3 perl - Practical Extraction and Report Language
7 B<perl> S<[ B<-sTuU> ]> S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
8 S<[ B<-cw> ] [ B<-d>[:I<debugger>] ] [ B<-D>[I<number/list>] ]>
9 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal>] ]>
10 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ]>
11 S<[ B<-P> ]> S<[ B<-S> ]> S<[ B<-x>[I<dir>] ]>
12 S<[ B<-i>[I<extension>] ]> S<[ B<-e> I<'command'> ]
13 [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
15 If you're new to Perl, you should start with L<perlintro>, which is a
16 general intro for beginners and provides some background to help you
17 navigate the rest of Perl's extensive documentation.
19 For ease of access, the Perl manual has been split up into several sections.
23 perl Perl overview (this section)
24 perlintro Perl introduction for beginners
25 perltoc Perl documentation table of contents
29 perlreftut Perl references short introduction
30 perldsc Perl data structures intro
31 perllol Perl data structures: arrays of arrays
33 perlrequick Perl regular expressions quick start
34 perlretut Perl regular expressions tutorial
36 perlboot Perl OO tutorial for beginners
37 perltoot Perl OO tutorial, part 1
38 perltooc Perl OO tutorial, part 2
39 perlbot Perl OO tricks and examples
41 perlstyle Perl style guide
43 perlcheat Perl cheat sheet
44 perltrap Perl traps for the unwary
45 perldebtut Perl debugging tutorial
47 perlfaq Perl frequently asked questions
48 perlfaq1 General Questions About Perl
49 perlfaq2 Obtaining and Learning about Perl
50 perlfaq3 Programming Tools
51 perlfaq4 Data Manipulation
52 perlfaq5 Files and Formats
54 perlfaq7 Perl Language Issues
55 perlfaq8 System Interaction
58 =head2 Reference Manual
61 perldata Perl data structures
62 perlop Perl operators and precedence
63 perlsub Perl subroutines
64 perlfunc Perl built-in functions
65 perlopentut Perl open() tutorial
66 perlpacktut Perl pack() and unpack() tutorial
67 perlpod Perl plain old documentation
68 perlpodspec Perl plain old documentation format specification
69 perlrun Perl execution and options
70 perldiag Perl diagnostic messages
71 perllexwarn Perl warnings and their control
72 perldebug Perl debugging
73 perlvar Perl predefined variables
74 perlre Perl regular expressions, the rest of the story
75 perlreref Perl regular expressions quick reference
76 perlref Perl references, the rest of the story
79 perltie Perl objects hidden behind simple variables
80 perldbmfilter Perl DBM filters
82 perlipc Perl interprocess communication
83 perlfork Perl fork() information
84 perlnumber Perl number semantics
86 perlthrtut Perl threads tutorial
87 perlothrtut Old Perl threads tutorial
89 perlport Perl portability guide
90 perllocale Perl locale support
91 perluniintro Perl Unicode introduction
92 perlunicode Perl Unicode support
93 perlebcdic Considerations for running Perl on EBCDIC platforms
97 perlmod Perl modules: how they work
98 perlmodlib Perl modules: how to write and use
99 perlmodstyle Perl modules: how to write modules with style
100 perlmodinstall Perl modules: how to install from CPAN
101 perlnewmod Perl modules: preparing a new module for distribution
103 perlutil utilities packaged with the Perl distribution
105 perlcompile Perl compiler suite intro
107 perlfilter Perl source filters
109 =head2 Internals and C Language Interface
111 perlembed Perl ways to embed perl in your C or C++ application
112 perldebguts Perl debugging guts and tips
113 perlxstut Perl XS tutorial
114 perlxs Perl XS application programming interface
115 perlclib Internal replacements for standard C library functions
116 perlguts Perl internal functions for those doing extensions
117 perlcall Perl calling conventions from C
