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