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 perl591delta Perl changes in version 5.9.1
136 perl590delta Perl changes in version 5.9.0
137 perl583delta Perl changes in version 5.8.3
138 perl582delta Perl changes in version 5.8.2
139 perl581delta Perl changes in version 5.8.1
140 perl58delta Perl changes in version 5.8.0
141 perl573delta Perl changes in version 5.7.3
142 perl572delta Perl changes in version 5.7.2
143 perl571delta Perl changes in version 5.7.1
144 perl570delta Perl changes in version 5.7.0
145 perl561delta Perl changes in version 5.6.1
146 perl56delta Perl changes in version 5.6
147 perl5005delta Perl changes in version 5.005
148 perl5004delta Perl changes in version 5.004
150 perlartistic Perl Artistic License
151 perlgpl GNU General Public License
153 =head2 Language-Specific
155 perlcn Perl for Simplified Chinese (in EUC-CN)
156 perljp Perl for Japanese (in EUC-JP)
157 perlko Perl for Korean (in EUC-KR)
158 perltw Perl for Traditional Chinese (in Big5)
160 =head2 Platform-Specific
162 perlaix Perl notes for AIX
163 perlamiga Perl notes for AmigaOS
164 perlapollo Perl notes for Apollo DomainOS
165 perlbeos Perl notes for BeOS
166 perlbs2000 Perl notes for POSIX-BC BS2000
167 perlce Perl notes for WinCE
168 perlcygwin Perl notes for Cygwin
169 perldgux Perl notes for DG/UX
170 perldos Perl notes for DOS
171 perlepoc Perl notes for EPOC
172 perlfreebsd Perl notes for FreeBSD
173 perlhpux Perl notes for HP-UX
174 perlhurd Perl notes for Hurd
175 perlirix Perl notes for Irix
176 perlmachten Perl notes for Power MachTen
177 perlmacos Perl notes for Mac OS (Classic)
178 perlmacosx Perl notes for Mac OS X
179 perlmint Perl notes for MiNT
180 perlmpeix Perl notes for MPE/iX
181 perlnetware Perl notes for NetWare
182 perlos2 Perl notes for OS/2
183 perlos390 Perl notes for OS/390
184 perlos400 Perl notes for OS/400
185 perlplan9 Perl notes for Plan 9
186 perlqnx Perl notes for QNX
187 perlsolaris Perl notes for Solaris
188 perltru64 Perl notes for Tru64
189 perluts Perl notes for UTS
190 perlvmesa Perl notes for VM/ESA
191 perlvms Perl notes for VMS
192 perlvos Perl notes for Stratus VOS
193 perlwin32 Perl notes for Windows
196 By default, the manpages listed above are installed in the
197 F</usr/local/man/> directory.
199 Extensive additional documentation for Perl modules is available. The
200 default configuration for perl will place this additional documentation
201 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
202 subdirectory of the Perl library directory). Some of this additional
203 documentation is distributed standard with Perl, but you'll also find
204 documentation for third-party modules there.
206 You should be able to view Perl's documentation with your man(1)
207 program by including the proper directories in the appropriate start-up
208 files, or in the MANPATH environment variable. To find out where the
209 configuration has installed the manpages, type:
213 If the directories have a common stem, such as F</usr/local/man/man1>
214 and F</usr/local/man/man3>, you need only to add that stem
215 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
216 environment variable. If they do not share a stem, you'll have to add
219 If that doesn't work for some reason, you can still use the
220 supplied F<perldoc> script to view module information. You might
221 also look into getting a replacement man program.
223 If something strange has gone wrong with your program and you're not
224 sure where you should look for help, try the B<-w> switch first. It
225 will often point out exactly where the trouble is.
