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