119 perlapi Perl API listing (autogenerated)
120 perlintern Perl internal functions (autogenerated)
121 perliol C API for Perl's implementation of IO in Layers
122 perlapio Perl internal IO abstraction interface
124 perlhack Perl hackers guide
128 perlbook Perl book information
129 perltodo Perl things to do
131 perldoc Look up Perl documentation in Pod format
133 perlhist Perl history records
134 perldelta Perl changes since previous version
135 perl58delta Perl changes in version 5.8.0
136 perl573delta Perl changes in version 5.7.3
137 perl572delta Perl changes in version 5.7.2
138 perl571delta Perl changes in version 5.7.1
139 perl570delta Perl changes in version 5.7.0
140 perl561delta Perl changes in version 5.6.1
141 perl56delta Perl changes in version 5.6
142 perl5005delta Perl changes in version 5.005
143 perl5004delta Perl changes in version 5.004
145 perlartistic Perl Artistic License
146 perlgpl GNU General Public License
148 =head2 Language-Specific
150 perlcn Perl for Simplified Chinese (in EUC-CN)
151 perljp Perl for Japanese (in EUC-JP)
152 perlko Perl for Korean (in EUC-KR)
153 perltw Perl for Traditional Chinese (in Big5)
155 =head2 Platform-Specific
157 perlaix Perl notes for AIX
158 perlamiga Perl notes for AmigaOS
159 perlapollo Perl notes for Apollo DomainOS
160 perlbeos Perl notes for BeOS
161 perlbs2000 Perl notes for POSIX-BC BS2000
162 perlce Perl notes for WinCE
163 perlcygwin Perl notes for Cygwin
164 perldgux Perl notes for DG/UX
165 perldos Perl notes for DOS
166 perlepoc Perl notes for EPOC
167 perlfreebsd Perl notes for FreeBSD
168 perlhpux Perl notes for HP-UX
169 perlhurd Perl notes for Hurd
170 perlirix Perl notes for Irix
171 perlmachten Perl notes for Power MachTen
172 perlmacos Perl notes for Mac OS (Classic)
173 perlmacosx Perl notes for Mac OS X
174 perlmint Perl notes for MiNT
175 perlmpeix Perl notes for MPE/iX
176 perlnetware Perl notes for NetWare
177 perlos2 Perl notes for OS/2
178 perlos390 Perl notes for OS/390
179 perlos400 Perl notes for OS/400
180 perlplan9 Perl notes for Plan 9
181 perlqnx Perl notes for QNX
182 perlsolaris Perl notes for Solaris
183 perltru64 Perl notes for Tru64
184 perluts Perl notes for UTS
185 perlvmesa Perl notes for VM/ESA
186 perlvms Perl notes for VMS
187 perlvos Perl notes for Stratus VOS
188 perlwin32 Perl notes for Windows
191 By default, the manpages listed above are installed in the
192 F</usr/local/man/> directory.
194 Extensive additional documentation for Perl modules is available. The
195 default configuration for perl will place this additional documentation
196 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
197 subdirectory of the Perl library directory). Some of this additional
198 documentation is distributed standard with Perl, but you'll also find
199 documentation for third-party modules there.
201 You should be able to view Perl's documentation with your man(1)
202 program by including the proper directories in the appropriate start-up
203 files, or in the MANPATH environment variable. To find out where the
204 configuration has installed the manpages, type:
208 If the directories have a common stem, such as F</usr/local/man/man1>
209 and F</usr/local/man/man3>, you need only to add that stem
210 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
211 environment variable. If they do not share a stem, you'll have to add
214 If that doesn't work for some reason, you can still use the
215 supplied F<perldoc> script to view module information. You might
216 also look into getting a replacement man program.
218 If something strange has gone wrong with your program and you're not
219 sure where you should look for help, try the B<-w> switch first. It
220 will often point out exactly where the trouble is.
