3 perl - Practical Extraction and Report Language
7 B<perl> S<[ B<-sTtuUWX> ]>
8 S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
9 S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
10 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
11 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]>
12 S<[ B<-A>[I<module>][=I<assertions>] ]>
13 S<[ B<-C [I<number/list>] >]>
17 S<[ B<-i>[I<extension>] ]>
18 S<[ B<-e> I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
20 If you're new to Perl, you should start with L<perlintro>, which is a
21 general intro for beginners and provides some background to help you
22 navigate the rest of Perl's extensive documentation.
24 For ease of access, the Perl manual has been split up into several sections.
28 perl Perl overview (this section)
29 perlintro Perl introduction for beginners
30 perltoc Perl documentation table of contents
34 perlreftut Perl references short introduction
35 perldsc Perl data structures intro
36 perllol Perl data structures: arrays of arrays
38 perlrequick Perl regular expressions quick start
39 perlretut Perl regular expressions tutorial
41 perlboot Perl OO tutorial for beginners
42 perltoot Perl OO tutorial, part 1
43 perltooc Perl OO tutorial, part 2
44 perlbot Perl OO tricks and examples
46 perlstyle Perl style guide
48 perlcheat Perl cheat sheet
49 perltrap Perl traps for the unwary
50 perldebtut Perl debugging tutorial
52 perlfaq Perl frequently asked questions
53 perlfaq1 General Questions About Perl
54 perlfaq2 Obtaining and Learning about Perl
55 perlfaq3 Programming Tools
56 perlfaq4 Data Manipulation
57 perlfaq5 Files and Formats
59 perlfaq7 Perl Language Issues
60 perlfaq8 System Interaction
63 =head2 Reference Manual
66 perldata Perl data structures
67 perlop Perl operators and precedence
68 perlsub Perl subroutines
69 perlfunc Perl built-in functions
70 perlopentut Perl open() tutorial
71 perlpacktut Perl pack() and unpack() tutorial
72 perlpod Perl plain old documentation
73 perlpodspec Perl plain old documentation format specification
74 perlrun Perl execution and options
75 perldiag Perl diagnostic messages
76 perllexwarn Perl warnings and their control
77 perldebug Perl debugging
78 perlvar Perl predefined variables
79 perlre Perl regular expressions, the rest of the story
80 perlreref Perl regular expressions quick reference
81 perlref Perl references, the rest of the story
84 perltie Perl objects hidden behind simple variables
85 perldbmfilter Perl DBM filters
87 perlipc Perl interprocess communication
88 perlfork Perl fork() information
89 perlnumber Perl number semantics
91 perlthrtut Perl threads tutorial
92 perlothrtut Old Perl threads tutorial
94 perlport Perl portability guide
95 perllocale Perl locale support
96 perluniintro Perl Unicode introduction
97 perlunicode Perl Unicode support
98 perlebcdic Considerations for running Perl on EBCDIC platforms
100 perlsec Perl security
102 perlmod Perl modules: how they work
103 perlmodlib Perl modules: how to write and use
104 perlmodstyle Perl modules: how to write modules with style
105 perlmodinstall Perl modules: how to install from CPAN
106 perlnewmod Perl modules: preparing a new module for distribution
108 perlutil utilities packaged with the Perl distribution
110 perlcompile Perl compiler suite intro
112 perlfilter Perl source filters
114 perlglossary Perl Glossary
116 =head2 Internals and C Language Interface
118 perlembed Perl ways to embed perl in your C or C++ application
119 perldebguts Perl debugging guts and tips
120 perlxstut Perl XS tutorial
121 perlxs Perl XS application programming interface
122 perlclib Internal replacements for standard C library functions
123 perlguts Perl internal functions for those doing extensions
124 perlcall Perl calling conventions from C
126 perlapi Perl API listing (autogenerated)
127 perlintern Perl internal functions (autogenerated)
128 perliol C API for Perl's implementation of IO in Layers
129 perlapio Perl internal IO abstraction interface
131 perlhack Perl hackers guide
