FreeBSD
218 perlhaiku Perl notes for Haiku
219 perlhpux Perl notes for HP-UX
220 perlhurd Perl notes for Hurd
221 perlirix Perl notes for Irix
222 perllinux Perl notes for Linux
223 perlmacos Perl notes for Mac OS (Classic)
224 perlmacosx Perl notes for Mac OS X
225 perlmpeix Perl notes for MPE/iX
226 perlnetware Perl notes for NetWare
227 perlopenbsd Perl notes for OpenBSD
228 perlos2 Perl notes for OS/2
229 perlos390 Perl notes for OS/390
230 perlos400 Perl notes for OS/400
231 perlplan9 Perl notes for Plan 9
232 perlqnx Perl notes for QNX
233 perlriscos Perl notes for RISC OS
234 perlsolaris Perl notes for Solaris
235 perlsymbian Perl notes for Symbian
236 perltru64 Perl notes for Tru64
237 perluts Perl notes for UTS
238 perlvmesa Perl notes for VM/ESA
239 perlvms Perl notes for VMS
240 perlvos Perl notes for Stratus VOS
241 perlwin32 Perl notes for Windows
244 On a Unix-like system, these documentation files will usually also be
245 available as manpages for use with the F<man> program.
247 In general, if something strange has gone wrong with your program and you're
248 not sure where you should look for help, try the B<-w> switch first. It will
249 often point out exactly where the trouble is.
253 Perl officially stands for Practical Extraction and Report Language,
254 except when it doesn't.
256 Perl is a language optimized for scanning arbitrary
257 text files, extracting information from those text files, and printing
258 reports based on that information. It's also a good language for many
259 system management tasks. The language is intended to be practical
260 (easy to use, efficient, complete) rather than beautiful (tiny,
263 Perl combines (in the author's opinion, anyway) some of the best
264 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
265 those languages should have little difficulty with it. (Language
266 historians will also note some vestiges of B<csh>, Pascal, and even
267 BASIC-PLUS.) Expression syntax corresponds closely to C
268 expression syntax. Unlike most Unix utilities, Perl does not
269 arbitrarily limit the size of your data--if you've got the memory,
270 Perl can slurp in your whole file as a single string. Recursion is of
271 unlimited depth. And the tables used by hashes (sometimes called
272 "associative arrays") grow as necessary to prevent degraded
273 performance. Perl can use sophisticated pattern matching techniques to
274 scan large amounts of data quickly. Although optimized for
275 scanning text, Perl can also deal with binary data, and can make dbm
276 files look like hashes. Setuid Perl scripts are safer than C programs
277 through a dataflow tracing mechanism that prevents many stupid
280 If you have a problem that would ordinarily use B<sed> or B<awk> or
281 B<sh>, but it exceeds their capabilities or must run a little faster,
282 and you don't want to write the silly thing in C, then Perl may be for
283 you. There are also translators to turn your B<sed> and B<awk>
284 scripts into Perl scripts.
286 But wait, there's more...
288 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
289 rewrite that provides the following additional benefits:
295 modularity and reusability using innumerable modules
297 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
301 embeddable and extensible
303 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
304 L<perlguts>, and L<xsubpp>.
308 roll-your-own magic variables (including multiple simultaneous DBM
311 Described in L<perltie> and L<AnyDBM_File>.
315 subroutines can now be overridden, autoloaded, and prototyped
317 Described in L<perlsub>.
321 arbitrarily nested data structures and anonymous functions
323 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
327 object-oriented programming
329 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
334 support for light-weight processes (threads)
336 Described in L<perlthrtut> and L<threads>.
340 support for Unicode, internationalization, and localization
342 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
348 Described in L<perlsub>.
352 regular expression enhancements
354 Described in L<perlre>, with additional examples in L<perlop>.
358 enhanced debugger and interactive Perl environment,
359 with integrated editor support
361 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
365 POSIX 1003.1 compliant library
367 Described in L<POSIX>.
371 Okay, that's I<definitely> enough hype.
375 Perl is available for most operating systems, including virtually
376 all Unix-like platforms. See L<perlport/"Supported Platforms">
385 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
387 If your Perl success stories and testimonials may be of help to others
388 who wish to advocate the use of Perl in their applications,
389 or if you wish to simply express your gratitude to Larry and the
390 Perl developers, please write to perl-thanks@perl.org .
394 "@INC" locations of perl libraries
398 a2p awk to perl translator
399 s2p sed to perl translator
401 http://www.perl.org/ the Perl homepage
402 http://www.perl.com/ Perl articles (O'Reilly)
403 http://www.cpan.org/ the Comprehensive Perl Archive
404 http://www.pm.org/ the Perl Mongers
408 The C<use warnings> pragma (and the B<-w> switch) produces some
411 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
412 diagnostics> pragma automatically turns Perl's normally terse warnings
413 and errors into these longer forms.
415 Compilation errors will tell you the line number of the error, with an
416 indication of the next token or token type that was to be examined.
417 (In a script passed to Perl via B<-e> switches, each
418 B<-e> is counted as one line.)
420 Setuid scripts have additional constraints that can produce error
421 messages such as "Insecure dependency". See L<perlsec>.
423 Did we mention that you should definitely consider using the B<-w>
428 The B<-w> switch is not mandatory.
430 Perl is at the mercy of your machine's definitions of various
431 operations such as type casting, atof(), and floating-point
432 output with sprintf().
434 If your stdio requires a seek or eof between reads and writes on a
435 particular stream, so does Perl. (This doesn't apply to sysread()
438 While none of the built-in data types have any arbitrary size limits
439 (apart from memory size), there are still a few arbitrary limits: a
440 given variable name may not be longer than 251 characters. Line numbers
441 displayed by diagnostics are internally stored as short integers,
442 so they are limited to a maximum of 65535 (higher numbers usually being
443 affected by wraparound).
445 You may mail your bug reports (be sure to include full configuration
446 information as output by the myconfig program in the perl source
447 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
448 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
449 can be used to help mail in a bug report.
451 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
452 don't tell anyone I said that.
456 The Perl motto is "There's more than one way to do it." Divining
457 how many more is left as an exercise to the reader.
459 The three principal virtues of a programmer are Laziness,
460 Impatience, and Hubris. See the Camel Book for why.