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 perl587delta Perl changes in version 5.8.7
141 perl586delta Perl changes in version 5.8.6
142 perl585delta Perl changes in version 5.8.5
143 perl584delta Perl changes in version 5.8.4
144 perl583delta Perl changes in version 5.8.3
145 perl582delta Perl changes in version 5.8.2
146 perl581delta Perl changes in version 5.8.1
147 perl58delta Perl changes in version 5.8.0
148 perl573delta Perl changes in version 5.7.3
149 perl572delta Perl changes in version 5.7.2
150 perl571delta Perl changes in version 5.7.1
151 perl570delta Perl changes in version 5.7.0
152 perl561delta Perl changes in version 5.6.1
153 perl56delta Perl changes in version 5.6
154 perl5005delta Perl changes in version 5.005
155 perl5004delta Perl changes in version 5.004
157 perlartistic Perl Artistic License
158 perlgpl GNU General Public License
160 =head2 Language-Specific
162 perlcn Perl for Simplified Chinese (in EUC-CN)
163 perljp Perl for Japanese (in EUC-JP)
164 perlko Perl for Korean (in EUC-KR)
165 perltw Perl for Traditional Chinese (in Big5)
167 =head2 Platform-Specific
169 perlaix Perl notes for AIX
170 perlamiga Perl notes for AmigaOS
171 perlapollo Perl notes for Apollo DomainOS
172 perlbeos Perl notes for BeOS
173 perlbs2000 Perl notes for POSIX-BC BS2000
174 perlce Perl notes for WinCE
175 perlcygwin Perl notes for Cygwin
176 perldgux Perl notes for DG/UX
177 perldos Perl notes for DOS
178 perlepoc Perl notes for EPOC
179 perlfreebsd Perl notes for FreeBSD
180 perlhpux Perl notes for HP-UX
181 perlhurd Perl notes for Hurd
182 perlirix Perl notes for Irix
183 perlmachten Perl notes for Power MachTen
184 perlmacos Perl notes for Mac OS (Classic)
185 perlmacosx Perl notes for Mac OS X
186 perlmint Perl notes for MiNT
187 perlmpeix Perl notes for MPE/iX
188 perlnetware Perl notes for NetWare
189 perlopenbsd Perl notes for OpenBSD
190 perlos2 Perl notes for OS/2
191 perlos390 Perl notes for OS/390
192 perlos400 Perl notes for OS/400
193 perlplan9 Perl notes for Plan 9
194 perlqnx Perl notes for QNX
195 perlsolaris Perl notes for Solaris
196 perlsymbian Perl notes for Symbian
197 perltru64 Perl notes for Tru64
198 perluts Perl notes for UTS
199 perlvmesa Perl notes for VM/ESA
200 perlvms Perl notes for VMS
201 perlvos Perl notes for Stratus VOS
202 perlwin32 Perl notes for Windows
205 By default, the manpages listed above are installed in the
206 F</usr/local/man/> directory.
208 Extensive additional documentation for Perl modules is available. The
209 default configuration for perl will place this additional documentation
210 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
211 subdirectory of the Perl library directory). Some of this additional
212 documentation is distributed standard with Perl, but you'll also find
213 documentation for third-party modules there.
215 You should be able to view Perl's documentation with your man(1)
216 program by including the proper directories in the appropriate start-up
217 files, or in the MANPATH environment variable. To find out where the
218 configuration has installed the manpages, type:
222 If the directories have a common stem, such as F</usr/local/man/man1>
223 and F</usr/local/man/man3>, you need only to add that stem
224 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
225 environment variable. If they do not share a stem, you'll have to add
228 If that doesn't work for some reason, you can still use the
229 supplied F<perldoc> script to view module information. You might
230 also look into getting a replacement man program.
232 If something strange has gone wrong with your program and you're not
233 sure where you should look for help, try the B<-w> switch first. It
234 will often point out exactly where the trouble is.