135 perlbook Perl book information
136 perltodo Perl things to do
138 perldoc Look up Perl documentation in Pod format
140 perlhist Perl history records
141 perldelta Perl changes since previous version
142 perl592delta Perl changes in version 5.9.2
143 perl591delta Perl changes in version 5.9.1
144 perl590delta Perl changes in version 5.9.0
145 perl587delta Perl changes in version 5.8.7
146 perl586delta Perl changes in version 5.8.6
147 perl585delta Perl changes in version 5.8.5
148 perl584delta Perl changes in version 5.8.4
149 perl583delta Perl changes in version 5.8.3
150 perl582delta Perl changes in version 5.8.2
151 perl581delta Perl changes in version 5.8.1
152 perl58delta Perl changes in version 5.8.0
153 perl573delta Perl changes in version 5.7.3
154 perl572delta Perl changes in version 5.7.2
155 perl571delta Perl changes in version 5.7.1
156 perl570delta Perl changes in version 5.7.0
157 perl561delta Perl changes in version 5.6.1
158 perl56delta Perl changes in version 5.6
159 perl5005delta Perl changes in version 5.005
160 perl5004delta Perl changes in version 5.004
162 perlartistic Perl Artistic License
163 perlgpl GNU General Public License
165 =head2 Language-Specific
167 perlcn Perl for Simplified Chinese (in EUC-CN)
168 perljp Perl for Japanese (in EUC-JP)
169 perlko Perl for Korean (in EUC-KR)
170 perltw Perl for Traditional Chinese (in Big5)
172 =head2 Platform-Specific
174 perlaix Perl notes for AIX
175 perlamiga Perl notes for AmigaOS
176 perlapollo Perl notes for Apollo DomainOS
177 perlbeos Perl notes for BeOS
178 perlbs2000 Perl notes for POSIX-BC BS2000
179 perlce Perl notes for WinCE
180 perlcygwin Perl notes for Cygwin
181 perldgux Perl notes for DG/UX
182 perldos Perl notes for DOS
183 perlepoc Perl notes for EPOC
184 perlfreebsd Perl notes for FreeBSD
185 perlhpux Perl notes for HP-UX
186 perlhurd Perl notes for Hurd
187 perlirix Perl notes for Irix
188 perlmachten Perl notes for Power MachTen
189 perlmacos Perl notes for Mac OS (Classic)
190 perlmacosx Perl notes for Mac OS X
191 perlmint Perl notes for MiNT
192 perlmpeix Perl notes for MPE/iX
193 perlnetware Perl notes for NetWare
194 perlopenbsd Perl notes for OpenBSD
195 perlos2 Perl notes for OS/2
196 perlos390 Perl notes for OS/390
197 perlos400 Perl notes for OS/400
198 perlplan9 Perl notes for Plan 9
199 perlqnx Perl notes for QNX
200 perlsolaris Perl notes for Solaris
201 perlsymbian Perl notes for Symbian
202 perltru64 Perl notes for Tru64
203 perluts Perl notes for UTS
204 perlvmesa Perl notes for VM/ESA
205 perlvms Perl notes for VMS
206 perlvos Perl notes for Stratus VOS
207 perlwin32 Perl notes for Windows
210 By default, the manpages listed above are installed in the
211 F</usr/local/man/> directory.
213 Extensive additional documentation for Perl modules is available. The
214 default configuration for perl will place this additional documentation
215 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
216 subdirectory of the Perl library directory). Some of this additional
217 documentation is distributed standard with Perl, but you'll also find
218 documentation for third-party modules there.
220 You should be able to view Perl's documentation with your man(1)
221 program by including the proper directories in the appropriate start-up
222 files, or in the MANPATH environment variable. To find out where the
223 configuration has installed the manpages, type:
227 If the directories have a common stem, such as F</usr/local/man/man1>
228 and F</usr/local/man/man3>, you need only to add that stem
229 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
230 environment variable. If they do not share a stem, you'll have to add
233 If that doesn't work for some reason, you can still use the
234 supplied F<perldoc> script to view module information. You might
235 also look into getting a replacement man program.
237 If something strange has gone wrong with your program and you're not
238 sure where you should look for help, try the B<-w> switch first. It
239 will often point out exactly where the trouble is.
