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 perltrap Perl traps for the unwary
44 perldebtut Perl debugging tutorial
46 perlfaq Perl frequently asked questions
47 perlfaq1 General Questions About Perl
48 perlfaq2 Obtaining and Learning about Perl
49 perlfaq3 Programming Tools
50 perlfaq4 Data Manipulation
51 perlfaq5 Files and Formats
53 perlfaq7 Perl Language Issues
54 perlfaq8 System Interaction
57 =head2 Reference Manual
60 perldata Perl data structures
61 perlop Perl operators and precedence
62 perlsub Perl subroutines
63 perlfunc Perl built-in functions
64 perlopentut Perl open() tutorial
65 perlpacktut Perl open() tutorial
66 perlpod Perl plain old documentation
67 perlpodspec Perl plain old documentation format specification
68 perlrun Perl execution and options
69 perldiag Perl diagnostic messages
70 perllexwarn Perl warnings and their control
71 perldebug Perl debugging
72 perlvar Perl predefined variables
73 perlre Perl regular expressions, the rest of the story
74 perlref Perl references, the rest of the story
77 perltie Perl objects hidden behind simple variables
78 perldbmfilter Perl DBM filters
80 perlipc Perl interprocess communication
81 perlfork Perl fork() information
82 perlnumber Perl number semantics
84 perlthrtut Perl threads tutorial
85 perlothrtut Old Perl threads tutorial
87 perlport Perl portability guide
88 perllocale Perl locale support
89 perluniintro Perl Unicode introduction
90 perlunicode Perl Unicode support
91 perlebcdic Considerations for running Perl on EBCDIC platforms
95 perlmod Perl modules: how they work
96 perlmodlib Perl modules: how to write and use
97 perlmodstyle Perl modules: how to write modules with style
98 perlmodinstall Perl modules: how to install from CPAN
99 perlnewmod Perl modules: preparing a new module for distribution
101 perlutil utilities packaged with the Perl distribution
103 perlcompile Perl compiler suite intro
105 perlfilter Perl source filters
107 =head2 Internals and C Language Interface
109 perlembed Perl ways to embed perl in your C or C++ application
110 perldebguts Perl debugging guts and tips
111 perlxstut Perl XS tutorial
112 perlxs Perl XS application programming interface
113 perlclib Internal replacements for standard C library functions
114 perlguts Perl internal functions for those doing extensions
115 perlcall Perl calling conventions from C
117 perlapi Perl API listing (autogenerated)
118 perlintern Perl internal functions (autogenerated)
119 perliol C API for Perl's implementation of IO in Layers
120 perlapio Perl internal IO abstraction interface
122 perlhack Perl hackers guide
126 perlbook Perl book information
127 perltodo Perl things to do
129 perlhist Perl history records
130 perldelta Perl changes since previous version
131 perl572delta Perl changes in version 5.7.2
132 perl571delta Perl changes in version 5.7.1
133 perl570delta Perl changes in version 5.7.0
134 perl561delta Perl changes in version 5.6.1
135 perl56delta Perl changes in version 5.6
136 perl5005delta Perl changes in version 5.005
137 perl5004delta Perl changes in version 5.004
139 =head2 Language-Specific
141 perlcn Perl for Simplified Chinese (in EUC-CN)
142 perljp Perl for Japanese (in EUC-JP)
143 perlko Perl for Korean (in EUC-KR)
144 perltw Perl for Traditional Chinese (in Big5)
146 =head2 Platform-Specific
148 perlaix Perl notes for AIX
149 perlamiga Perl notes for AmigaOS
150 perlapollo Perl notes for Apollo DomainOS
151 perlbeos Perl notes for BeOS
152 perlbs2000 Perl notes for POSIX-BC BS2000
153 perlce Perl notes for WinCE
154 perlcygwin Perl notes for Cygwin
155 perldgux Perl notes for DG/UX
156 perldos Perl notes for DOS
157 perlepoc Perl notes for EPOC
158 perlhpux Perl notes for HP-UX
159 perlhurd Perl notes for Hurd
160 perlmachten Perl notes for Power MachTen
161 perlmacos Perl notes for Mac OS (Classic)
162 perlmint Perl notes for MiNT
163 perlmpeix Perl notes for MPE/iX
164 perlnetware Perl notes for NetWare
165 perlos2 Perl notes for OS/2
166 perlos390 Perl notes for OS/390
167 perlplan9 Perl notes for Plan 9
168 perlqnx Perl notes for QNX
169 perlsolaris Perl notes for Solaris
170 perltru64 Perl notes for Tru64
171 perluts Perl notes for UTS
172 perlvmesa Perl notes for VM/ESA
173 perlvms Perl notes for VMS
174 perlvos Perl notes for Stratus VOS
175 perlwin32 Perl notes for Windows
178 By default, the manpages listed above are installed in the
179 F</usr/local/man/> directory.
181 Extensive additional documentation for Perl modules is available. The
182 default configuration for perl will place this additional documentation
183 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
184 subdirectory of the Perl library directory). Some of this additional
185 documentation is distributed standard with Perl, but you'll also find
186 documentation for third-party modules there.
