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