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 perl584delta Perl changes in version 5.8.4
138 perl583delta Perl changes in version 5.8.3
139 perl582delta Perl changes in version 5.8.2
140 perl581delta Perl changes in version 5.8.1
141 perl58delta Perl changes in version 5.8.0
142 perl573delta Perl changes in version 5.7.3
143 perl572delta Perl changes in version 5.7.2
144 perl571delta Perl changes in version 5.7.1
145 perl570delta Perl changes in version 5.7.0
146 perl561delta Perl changes in version 5.6.1
147 perl56delta Perl changes in version 5.6
148 perl5005delta Perl changes in version 5.005
149 perl5004delta Perl changes in version 5.004
151 perlartistic Perl Artistic License
152 perlgpl GNU General Public License
154 =head2 Language-Specific
156 perlcn Perl for Simplified Chinese (in EUC-CN)
157 perljp Perl for Japanese (in EUC-JP)
158 perlko Perl for Korean (in EUC-KR)
159 perltw Perl for Traditional Chinese (in Big5)
161 =head2 Platform-Specific
163 perlaix Perl notes for AIX
164 perlamiga Perl notes for AmigaOS
165 perlapollo Perl notes for Apollo DomainOS
166 perlbeos Perl notes for BeOS
167 perlbs2000 Perl notes for POSIX-BC BS2000
168 perlce Perl notes for WinCE
169 perlcygwin Perl notes for Cygwin
170 perldgux Perl notes for DG/UX
171 perldos Perl notes for DOS
172 perlepoc Perl notes for EPOC
173 perlfreebsd Perl notes for FreeBSD
174 perlhpux Perl notes for HP-UX
175 perlhurd Perl notes for Hurd
176 perlirix Perl notes for Irix
177 perlmachten Perl notes for Power MachTen
178 perlmacos Perl notes for Mac OS (Classic)
179 perlmacosx Perl notes for Mac OS X
180 perlmint Perl notes for MiNT
181 perlmpeix Perl notes for MPE/iX
182 perlnetware Perl notes for NetWare
183 perlos2 Perl notes for OS/2
184 perlos390 Perl notes for OS/390
185 perlos400 Perl notes for OS/400
186 perlplan9 Perl notes for Plan 9
187 perlqnx Perl notes for QNX
188 perlsolaris Perl notes for Solaris
189 perltru64 Perl notes for Tru64
190 perluts Perl notes for UTS
191 perlvmesa Perl notes for VM/ESA
192 perlvms Perl notes for VMS
193 perlvos Perl notes for Stratus VOS
194 perlwin32 Perl notes for Windows
197 By default, the manpages listed above are installed in the
198 F</usr/local/man/> directory.
200 Extensive additional documentation for Perl modules is available. The
201 default configuration for perl will place this additional documentation
202 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
203 subdirectory of the Perl library directory). Some of this additional
204 documentation is distributed standard with Perl, but you'll also find
205 documentation for third-party modules there.
207 You should be able to view Perl's documentation with your man(1)
208 program by including the proper directories in the appropriate start-up
209 files, or in the MANPATH environment variable. To find out where the
210 configuration has installed the manpages, type:
214 If the directories have a common stem, such as F</usr/local/man/man1>
215 and F</usr/local/man/man3>, you need only to add that stem
216 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
217 environment variable. If they do not share a stem, you'll have to add
220 If that doesn't work for some reason, you can still use the
221 supplied F<perldoc> script to view module information. You might
222 also look into getting a replacement man program.
224 If something strange has gone wrong with your program and you're not
225 sure where you should look for help, try the B<-w> switch first. It
226 will often point out exactly where the trouble is.
