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