224 Perl is a language optimized for scanning arbitrary
225 text files, extracting information from those text files, and printing
226 reports based on that information. It's also a good language for many
227 system management tasks. The language is intended to be practical
228 (easy to use, efficient, complete) rather than beautiful (tiny,
231 Perl combines (in the author's opinion, anyway) some of the best
232 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
233 those languages should have little difficulty with it. (Language
234 historians will also note some vestiges of B<csh>, Pascal, and even
235 BASIC-PLUS.) Expression syntax corresponds closely to C
236 expression syntax. Unlike most Unix utilities, Perl does not
237 arbitrarily limit the size of your data--if you've got the memory,
238 Perl can slurp in your whole file as a single string. Recursion is of
239 unlimited depth. And the tables used by hashes (sometimes called
240 "associative arrays") grow as necessary to prevent degraded
241 performance. Perl can use sophisticated pattern matching techniques to
242 scan large amounts of data quickly. Although optimized for
243 scanning text, Perl can also deal with binary data, and can make dbm
244 files look like hashes. Setuid Perl scripts are safer than C programs
245 through a dataflow tracing mechanism that prevents many stupid
248 If you have a problem that would ordinarily use B<sed> or B<awk> or
249 B<sh>, but it exceeds their capabilities or must run a little faster,
250 and you don't want to write the silly thing in C, then Perl may be for
251 you. There are also translators to turn your B<sed> and B<awk>
252 scripts into Perl scripts.
254 But wait, there's more...
256 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
257 rewrite that provides the following additional benefits:
263 modularity and reusability using innumerable modules
265 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
269 embeddable and extensible
271 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
272 L<perlguts>, and L<xsubpp>.
276 roll-your-own magic variables (including multiple simultaneous DBM
279 Described in L<perltie> and L<AnyDBM_File>.
283 subroutines can now be overridden, autoloaded, and prototyped
285 Described in L<perlsub>.
289 arbitrarily nested data structures and anonymous functions
291 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
295 object-oriented programming
297 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
302 support for light-weight processes (threads)
304 Described in L<perlthrtut> and L<threads>.
308 support for Unicode, internationalization, and localization
310 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
316 Described in L<perlsub>.
320 regular expression enhancements
322 Described in L<perlre>, with additional examples in L<perlop>.
326 enhanced debugger and interactive Perl environment,
327 with integrated editor support
329 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
333 POSIX 1003.1 compliant library
335 Described in L<POSIX>.
339 Okay, that's I<definitely> enough hype.
343 Perl is available for most operating systems, including virtually
344 all Unix-like platforms. See L<perlport/"Supported Platforms">
353 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
355 If your Perl success stories and testimonials may be of help to others
356 who wish to advocate the use of Perl in their applications,
357 or if you wish to simply express your gratitude to Larry and the
358 Perl developers, please write to perl-thanks@perl.org .
362 "@INC" locations of perl libraries
366 a2p awk to perl translator
367 s2p sed to perl translator
369 http://www.perl.com/ the Perl Home Page
370 http://www.cpan.org/ the Comprehensive Perl Archive
371 http://www.perl.org/ Perl Mongers (Perl user groups)
375 The C<use warnings> pragma (and the B<-w> switch) produces some
378 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
379 diagnostics> pragma automatically turns Perl's normally terse warnings
380 and errors into these longer forms.
382 Compilation errors will tell you the line number of the error, with an
383 indication of the next token or token type that was to be examined.
384 (In a script passed to Perl via B<-e> switches, each
385 B<-e> is counted as one line.)
387 Setuid scripts have additional constraints that can produce error
388 messages such as "Insecure dependency". See L<perlsec>.
390 Did we mention that you should definitely consider using the B<-w>
395 The B<-w> switch is not mandatory.
397 Perl is at the mercy of your machine's definitions of various
398 operations such as type casting, atof(), and floating-point
399 output with sprintf().
401 If your stdio requires a seek or eof between reads and writes on a
402 particular stream, so does Perl. (This doesn't apply to sysread()
405 While none of the built-in data types have any arbitrary size limits
406 (apart from memory size), there are still a few arbitrary limits: a
407 given variable name may not be longer than 251 characters. Line numbers
408 displayed by diagnostics are internally stored as short integers,
409 so they are limited to a maximum of 65535 (higher numbers usually being
410 affected by wraparound).
412 You may mail your bug reports (be sure to include full configuration
413 information as output by the myconfig program in the perl source
414 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
415 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
416 can be used to help mail in a bug report.
418 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
419 don't tell anyone I said that.
423 The Perl motto is "There's more than one way to do it." Divining
424 how many more is left as an exercise to the reader.
426 The three principal virtues of a programmer are Laziness,
427 Impatience, and Hubris. See the Camel Book for why.