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