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 perlpod Perl plain old documentation
66 perlpodspec Perl plain old documentation format specification
67 perlrun Perl execution and options
68 perldiag Perl diagnostic messages
69 perllexwarn Perl warnings and their control
70 perldebug Perl debugging
71 perlvar Perl predefined variables
72 perlre Perl regular expressions, the rest of the story
73 perlref Perl references, the rest of the story
76 perltie Perl objects hidden behind simple variables
77 perldbmfilter Perl DBM filters
79 perlipc Perl interprocess communication
80 perlfork Perl fork() information
81 perlnumber Perl number semantics
83 perlthrtut Perl threads tutorial
84 perlothrtut Old Perl threads tutorial
86 perlport Perl portability guide
87 perllocale Perl locale support
88 perluniintro Perl Unicode introduction
89 perlunicode Perl Unicode support
90 perlebcdic Considerations for running Perl on EBCDIC platforms
94 perlmod Perl modules: how they work
95 perlmodlib Perl modules: how to write and use
96 perlmodstyle Perl modules: how to write modules with style
97 perlmodinstall Perl modules: how to install from CPAN
98 perlnewmod Perl modules: preparing a new module for distribution
100 perlutil utilities packaged with the Perl distribution
102 perlcompile Perl compiler suite intro
104 perlfilter Perl source filters
106 =head2 Internals and C Language Interface
108 perlembed Perl ways to embed perl in your C or C++ application
109 perldebguts Perl debugging guts and tips
110 perlxstut Perl XS tutorial
111 perlxs Perl XS application programming interface
112 perlclib Internal replacements for standard C library functions
113 perlguts Perl internal functions for those doing extensions
114 perlcall Perl calling conventions from C
116 perlapi Perl API listing (autogenerated)
117 perlintern Perl internal functions (autogenerated)
118 perliol C API for Perl's implementation of IO in Layers
119 perlapio Perl internal IO abstraction interface
121 perlhack Perl hackers guide
125 perlbook Perl book information
126 perltodo Perl things to do
128 perlhist Perl history records
129 perldelta Perl changes since previous version
130 perl572delta Perl changes in version 5.7.2
131 perl571delta Perl changes in version 5.7.1
132 perl570delta Perl changes in version 5.7.0
133 perl56delta Perl changes in version 5.6
134 perl5005delta Perl changes in version 5.005
135 perl5004delta Perl changes in version 5.004
137 =head2 Platform-Specific
139 perlaix Perl notes for AIX
140 perlamiga Perl notes for AmigaOS
141 perlapollo Perl notes for Apollo DomainOS
142 perlbeos Perl notes for BeOS
143 perlbs2000 Perl notes for POSIX-BC BS2000
144 perlce Perl notes for WinCE
145 perlcygwin Perl notes for Cygwin
146 perldgux Perl notes for DG/UX
147 perldos Perl notes for DOS
148 perlepoc Perl notes for EPOC
149 perlhpux Perl notes for HP-UX
150 perlhurd Perl notes for Hurd
151 perlmachten Perl notes for Power MachTen
152 perlmacos Perl notes for Mac OS (Classic)
153 perlmint Perl notes for MiNT
154 perlmpeix Perl notes for MPE/iX
155 perlnetware Perl notes for NetWare
156 perlos2 Perl notes for OS/2
157 perlos390 Perl notes for OS/390
158 perlplan9 Perl notes for Plan 9
159 perlqnx Perl notes for QNX
160 perlsolaris Perl notes for Solaris
161 perltru64 Perl notes for Tru64
162 perluts Perl notes for UTS
163 perlvmesa Perl notes for VM/ESA
164 perlvms Perl notes for VMS
165 perlvos Perl notes for Stratus VOS
166 perlwin32 Perl notes for Windows
169 By default, the manpages listed above are installed in the
170 F</usr/local/man/> directory.
172 Extensive additional documentation for Perl modules is available. The
173 default configuration for perl will place this additional documentation
174 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
175 subdirectory of the Perl library directory). Some of this additional
176 documentation is distributed standard with Perl, but you'll also find
177 documentation for third-party modules there.
179 You should be able to view Perl's documentation with your man(1)
180 program by including the proper directories in the appropriate start-up
181 files, or in the MANPATH environment variable. To find out where the
182 configuration has installed the manpages, type:
186 If the directories have a common stem, such as F</usr/local/man/man1>
187 and F</usr/local/man/man3>, you need only to add that stem
188 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
189 environment variable. If they do not share a stem, you'll have to add
192 If that doesn't work for some reason, you can still use the
193 supplied F<perldoc> script to view module information. You might
194 also look into getting a replacement man program.
196 If something strange has gone wrong with your program and you're not
197 sure where you should look for help, try the B<-w> switch first. It
198 will often point out exactly where the trouble is.
