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