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 perl572delta Perl changes in version 5.7.2
132 perl571delta Perl changes in version 5.7.1
133 perl570delta Perl changes in version 5.7.0
134 perl561delta Perl changes in version 5.6.1
135 perl56delta Perl changes in version 5.6
136 perl5005delta Perl changes in version 5.005
137 perl5004delta Perl changes in version 5.004
139 =head2 Language-Specific
141 perlcn Perl for Simplified Chinese (in EUC-CN)
142 perljp Perl for Japanese (in EUC-JP)
143 perlko Perl for Korean (in EUC-KR)
144 perltw Perl for Traditional Chinese (in Big5)
146 =head2 Platform-Specific
148 perlaix Perl notes for AIX
149 perlamiga Perl notes for AmigaOS
150 perlapollo Perl notes for Apollo DomainOS
151 perlbeos Perl notes for BeOS
152 perlbs2000 Perl notes for POSIX-BC BS2000
153 perlce Perl notes for WinCE
154 perlcygwin Perl notes for Cygwin
155 perldgux Perl notes for DG/UX
156 perldos Perl notes for DOS
157 perlepoc Perl notes for EPOC
158 perlfreebsd Perl notes for FreeBSD
159 perlhpux Perl notes for HP-UX
160 perlhurd Perl notes for Hurd
161 perlirix Perl notes for Irix
162 perlmachten Perl notes for Power MachTen
163 perlmacos Perl notes for Mac OS (Classic)
164 perlmint Perl notes for MiNT
165 perlmpeix Perl notes for MPE/iX
166 perlnetware Perl notes for NetWare
167 perlos2 Perl notes for OS/2
168 perlos390 Perl notes for OS/390
169 perlplan9 Perl notes for Plan 9
170 perlqnx Perl notes for QNX
171 perlsolaris Perl notes for Solaris
172 perltru64 Perl notes for Tru64
173 perluts Perl notes for UTS
174 perlvmesa Perl notes for VM/ESA
175 perlvms Perl notes for VMS
176 perlvos Perl notes for Stratus VOS
177 perlwin32 Perl notes for Windows
180 By default, the manpages listed above are installed in the
181 F</usr/local/man/> directory.
183 Extensive additional documentation for Perl modules is available. The
184 default configuration for perl will place this additional documentation
185 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
186 subdirectory of the Perl library directory). Some of this additional
187 documentation is distributed standard with Perl, but you'll also find
188 documentation for third-party modules there.
190 You should be able to view Perl's documentation with your man(1)
191 program by including the proper directories in the appropriate start-up
192 files, or in the MANPATH environment variable. To find out where the
193 configuration has installed the manpages, type:
197 If the directories have a common stem, such as F</usr/local/man/man1>
198 and F</usr/local/man/man3>, you need only to add that stem
199 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
200 environment variable. If they do not share a stem, you'll have to add
203 If that doesn't work for some reason, you can still use the
204 supplied F<perldoc> script to view module information. You might
205 also look into getting a replacement man program.
207 If something strange has gone wrong with your program and you're not
208 sure where you should look for help, try the B<-w> switch first. It
209 will often point out exactly where the trouble is.
213 Perl is a language optimized for scanning arbitrary
214 text files, extracting information from those text files, and printing
215 reports based on that information. It's also a good language for many
216 system management tasks. The language is intended to be practical
217 (easy to use, efficient, complete) rather than beautiful (tiny,
220 Perl combines (in the author's opinion, anyway) some of the best
221 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
222 those languages should have little difficulty with it. (Language
223 historians will also note some vestiges of B<csh>, Pascal, and even
224 BASIC-PLUS.) Expression syntax corresponds closely to C
225 expression syntax. Unlike most Unix utilities, Perl does not
226 arbitrarily limit the size of your data--if you've got the memory,
227 Perl can slurp in your whole file as a single string. Recursion is of
228 unlimited depth. And the tables used by hashes (sometimes called
229 "associative arrays") grow as necessary to prevent degraded
230 performance. Perl can use sophisticated pattern matching techniques to
231 scan large amounts of data quickly. Although optimized for
232 scanning text, Perl can also deal with binary data, and can make dbm
233 files look like hashes. Setuid Perl scripts are safer than C programs
234 through a dataflow tracing mechanism that prevents many stupid
237 If you have a problem that would ordinarily use B<sed> or B<awk> or
238 B<sh>, but it exceeds their capabilities or must run a little faster,
239 and you don't want to write the silly thing in C, then Perl may be for
240 you. There are also translators to turn your B<sed> and B<awk>
241 scripts into Perl scripts.