243 Perl is a language optimized for scanning arbitrary
244 text files, extracting information from those text files, and printing
245 reports based on that information. It's also a good language for many
246 system management tasks. The language is intended to be practical
247 (easy to use, efficient, complete) rather than beautiful (tiny,
250 Perl combines (in the author's opinion, anyway) some of the best
251 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
252 those languages should have little difficulty with it. (Language
253 historians will also note some vestiges of B<csh>, Pascal, and even
254 BASIC-PLUS.) Expression syntax corresponds closely to C
255 expression syntax. Unlike most Unix utilities, Perl does not
256 arbitrarily limit the size of your data--if you've got the memory,
257 Perl can slurp in your whole file as a single string. Recursion is of
258 unlimited depth. And the tables used by hashes (sometimes called
259 "associative arrays") grow as necessary to prevent degraded
260 performance. Perl can use sophisticated pattern matching techniques to
261 scan large amounts of data quickly. Although optimized for
262 scanning text, Perl can also deal with binary data, and can make dbm
263 files look like hashes. Setuid Perl scripts are safer than C programs
264 through a dataflow tracing mechanism that prevents many stupid
267 If you have a problem that would ordinarily use B<sed> or B<awk> or
268 B<sh>, but it exceeds their capabilities or must run a little faster,
269 and you don't want to write the silly thing in C, then Perl may be for
270 you. There are also translators to turn your B<sed> and B<awk>
271 scripts into Perl scripts.
273 But wait, there's more...
275 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
276 rewrite that provides the following additional benefits:
282 modularity and reusability using innumerable modules
284 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
288 embeddable and extensible
290 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
291 L<perlguts>, and L<xsubpp>.
295 roll-your-own magic variables (including multiple simultaneous DBM
298 Described in L<perltie> and L<AnyDBM_File>.
302 subroutines can now be overridden, autoloaded, and prototyped
304 Described in L<perlsub>.
308 arbitrarily nested data structures and anonymous functions
310 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
314 object-oriented programming
316 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
321 support for light-weight processes (threads)
323 Described in L<perlthrtut> and L<threads>.
327 support for Unicode, internationalization, and localization
329 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
335 Described in L<perlsub>.
339 regular expression enhancements
341 Described in L<perlre>, with additional examples in L<perlop>.
345 enhanced debugger and interactive Perl environment,
346 with integrated editor support
348 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
352 POSIX 1003.1 compliant library
354 Described in L<POSIX>.
358 Okay, that's I<definitely> enough hype.
362 Perl is available for most operating systems, including virtually
363 all Unix-like platforms. See L<perlport/"Supported Platforms">
372 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
374 If your Perl success stories and testimonials may be of help to others
375 who wish to advocate the use of Perl in their applications,
376 or if you wish to simply express your gratitude to Larry and the
377 Perl developers, please write to perl-thanks@perl.org .
381 "@INC" locations of perl libraries
385 a2p awk to perl translator
386 s2p sed to perl translator
388 http://www.perl.org/ the Perl homepage
389 http://www.perl.com/ Perl articles (O'Reilly)
390 http://www.cpan.org/ the Comprehensive Perl Archive
391 http://www.pm.org/ the Perl Mongers
395 The C<use warnings> pragma (and the B<-w> switch) produces some
398 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
399 diagnostics> pragma automatically turns Perl's normally terse warnings
400 and errors into these longer forms.
402 Compilation errors will tell you the line number of the error, with an
403 indication of the next token or token type that was to be examined.
404 (In a script passed to Perl via B<-e> switches, each
405 B<-e> is counted as one line.)
407 Setuid scripts have additional constraints that can produce error
408 messages such as "Insecure dependency". See L<perlsec>.
410 Did we mention that you should definitely consider using the B<-w>
415 The B<-w> switch is not mandatory.
417 Perl is at the mercy of your machine's definitions of various
418 operations such as type casting, atof(), and floating-point
419 output with sprintf().
421 If your stdio requires a seek or eof between reads and writes on a
422 particular stream, so does Perl. (This doesn't apply to sysread()
425 While none of the built-in data types have any arbitrary size limits
426 (apart from memory size), there are still a few arbitrary limits: a
427 given variable name may not be longer than 251 characters. Line numbers
428 displayed by diagnostics are internally stored as short integers,
429 so they are limited to a maximum of 65535 (higher numbers usually being
430 affected by wraparound).
432 You may mail your bug reports (be sure to include full configuration
433 information as output by the myconfig program in the perl source
434 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
435 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
436 can be used to help mail in a bug report.
438 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
439 don't tell anyone I said that.
443 The Perl motto is "There's more than one way to do it." Divining
444 how many more is left as an exercise to the reader.
446 The three principal virtues of a programmer are Laziness,
447 Impatience, and Hubris. See the Camel Book for why.