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