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 perlpacktut Perl pack() and unpack() tutorial
66 perlpod Perl plain old documentation
67 perlpodspec Perl plain old documentation format specification
68 perlrun Perl execution and options
69 perldiag Perl diagnostic messages
70 perllexwarn Perl warnings and their control
71 perldebug Perl debugging
72 perlvar Perl predefined variables
73 perlre Perl regular expressions, the rest of the story
74 perlref Perl references, the rest of the story
77 perltie Perl objects hidden behind simple variables
78 perldbmfilter Perl DBM filters
80 perlipc Perl interprocess communication
81 perlfork Perl fork() information
82 perlnumber Perl number semantics
84 perlthrtut Perl threads tutorial
85 perlothrtut Old Perl threads tutorial
87 perlport Perl portability guide
88 perllocale Perl locale support
89 perluniintro Perl Unicode introduction
90 perlunicode Perl Unicode support
91 perlebcdic Considerations for running Perl on EBCDIC platforms
95 perlmod Perl modules: how they work
96 perlmodlib Perl modules: how to write and use
97 perlmodstyle Perl modules: how to write modules with style
98 perlmodinstall Perl modules: how to install from CPAN
99 perlnewmod Perl modules: preparing a new module for distribution
101 perlutil utilities packaged with the Perl distribution
103 perlcompile Perl compiler suite intro
105 perlfilter Perl source filters
107 =head2 Internals and C Language Interface
109 perlembed Perl ways to embed perl in your C or C++ application
110 perldebguts Perl debugging guts and tips
111 perlxstut Perl XS tutorial
112 perlxs Perl XS application programming interface
113 perlclib Internal replacements for standard C library functions
114 perlguts Perl internal functions for those doing extensions
115 perlcall Perl calling conventions from C
117 perlapi Perl API listing (autogenerated)
118 perlintern Perl internal functions (autogenerated)
119 perliol C API for Perl's implementation of IO in Layers
120 perlapio Perl internal IO abstraction interface
122 perlhack Perl hackers guide
126 perlbook Perl book information
127 perltodo Perl things to do
129 perlhist Perl history records
130 perldelta Perl changes since previous version
131 perl573delta Perl changes in version 5.7.3
132 perl572delta Perl changes in version 5.7.2
133 perl571delta Perl changes in version 5.7.1
134 perl570delta Perl changes in version 5.7.0
135 perl561delta Perl changes in version 5.6.1
136 perl56delta Perl changes in version 5.6
137 perl5005delta Perl changes in version 5.005
138 perl5004delta Perl changes in version 5.004
140 =head2 Language-Specific
142 perlcn Perl for Simplified Chinese (in EUC-CN)
143 perljp Perl for Japanese (in EUC-JP)
144 perlko Perl for Korean (in EUC-KR)
145 perltw Perl for Traditional Chinese (in Big5)
147 =head2 Platform-Specific
149 perlaix Perl notes for AIX
150 perlamiga Perl notes for AmigaOS
151 perlapollo Perl notes for Apollo DomainOS
152 perlbeos Perl notes for BeOS
153 perlbs2000 Perl notes for POSIX-BC BS2000
154 perlce Perl notes for WinCE
155 perlcygwin Perl notes for Cygwin
156 perldgux Perl notes for DG/UX
157 perldos Perl notes for DOS
158 perlepoc Perl notes for EPOC
159 perlfreebsd Perl notes for FreeBSD
160 perlhpux Perl notes for HP-UX
161 perlhurd Perl notes for Hurd
162 perlirix Perl notes for Irix
163 perlmachten Perl notes for Power MachTen
164 perlmacos Perl notes for Mac OS (Classic)
165 perlmint Perl notes for MiNT
166 perlmpeix Perl notes for MPE/iX
167 perlnetware Perl notes for NetWare
168 perlos2 Perl notes for OS/2
169 perlos390 Perl notes for OS/390
170 perlos400 Perl notes for OS/400
171 perlplan9 Perl notes for Plan 9
172 perlqnx Perl notes for QNX
173 perlsolaris Perl notes for Solaris
174 perltru64 Perl notes for Tru64
175 perluts Perl notes for UTS
176 perlvmesa Perl notes for VM/ESA
177 perlvms Perl notes for VMS
178 perlvos Perl notes for Stratus VOS
179 perlwin32 Perl notes for Windows
182 By default, the manpages listed above are installed in the
183 F</usr/local/man/> directory.
185 Extensive additional documentation for Perl modules is available. The
186 default configuration for perl will place this additional documentation
187 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
188 subdirectory of the Perl library directory). Some of this additional
189 documentation is distributed standard with Perl, but you'll also find
190 documentation for third-party modules there.
192 You should be able to view Perl's documentation with your man(1)
193 program by including the proper directories in the appropriate start-up
194 files, or in the MANPATH environment variable. To find out where the
195 configuration has installed the manpages, type:
199 If the directories have a common stem, such as F</usr/local/man/man1>
200 and F</usr/local/man/man3>, you need only to add that stem
201 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
202 environment variable. If they do not share a stem, you'll have to add
205 If that doesn't work for some reason, you can still use the
206 supplied F<perldoc> script to view module information. You might
207 also look into getting a replacement man program.