238 Perl is a language optimized for scanning arbitrary
239 text files, extracting information from those text files, and printing
240 reports based on that information. It's also a good language for many
241 system management tasks. The language is intended to be practical
242 (easy to use, efficient, complete) rather than beautiful (tiny,
245 Perl combines (in the author's opinion, anyway) some of the best
246 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
247 those languages should have little difficulty with it. (Language
248 historians will also note some vestiges of B<csh>, Pascal, and even
249 BASIC-PLUS.) Expression syntax corresponds closely to C
250 expression syntax. Unlike most Unix utilities, Perl does not
251 arbitrarily limit the size of your data--if you've got the memory,
252 Perl can slurp in your whole file as a single string. Recursion is of
253 unlimited depth. And the tables used by hashes (sometimes called
254 "associative arrays") grow as necessary to prevent degraded
255 performance. Perl can use sophisticated pattern matching techniques to
256 scan large amounts of data quickly. Although optimized for
257 scanning text, Perl can also deal with binary data, and can make dbm
258 files look like hashes. Setuid Perl scripts are safer than C programs
259 through a dataflow tracing mechanism that prevents many stupid
262 If you have a problem that would ordinarily use B<sed> or B<awk> or
263 B<sh>, but it exceeds their capabilities or must run a little faster,
264 and you don't want to write the silly thing in C, then Perl may be for
265 you. There are also translators to turn your B<sed> and B<awk>
266 scripts into Perl scripts.
268 But wait, there's more...
270 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
271 rewrite that provides the following additional benefits:
277 modularity and reusability using innumerable modules
279 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
283 embeddable and extensible
285 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
286 L<perlguts>, and L<xsubpp>.
290 roll-your-own magic variables (including multiple simultaneous DBM
293 Described in L<perltie> and L<AnyDBM_File>.
297 subroutines can now be overridden, autoloaded, and prototyped
299 Described in L<perlsub>.
303 arbitrarily nested data structures and anonymous functions
305 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
309 object-oriented programming
311 Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
316 support for light-weight processes (threads)
318 Described in L<perlthrtut> and L<threads>.
322 support for Unicode, internationalization, and localization
324 Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
330 Described in L<perlsub>.
334 regular expression enhancements
336 Described in L<perlre>, with additional examples in L<perlop>.
340 enhanced debugger and interactive Perl environment,
341 with integrated editor support
343 Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
347 POSIX 1003.1 compliant library
349 Described in L<POSIX>.
353 Okay, that's I<definitely> enough hype.
357 Perl is available for most operating systems, including virtually
358 all Unix-like platforms. See L<perlport/"Supported Platforms">
367 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
369 If your Perl success stories and testimonials may be of help to others
370 who wish to advocate the use of Perl in their applications,
371 or if you wish to simply express your gratitude to Larry and the
372 Perl developers, please write to perl-thanks@perl.org .
376 "@INC" locations of perl libraries
380 a2p awk to perl translator
381 s2p sed to perl translator
383 http://www.perl.org/ the Perl homepage
384 http://www.perl.com/ Perl articles (O'Reilly)
385 http://www.cpan.org/ the Comprehensive Perl Archive
386 http://www.pm.org/ the Perl Mongers
390 The C<use warnings> pragma (and the B<-w> switch) produces some
393 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
394 diagnostics> pragma automatically turns Perl's normally terse warnings
395 and errors into these longer forms.
397 Compilation errors will tell you the line number of the error, with an
398 indication of the next token or token type that was to be examined.
399 (In a script passed to Perl via B<-e> switches, each
400 B<-e> is counted as one line.)
402 Setuid scripts have additional constraints that can produce error
403 messages such as "Insecure dependency". See L<perlsec>.
405 Did we mention that you should definitely consider using the B<-w>
410 The B<-w> switch is not mandatory.
412 Perl is at the mercy of your machine's definitions of various
413 operations such as type casting, atof(), and floating-point
414 output with sprintf().
416 If your stdio requires a seek or eof between reads and writes on a
417 particular stream, so does Perl. (This doesn't apply to sysread()
420 While none of the built-in data types have any arbitrary size limits
421 (apart from memory size), there are still a few arbitrary limits: a
422 given variable name may not be longer than 251 characters. Line numbers
423 displayed by diagnostics are internally stored as short integers,
424 so they are limited to a maximum of 65535 (higher numbers usually being
425 affected by wraparound).
427 You may mail your bug reports (be sure to include full configuration
428 information as output by the myconfig program in the perl source
429 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
430 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
431 can be used to help mail in a bug report.
433 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
434 don't tell anyone I said that.
438 The Perl motto is "There's more than one way to do it." Divining
439 how many more is left as an exercise to the reader.
441 The three principal virtues of a programmer are Laziness,
442 Impatience, and Hubris. See the Camel Book for why.