230 Perl is a language optimized for scanning arbitrary
231 text files, extracting information from those text files, and printing
232 reports based on that information. It's also a good language for many
233 system management tasks. The language is intended to be practical
234 (easy to use, efficient, complete) rather than beautiful (tiny,
237 Perl combines (in the author's opinion, anyway) some of the best
238 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
239 those languages should have little difficulty with it. (Language
240 historians will also note some vestiges of B<csh>, Pascal, and even
241 BASIC-PLUS.) Expression syntax corresponds closely to C
242 expression syntax. Unlike most Unix utilities, Perl does not
243 arbitrarily limit the size of your data--if you've got the memory,
244 Perl can slurp in your whole file as a single string. Recursion is of
245 unlimited depth. And the tables used by hashes (sometimes called
246 "associative arrays") grow as necessary to prevent degraded
247 performance. Perl can use sophisticated pattern matching techniques to
248 scan large amounts of data quickly. Although optimized for
249 scanning text, Perl can also deal with binary data, and can make dbm
250 files look like hashes. Setuid Perl scripts are safer than C programs
251 through a dataflow tracing mechanism that prevents many stupid
254 If you have a problem that would ordinarily use B<sed> or B<awk> or
255 B<sh>, but it exceeds their capabilities or must run a little faster,
256 and you don't want to write the silly thing in C, then Perl may be for
257 you. There are also translators to turn your B<sed> and B<awk>
258 scripts into Perl scripts.
260 But wait, there's more...
262 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
263 rewrite that provides the following additional benefits:
269 modularity and reusability using innumerable modules
271 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
275 embeddable and extensible
277 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
278 L<perlguts>, and L<xsubpp>.
282 roll-your-own magic variables (including multiple simultaneous DBM
285 Described in L<perltie> and L<AnyDBM_File>.
289 subroutines can now be overridden, autoloaded, and prototyped
291 Described in L<perlsub>.
295 arbitrarily nested data structures and anonymous functions
297 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
301 object-oriented programming
303 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
308 support for light-weight processes (threads)
310 Described in L<perlthrtut> and L<threads>.
314 support for Unicode, internationalization, and localization
316 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
322 Described in L<perlsub>.
326 regular expression enhancements
328 Described in L<perlre>, with additional examples in L<perlop>.
332 enhanced debugger and interactive Perl environment,
333 with integrated editor support
335 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
339 POSIX 1003.1 compliant library
341 Described in L<POSIX>.
345 Okay, that's I<definitely> enough hype.
349 Perl is available for most operating systems, including virtually
350 all Unix-like platforms. See L<perlport/"Supported Platforms">
359 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
361 If your Perl success stories and testimonials may be of help to others
362 who wish to advocate the use of Perl in their applications,
363 or if you wish to simply express your gratitude to Larry and the
364 Perl developers, please write to perl-thanks@perl.org .
368 "@INC" locations of perl libraries
372 a2p awk to perl translator
373 s2p sed to perl translator
375 http://www.perl.com/ the Perl Home Page
376 http://www.cpan.org/ the Comprehensive Perl Archive
377 http://www.perl.org/ Perl Mongers (Perl user groups)
381 The C<use warnings> pragma (and the B<-w> switch) produces some
384 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
385 diagnostics> pragma automatically turns Perl's normally terse warnings
386 and errors into these longer forms.
388 Compilation errors will tell you the line number of the error, with an
389 indication of the next token or token type that was to be examined.
390 (In a script passed to Perl via B<-e> switches, each
391 B<-e> is counted as one line.)
393 Setuid scripts have additional constraints that can produce error
394 messages such as "Insecure dependency". See L<perlsec>.
396 Did we mention that you should definitely consider using the B<-w>
401 The B<-w> switch is not mandatory.
403 Perl is at the mercy of your machine's definitions of various
404 operations such as type casting, atof(), and floating-point
405 output with sprintf().
407 If your stdio requires a seek or eof between reads and writes on a
408 particular stream, so does Perl. (This doesn't apply to sysread()
411 While none of the built-in data types have any arbitrary size limits
412 (apart from memory size), there are still a few arbitrary limits: a
413 given variable name may not be longer than 251 characters. Line numbers
414 displayed by diagnostics are internally stored as short integers,
415 so they are limited to a maximum of 65535 (higher numbers usually being
416 affected by wraparound).
418 You may mail your bug reports (be sure to include full configuration
419 information as output by the myconfig program in the perl source
420 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
421 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
422 can be used to help mail in a bug report.
424 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
425 don't tell anyone I said that.
429 The Perl motto is "There's more than one way to do it." Divining
430 how many more is left as an exercise to the reader.
432 The three principal virtues of a programmer are Laziness,
433 Impatience, and Hubris. See the Camel Book for why.