188 You should be able to view Perl's documentation with your man(1)
189 program by including the proper directories in the appropriate start-up
190 files, or in the MANPATH environment variable. To find out where the
191 configuration has installed the manpages, type:
195 If the directories have a common stem, such as F</usr/local/man/man1>
196 and F</usr/local/man/man3>, you need only to add that stem
197 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
198 environment variable. If they do not share a stem, you'll have to add
201 If that doesn't work for some reason, you can still use the
202 supplied F<perldoc> script to view module information. You might
203 also look into getting a replacement man program.
205 If something strange has gone wrong with your program and you're not
206 sure where you should look for help, try the B<-w> switch first. It
207 will often point out exactly where the trouble is.
211 Perl is a language optimized for scanning arbitrary
212 text files, extracting information from those text files, and printing
213 reports based on that information. It's also a good language for many
214 system management tasks. The language is intended to be practical
215 (easy to use, efficient, complete) rather than beautiful (tiny,
218 Perl combines (in the author's opinion, anyway) some of the best
219 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
220 those languages should have little difficulty with it. (Language
221 historians will also note some vestiges of B<csh>, Pascal, and even
222 BASIC-PLUS.) Expression syntax corresponds closely to C
223 expression syntax. Unlike most Unix utilities, Perl does not
224 arbitrarily limit the size of your data--if you've got the memory,
225 Perl can slurp in your whole file as a single string. Recursion is of
226 unlimited depth. And the tables used by hashes (sometimes called
227 "associative arrays") grow as necessary to prevent degraded
228 performance. Perl can use sophisticated pattern matching techniques to
229 scan large amounts of data quickly. Although optimized for
230 scanning text, Perl can also deal with binary data, and can make dbm
231 files look like hashes. Setuid Perl scripts are safer than C programs
232 through a dataflow tracing mechanism that prevents many stupid
235 If you have a problem that would ordinarily use B<sed> or B<awk> or
236 B<sh>, but it exceeds their capabilities or must run a little faster,
237 and you don't want to write the silly thing in C, then Perl may be for
238 you. There are also translators to turn your B<sed> and B<awk>
239 scripts into Perl scripts.
241 But wait, there's more...
243 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
244 rewrite that provides the following additional benefits:
250 modularity and reusability using innumerable modules
252 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
256 embeddable and extensible
258 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
259 L<perlguts>, and L<xsubpp>.
263 roll-your-own magic variables (including multiple simultaneous DBM implementations)
265 Described in L<perltie> and L<AnyDBM_File>.
269 subroutines can now be overridden, autoloaded, and prototyped
271 Described in L<perlsub>.
275 arbitrarily nested data structures and anonymous functions
277 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
281 object-oriented programming
283 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
288 compilability into C code or Perl bytecode
290 Described in L<B> and L<B::Bytecode>.
294 support for light-weight processes (threads)
296 Described in L<perlthrtut> and L<Thread>.
300 support for internationalization, localization, and Unicode
302 Described in L<perllocale> and L<utf8>.
308 Described in L<perlsub>.
312 regular expression enhancements
314 Described in L<perlre>, with additional examples in L<perlop>.
318 enhanced debugger and interactive Perl environment,
319 with integrated editor support
321 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
325 POSIX 1003.1 compliant library
327 Described in L<POSIX>.
331 Okay, that's I<definitely> enough hype.
335 Perl is available for most operating systems, including virtually
336 all Unix-like platforms. See L<perlport/"Supported Platforms">
345 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
347 If your Perl success stories and testimonials may be of help to others
348 who wish to advocate the use of Perl in their applications,
349 or if you wish to simply express your gratitude to Larry and the
350 Perl developers, please write to perl-thanks@perl.org .
354 "@INC" locations of perl libraries
358 a2p awk to perl translator
359 s2p sed to perl translator
361 http://www.perl.com/ the Perl Home Page
362 http://www.cpan.org/ the Comprehensive Perl Archive
363 http://www.perl.org/ Perl Mongers (Perl user groups)
367 The C<use warnings> pragma (and the B<-w> switch) produces some
370 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
371 diagnostics> pragma automatically turns Perl's normally terse warnings
372 and errors into these longer forms.
374 Compilation errors will tell you the line number of the error, with an
375 indication of the next token or token type that was to be examined.
376 (In a script passed to Perl via B<-e> switches, each
377 B<-e> is counted as one line.)
379 Setuid scripts have additional constraints that can produce error
380 messages such as "Insecure dependency". See L<perlsec>.
382 Did we mention that you should definitely consider using the B<-w>
387 The B<-w> switch is not mandatory.
389 Perl is at the mercy of your machine's definitions of various
390 operations such as type casting, atof(), and floating-point
391 output with sprintf().
393 If your stdio requires a seek or eof between reads and writes on a
394 particular stream, so does Perl. (This doesn't apply to sysread()
397 While none of the built-in data types have any arbitrary size limits
398 (apart from memory size), there are still a few arbitrary limits: a
399 given variable name may not be longer than 251 characters. Line numbers
400 displayed by diagnostics are internally stored as short integers,
401 so they are limited to a maximum of 65535 (higher numbers usually being
402 affected by wraparound).
404 You may mail your bug reports (be sure to include full configuration
405 information as output by the myconfig program in the perl source
406 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
407 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
408 can be used to help mail in a bug report.
410 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
411 don't tell anyone I said that.
415 The Perl motto is "There's more than one way to do it." Divining
416 how many more is left as an exercise to the reader.
418 The three principal virtues of a programmer are Laziness,
419 Impatience, and Hubris. See the Camel Book for why.