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 perl592delta Perl changes in version 5.9.2
136 perl591delta Perl changes in version 5.9.1
137 perl590delta Perl changes in version 5.9.0
138 perl586delta Perl changes in version 5.8.6
139 perl585delta Perl changes in version 5.8.5
140 perl584delta Perl changes in version 5.8.4
141 perl583delta Perl changes in version 5.8.3
142 perl582delta Perl changes in version 5.8.2
143 perl581delta Perl changes in version 5.8.1
144 perl58delta Perl changes in version 5.8.0
145 perl573delta Perl changes in version 5.7.3
146 perl572delta Perl changes in version 5.7.2
147 perl571delta Perl changes in version 5.7.1
148 perl570delta Perl changes in version 5.7.0
149 perl561delta Perl changes in version 5.6.1
150 perl56delta Perl changes in version 5.6
151 perl5005delta Perl changes in version 5.005
152 perl5004delta Perl changes in version 5.004
154 perlartistic Perl Artistic License
155 perlgpl GNU General Public License
157 =head2 Language-Specific
159 perlcn Perl for Simplified Chinese (in EUC-CN)
160 perljp Perl for Japanese (in EUC-JP)
161 perlko Perl for Korean (in EUC-KR)
162 perltw Perl for Traditional Chinese (in Big5)
164 =head2 Platform-Specific
166 perlaix Perl notes for AIX
167 perlamiga Perl notes for AmigaOS
168 perlapollo Perl notes for Apollo DomainOS
169 perlbeos Perl notes for BeOS
170 perlbs2000 Perl notes for POSIX-BC BS2000
171 perlce Perl notes for WinCE
172 perlcygwin Perl notes for Cygwin
173 perldgux Perl notes for DG/UX
174 perldos Perl notes for DOS
175 perlepoc Perl notes for EPOC
176 perlfreebsd Perl notes for FreeBSD
177 perlhpux Perl notes for HP-UX
178 perlhurd Perl notes for Hurd
179 perlirix Perl notes for Irix
180 perlmachten Perl notes for Power MachTen
181 perlmacos Perl notes for Mac OS (Classic)
182 perlmacosx Perl notes for Mac OS X
183 perlmint Perl notes for MiNT
184 perlmpeix Perl notes for MPE/iX
185 perlnetware Perl notes for NetWare
186 perlos2 Perl notes for OS/2
187 perlos390 Perl notes for OS/390
188 perlos400 Perl notes for OS/400
189 perlplan9 Perl notes for Plan 9
190 perlqnx Perl notes for QNX
191 perlsolaris Perl notes for Solaris
192 perlsymbian Perl notes for Symbian
193 perltru64 Perl notes for Tru64
194 perluts Perl notes for UTS
195 perlvmesa Perl notes for VM/ESA
196 perlvms Perl notes for VMS
197 perlvos Perl notes for Stratus VOS
198 perlwin32 Perl notes for Windows
201 By default, the manpages listed above are installed in the
202 F</usr/local/man/> directory.
204 Extensive additional documentation for Perl modules is available. The
205 default configuration for perl will place this additional documentation
206 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
207 subdirectory of the Perl library directory). Some of this additional
208 documentation is distributed standard with Perl, but you'll also find
209 documentation for third-party modules there.
211 You should be able to view Perl's documentation with your man(1)
212 program by including the proper directories in the appropriate start-up
213 files, or in the MANPATH environment variable. To find out where the
214 configuration has installed the manpages, type:
218 If the directories have a common stem, such as F</usr/local/man/man1>
219 and F</usr/local/man/man3>, you need only to add that stem
220 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
221 environment variable. If they do not share a stem, you'll have to add
224 If that doesn't work for some reason, you can still use the
225 supplied F<perldoc> script to view module information. You might
226 also look into getting a replacement man program.
228 If something strange has gone wrong with your program and you're not
229 sure where you should look for help, try the B<-w> switch first. It
230 will often point out exactly where the trouble is.