229 Perl is a language optimized for scanning arbitrary
230 text files, extracting information from those text files, and printing
231 reports based on that information. It's also a good language for many
232 system management tasks. The language is intended to be practical
233 (easy to use, efficient, complete) rather than beautiful (tiny,
236 Perl combines (in the author's opinion, anyway) some of the best
237 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
238 those languages should have little difficulty with it. (Language
239 historians will also note some vestiges of B<csh>, Pascal, and even
240 BASIC-PLUS.) Expression syntax corresponds closely to C
241 expression syntax. Unlike most Unix utilities, Perl does not
242 arbitrarily limit the size of your data--if you've got the memory,
243 Perl can slurp in your whole file as a single string. Recursion is of
244 unlimited depth. And the tables used by hashes (sometimes called
245 "associative arrays") grow as necessary to prevent degraded
246 performance. Perl can use sophisticated pattern matching techniques to
247 scan large amounts of data quickly. Although optimized for
248 scanning text, Perl can also deal with binary data, and can make dbm
249 files look like hashes. Setuid Perl scripts are safer than C programs
250 through a dataflow tracing mechanism that prevents many stupid
253 If you have a problem that would ordinarily use B<sed> or B<awk> or
254 B<sh>, but it exceeds their capabilities or must run a little faster,
255 and you don't want to write the silly thing in C, then Perl may be for
256 you. There are also translators to turn your B<sed> and B<awk>
257 scripts into Perl scripts.
259 But wait, there's more...
261 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
262 rewrite that provides the following additional benefits:
268 modularity and reusability using innumerable modules
270 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
274 embeddable and extensible
276 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
277 L<perlguts>, and L<xsubpp>.
281 roll-your-own magic variables (including multiple simultaneous DBM
284 Described in L<perltie> and L<AnyDBM_File>.
288 subroutines can now be overridden, autoloaded, and prototyped
290 Described in L<perlsub>.
294 arbitrarily nested data structures and anonymous functions
296 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
300 object-oriented programming
302 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
307 support for light-weight processes (threads)
309 Described in L<perlthrtut> and L<threads>.
313 support for Unicode, internationalization, and localization
315 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
321 Described in L<perlsub>.
325 regular expression enhancements
327 Described in L<perlre>, with additional examples in L<perlop>.
331 enhanced debugger and interactive Perl environment,
332 with integrated editor support
334 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
338 POSIX 1003.1 compliant library
340 Described in L<POSIX>.
344 Okay, that's I<definitely> enough hype.
348 Perl is available for most operating systems, including virtually
349 all Unix-like platforms. See L<perlport/"Supported Platforms">
358 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
360 If your Perl success stories and testimonials may be of help to others
361 who wish to advocate the use of Perl in their applications,
362 or if you wish to simply express your gratitude to Larry and the
363 Perl developers, please write to perl-thanks@perl.org .
367 "@INC" locations of perl libraries
371 a2p awk to perl translator
372 s2p sed to perl translator
374 http://www.perl.com/ the Perl Home Page
375 http://www.cpan.org/ the Comprehensive Perl Archive
376 http://www.perl.org/ Perl Mongers (Perl user groups)
380 The C<use warnings> pragma (and the B<-w> switch) produces some
383 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
384 diagnostics> pragma automatically turns Perl's normally terse warnings
385 and errors into these longer forms.
387 Compilation errors will tell you the line number of the error, with an
388 indication of the next token or token type that was to be examined.
389 (In a script passed to Perl via B<-e> switches, each
390 B<-e> is counted as one line.)
392 Setuid scripts have additional constraints that can produce error
393 messages such as "Insecure dependency". See L<perlsec>.
395 Did we mention that you should definitely consider using the B<-w>
400 The B<-w> switch is not mandatory.
402 Perl is at the mercy of your machine's definitions of various
403 operations such as type casting, atof(), and floating-point
404 output with sprintf().
406 If your stdio requires a seek or eof between reads and writes on a
407 particular stream, so does Perl. (This doesn't apply to sysread()
410 While none of the built-in data types have any arbitrary size limits
411 (apart from memory size), there are still a few arbitrary limits: a
412 given variable name may not be longer than 251 characters. Line numbers
413 displayed by diagnostics are internally stored as short integers,
414 so they are limited to a maximum of 65535 (higher numbers usually being
415 affected by wraparound).
417 You may mail your bug reports (be sure to include full configuration
418 information as output by the myconfig program in the perl source
419 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
420 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
421 can be used to help mail in a bug report.
423 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
424 don't tell anyone I said that.
428 The Perl motto is "There's more than one way to do it." Divining
429 how many more is left as an exercise to the reader.
431 The three principal virtues of a programmer are Laziness,
432 Impatience, and Hubris. See the Camel Book for why.