243 But wait, there's more...
245 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
246 rewrite that provides the following additional benefits:
252 modularity and reusability using innumerable modules
254 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
258 embeddable and extensible
260 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
261 L<perlguts>, and L<xsubpp>.
265 roll-your-own magic variables (including multiple simultaneous DBM implementations)
267 Described in L<perltie> and L<AnyDBM_File>.
271 subroutines can now be overridden, autoloaded, and prototyped
273 Described in L<perlsub>.
277 arbitrarily nested data structures and anonymous functions
279 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
283 object-oriented programming
285 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
290 compilability into C code or Perl bytecode
292 Described in L<B> and L<B::Bytecode>.
296 support for light-weight processes (threads)
298 Described in L<perlthrtut> and L<Thread>.
302 support for internationalization, localization, and Unicode
304 Described in L<perllocale> and L<utf8>.
310 Described in L<perlsub>.
314 regular expression enhancements
316 Described in L<perlre>, with additional examples in L<perlop>.
320 enhanced debugger and interactive Perl environment,
321 with integrated editor support
323 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
327 POSIX 1003.1 compliant library
329 Described in L<POSIX>.
333 Okay, that's I<definitely> enough hype.
337 Perl is available for most operating systems, including virtually
338 all Unix-like platforms. See L<perlport/"Supported Platforms">
347 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
349 If your Perl success stories and testimonials may be of help to others
350 who wish to advocate the use of Perl in their applications,
351 or if you wish to simply express your gratitude to Larry and the
352 Perl developers, please write to perl-thanks@perl.org .
356 "@INC" locations of perl libraries
360 a2p awk to perl translator
361 s2p sed to perl translator
363 http://www.perl.com/ the Perl Home Page
364 http://www.cpan.org/ the Comprehensive Perl Archive
365 http://www.perl.org/ Perl Mongers (Perl user groups)
369 The C<use warnings> pragma (and the B<-w> switch) produces some
372 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
373 diagnostics> pragma automatically turns Perl's normally terse warnings
374 and errors into these longer forms.
376 Compilation errors will tell you the line number of the error, with an
377 indication of the next token or token type that was to be examined.
378 (In a script passed to Perl via B<-e> switches, each
379 B<-e> is counted as one line.)
381 Setuid scripts have additional constraints that can produce error
382 messages such as "Insecure dependency". See L<perlsec>.
384 Did we mention that you should definitely consider using the B<-w>
389 The B<-w> switch is not mandatory.
391 Perl is at the mercy of your machine's definitions of various
392 operations such as type casting, atof(), and floating-point
393 output with sprintf().
395 If your stdio requires a seek or eof between reads and writes on a
396 particular stream, so does Perl. (This doesn't apply to sysread()
399 While none of the built-in data types have any arbitrary size limits
400 (apart from memory size), there are still a few arbitrary limits: a
401 given variable name may not be longer than 251 characters. Line numbers
402 displayed by diagnostics are internally stored as short integers,
403 so they are limited to a maximum of 65535 (higher numbers usually being
404 affected by wraparound).
406 You may mail your bug reports (be sure to include full configuration
407 information as output by the myconfig program in the perl source
408 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
409 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
410 can be used to help mail in a bug report.
412 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
413 don't tell anyone I said that.
417 The Perl motto is "There's more than one way to do it." Divining
418 how many more is left as an exercise to the reader.
420 The three principal virtues of a programmer are Laziness,
421 Impatience, and Hubris. See the Camel Book for why.