234 Perl is a language optimized for scanning arbitrary
235 text files, extracting information from those text files, and printing
236 reports based on that information. It's also a good language for many
237 system management tasks. The language is intended to be practical
238 (easy to use, efficient, complete) rather than beautiful (tiny,
241 Perl combines (in the author's opinion, anyway) some of the best
242 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
243 those languages should have little difficulty with it. (Language
244 historians will also note some vestiges of B<csh>, Pascal, and even
245 BASIC-PLUS.) Expression syntax corresponds closely to C
246 expression syntax. Unlike most Unix utilities, Perl does not
247 arbitrarily limit the size of your data--if you've got the memory,
248 Perl can slurp in your whole file as a single string. Recursion is of
249 unlimited depth. And the tables used by hashes (sometimes called
250 "associative arrays") grow as necessary to prevent degraded
251 performance. Perl can use sophisticated pattern matching techniques to
252 scan large amounts of data quickly. Although optimized for
253 scanning text, Perl can also deal with binary data, and can make dbm
254 files look like hashes. Setuid Perl scripts are safer than C programs
255 through a dataflow tracing mechanism that prevents many stupid
258 If you have a problem that would ordinarily use B<sed> or B<awk> or
259 B<sh>, but it exceeds their capabilities or must run a little faster,
260 and you don't want to write the silly thing in C, then Perl may be for
261 you. There are also translators to turn your B<sed> and B<awk>
262 scripts into Perl scripts.
264 But wait, there's more...
266 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
267 rewrite that provides the following additional benefits:
273 modularity and reusability using innumerable modules
275 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
279 embeddable and extensible
281 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
282 L<perlguts>, and L<xsubpp>.
286 roll-your-own magic variables (including multiple simultaneous DBM
289 Described in L<perltie> and L<AnyDBM_File>.
293 subroutines can now be overridden, autoloaded, and prototyped
295 Described in L<perlsub>.
299 arbitrarily nested data structures and anonymous functions
301 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
305 object-oriented programming
307 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
312 support for light-weight processes (threads)
314 Described in L<perlthrtut> and L<threads>.
318 support for Unicode, internationalization, and localization
320 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
326 Described in L<perlsub>.
330 regular expression enhancements
332 Described in L<perlre>, with additional examples in L<perlop>.
336 enhanced debugger and interactive Perl environment,
337 with integrated editor support
339 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
343 POSIX 1003.1 compliant library
345 Described in L<POSIX>.
349 Okay, that's I<definitely> enough hype.
353 Perl is available for most operating systems, including virtually
354 all Unix-like platforms. See L<perlport/"Supported Platforms">
363 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
365 If your Perl success stories and testimonials may be of help to others
366 who wish to advocate the use of Perl in their applications,
367 or if you wish to simply express your gratitude to Larry and the
368 Perl developers, please write to perl-thanks@perl.org .
372 "@INC" locations of perl libraries
376 a2p awk to perl translator
377 s2p sed to perl translator
379 http://www.perl.org/ the Perl homepage
380 http://www.perl.com/ Perl articles (O'Reilly Media)
381 http://www.cpan.org/ the Comprehensive Perl Archive
382 http://www.pm.org/ the Perl Mongers
386 The C<use warnings> pragma (and the B<-w> switch) produces some
389 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
390 diagnostics> pragma automatically turns Perl's normally terse warnings
391 and errors into these longer forms.
393 Compilation errors will tell you the line number of the error, with an
394 indication of the next token or token type that was to be examined.
395 (In a script passed to Perl via B<-e> switches, each
396 B<-e> is counted as one line.)
398 Setuid scripts have additional constraints that can produce error
399 messages such as "Insecure dependency". See L<perlsec>.
401 Did we mention that you should definitely consider using the B<-w>
406 The B<-w> switch is not mandatory.
408 Perl is at the mercy of your machine's definitions of various
409 operations such as type casting, atof(), and floating-point
410 output with sprintf().
412 If your stdio requires a seek or eof between reads and writes on a
413 particular stream, so does Perl. (This doesn't apply to sysread()
416 While none of the built-in data types have any arbitrary size limits
417 (apart from memory size), there are still a few arbitrary limits: a
418 given variable name may not be longer than 251 characters. Line numbers
419 displayed by diagnostics are internally stored as short integers,
420 so they are limited to a maximum of 65535 (higher numbers usually being
421 affected by wraparound).
423 You may mail your bug reports (be sure to include full configuration
424 information as output by the myconfig program in the perl source
425 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
426 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
427 can be used to help mail in a bug report.
429 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
430 don't tell anyone I said that.
434 The Perl motto is "There's more than one way to do it." Divining
435 how many more is left as an exercise to the reader.
437 The three principal virtues of a programmer are Laziness,
438 Impatience, and Hubris. See the Camel Book for why.