202 Perl is a language optimized for scanning arbitrary
203 text files, extracting information from those text files, and printing
204 reports based on that information. It's also a good language for many
205 system management tasks. The language is intended to be practical
206 (easy to use, efficient, complete) rather than beautiful (tiny,
209 Perl combines (in the author's opinion, anyway) some of the best
210 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
211 those languages should have little difficulty with it. (Language
212 historians will also note some vestiges of B<csh>, Pascal, and even
213 BASIC-PLUS.) Expression syntax corresponds closely to C
214 expression syntax. Unlike most Unix utilities, Perl does not
215 arbitrarily limit the size of your data--if you've got the memory,
216 Perl can slurp in your whole file as a single string. Recursion is of
217 unlimited depth. And the tables used by hashes (sometimes called
218 "associative arrays") grow as necessary to prevent degraded
219 performance. Perl can use sophisticated pattern matching techniques to
220 scan large amounts of data quickly. Although optimized for
221 scanning text, Perl can also deal with binary data, and can make dbm
222 files look like hashes. Setuid Perl scripts are safer than C programs
223 through a dataflow tracing mechanism that prevents many stupid
226 If you have a problem that would ordinarily use B<sed> or B<awk> or
227 B<sh>, but it exceeds their capabilities or must run a little faster,
228 and you don't want to write the silly thing in C, then Perl may be for
229 you. There are also translators to turn your B<sed> and B<awk>
230 scripts into Perl scripts.
232 But wait, there's more...
234 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
235 rewrite that provides the following additional benefits:
241 modularity and reusability using innumerable modules
243 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
247 embeddable and extensible
249 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
250 L<perlguts>, and L<xsubpp>.
254 roll-your-own magic variables (including multiple simultaneous DBM implementations)
256 Described in L<perltie> and L<AnyDBM_File>.
260 subroutines can now be overridden, autoloaded, and prototyped
262 Described in L<perlsub>.
266 arbitrarily nested data structures and anonymous functions
268 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
272 object-oriented programming
274 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
279 compilability into C code or Perl bytecode
281 Described in L<B> and L<B::Bytecode>.
285 support for light-weight processes (threads)
287 Described in L<perlthrtut> and L<Thread>.
291 support for internationalization, localization, and Unicode
293 Described in L<perllocale> and L<utf8>.
299 Described in L<perlsub>.
303 regular expression enhancements
305 Described in L<perlre>, with additional examples in L<perlop>.
309 enhanced debugger and interactive Perl environment,
310 with integrated editor support
312 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
316 POSIX 1003.1 compliant library
318 Described in L<POSIX>.
322 Okay, that's I<definitely> enough hype.
326 Perl is available for most operating systems, including virtually
327 all Unix-like platforms. See L<perlport/"Supported Platforms">
336 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
338 If your Perl success stories and testimonials may be of help to others
339 who wish to advocate the use of Perl in their applications,
340 or if you wish to simply express your gratitude to Larry and the
341 Perl developers, please write to perl-thanks@perl.org .
345 "@INC" locations of perl libraries
349 a2p awk to perl translator
350 s2p sed to perl translator
352 http://www.perl.com/ the Perl Home Page
353 http://www.cpan.org/ the Comprehensive Perl Archive
354 http://www.perl.org/ Perl Mongers (Perl user groups)
358 The C<use warnings> pragma (and the B<-w> switch) produces some
361 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
362 diagnostics> pragma automatically turns Perl's normally terse warnings
363 and errors into these longer forms.
365 Compilation errors will tell you the line number of the error, with an
366 indication of the next token or token type that was to be examined.
367 (In a script passed to Perl via B<-e> switches, each
368 B<-e> is counted as one line.)
370 Setuid scripts have additional constraints that can produce error
371 messages such as "Insecure dependency". See L<perlsec>.
373 Did we mention that you should definitely consider using the B<-w>
378 The B<-w> switch is not mandatory.
380 Perl is at the mercy of your machine's definitions of various
381 operations such as type casting, atof(), and floating-point
382 output with sprintf().
384 If your stdio requires a seek or eof between reads and writes on a
385 particular stream, so does Perl. (This doesn't apply to sysread()
388 While none of the built-in data types have any arbitrary size limits
389 (apart from memory size), there are still a few arbitrary limits: a
390 given variable name may not be longer than 251 characters. Line numbers
391 displayed by diagnostics are internally stored as short integers,
392 so they are limited to a maximum of 65535 (higher numbers usually being
393 affected by wraparound).
395 You may mail your bug reports (be sure to include full configuration
396 information as output by the myconfig program in the perl source
397 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
398 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
399 can be used to help mail in a bug report.
401 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
402 don't tell anyone I said that.
406 The Perl motto is "There's more than one way to do it." Divining
407 how many more is left as an exercise to the reader.
409 The three principal virtues of a programmer are Laziness,
410 Impatience, and Hubris. See the Camel Book for why.