209 If something strange has gone wrong with your program and you're not
210 sure where you should look for help, try the B<-w> switch first. It
211 will often point out exactly where the trouble is.
215 Perl is a language optimized for scanning arbitrary
216 text files, extracting information from those text files, and printing
217 reports based on that information. It's also a good language for many
218 system management tasks. The language is intended to be practical
219 (easy to use, efficient, complete) rather than beautiful (tiny,
222 Perl combines (in the author's opinion, anyway) some of the best
223 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
224 those languages should have little difficulty with it. (Language
225 historians will also note some vestiges of B<csh>, Pascal, and even
226 BASIC-PLUS.) Expression syntax corresponds closely to C
227 expression syntax. Unlike most Unix utilities, Perl does not
228 arbitrarily limit the size of your data--if you've got the memory,
229 Perl can slurp in your whole file as a single string. Recursion is of
230 unlimited depth. And the tables used by hashes (sometimes called
231 "associative arrays") grow as necessary to prevent degraded
232 performance. Perl can use sophisticated pattern matching techniques to
233 scan large amounts of data quickly. Although optimized for
234 scanning text, Perl can also deal with binary data, and can make dbm
235 files look like hashes. Setuid Perl scripts are safer than C programs
236 through a dataflow tracing mechanism that prevents many stupid
239 If you have a problem that would ordinarily use B<sed> or B<awk> or
240 B<sh>, but it exceeds their capabilities or must run a little faster,
241 and you don't want to write the silly thing in C, then Perl may be for
242 you. There are also translators to turn your B<sed> and B<awk>
243 scripts into Perl scripts.
245 But wait, there's more...
247 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
248 rewrite that provides the following additional benefits:
254 modularity and reusability using innumerable modules
256 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
260 embeddable and extensible
262 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
263 L<perlguts>, and L<xsubpp>.
267 roll-your-own magic variables (including multiple simultaneous DBM
270 Described in L<perltie> and L<AnyDBM_File>.
274 subroutines can now be overridden, autoloaded, and prototyped
276 Described in L<perlsub>.
280 arbitrarily nested data structures and anonymous functions
282 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
286 object-oriented programming
288 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
293 support for light-weight processes (threads)
295 Described in L<perlthrtut> and L<threads>.
299 support for Unicode, internationalization, and localization
301 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
307 Described in L<perlsub>.
311 regular expression enhancements
313 Described in L<perlre>, with additional examples in L<perlop>.
317 enhanced debugger and interactive Perl environment,
318 with integrated editor support
320 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
324 POSIX 1003.1 compliant library
326 Described in L<POSIX>.
330 Okay, that's I<definitely> enough hype.
334 Perl is available for most operating systems, including virtually
335 all Unix-like platforms. See L<perlport/"Supported Platforms">
344 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
346 If your Perl success stories and testimonials may be of help to others
347 who wish to advocate the use of Perl in their applications,
348 or if you wish to simply express your gratitude to Larry and the
349 Perl developers, please write to perl-thanks@perl.org .
353 "@INC" locations of perl libraries
357 a2p awk to perl translator
358 s2p sed to perl translator
360 http://www.perl.com/ the Perl Home Page
361 http://www.cpan.org/ the Comprehensive Perl Archive
362 http://www.perl.org/ Perl Mongers (Perl user groups)
366 The C<use warnings> pragma (and the B<-w> switch) produces some
369 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
370 diagnostics> pragma automatically turns Perl's normally terse warnings
371 and errors into these longer forms.
373 Compilation errors will tell you the line number of the error, with an
374 indication of the next token or token type that was to be examined.
375 (In a script passed to Perl via B<-e> switches, each
376 B<-e> is counted as one line.)
378 Setuid scripts have additional constraints that can produce error
379 messages such as "Insecure dependency". See L<perlsec>.
381 Did we mention that you should definitely consider using the B<-w>
386 The B<-w> switch is not mandatory.
388 Perl is at the mercy of your machine's definitions of various
389 operations such as type casting, atof(), and floating-point
390 output with sprintf().
392 If your stdio requires a seek or eof between reads and writes on a
393 particular stream, so does Perl. (This doesn't apply to sysread()
396 While none of the built-in data types have any arbitrary size limits
397 (apart from memory size), there are still a few arbitrary limits: a
398 given variable name may not be longer than 251 characters. Line numbers
399 displayed by diagnostics are internally stored as short integers,
400 so they are limited to a maximum of 65535 (higher numbers usually being
401 affected by wraparound).
403 You may mail your bug reports (be sure to include full configuration
404 information as output by the myconfig program in the perl source
405 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
406 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
407 can be used to help mail in a bug report.
409 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
410 don't tell anyone I said that.
414 The Perl motto is "There's more than one way to do it." Divining
415 how many more is left as an exercise to the reader.
417 The three principal virtues of a programmer are Laziness,
418 Impatience, and Hubris. See the Camel Book for why.