Remove the other 4 bits of MAD code designed to abort on local $^L.
[p5sagit/p5-mst-13.2.git] / pod / perl.pod
CommitLineData
a0d0e21e 1=head1 NAME
2
3perl - Practical Extraction and Report Language
4
5=head1 SYNOPSIS
6
df451b2a 7B<perl> S<[ B<-sTtuUWX> ]>
8 S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
9 S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
10 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ 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...'> ] [ B<-f> ]>
12 S<[ B<-A>[I<module>][=I<assertions>] ]>
13 S<[ B<-C [I<number/list>] >]>
14 S<[ B<-P> ]>
15 S<[ B<-S> ]>
16 S<[ B<-x>[I<dir>] ]>
17 S<[ B<-i>[I<extension>] ]>
18 S<[ B<-e> I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
c07a80fd 19
10151d09 20If you're new to Perl, you should start with L<perlintro>, which is a
21general intro for beginners and provides some background to help you
22navigate the rest of Perl's extensive documentation.
23
24For ease of access, the Perl manual has been split up into several sections.
a0d0e21e 25
fd7b6849 26=head2 Overview
27
fb9cefb4 28 perl Perl overview (this section)
10151d09 29 perlintro Perl introduction for beginners
fb9cefb4 30 perltoc Perl documentation table of contents
760ac839 31
fd7b6849 32=head2 Tutorials
33
7a2320f0 34 perlreftut Perl references short introduction
35 perldsc Perl data structures intro
36 perllol Perl data structures: arrays of arrays
7a2320f0 37
41630250 38 perlrequick Perl regular expressions quick start
7a2320f0 39 perlretut Perl regular expressions tutorial
40
41 perlboot Perl OO tutorial for beginners
42 perltoot Perl OO tutorial, part 1
43 perltooc Perl OO tutorial, part 2
44 perlbot Perl OO tricks and examples
45
46 perlstyle Perl style guide
47
41630250 48 perlcheat Perl cheat sheet
7a2320f0 49 perltrap Perl traps for the unwary
50 perldebtut Perl debugging tutorial
51
fd7b6849 52 perlfaq Perl frequently asked questions
53 perlfaq1 General Questions About Perl
54 perlfaq2 Obtaining and Learning about Perl
55 perlfaq3 Programming Tools
56 perlfaq4 Data Manipulation
57 perlfaq5 Files and Formats
58 perlfaq6 Regexes
59 perlfaq7 Perl Language Issues
60 perlfaq8 System Interaction
61 perlfaq9 Networking
0f542199 62
fd7b6849 63=head2 Reference Manual
413510b3 64
fb9cefb4 65 perlsyn Perl syntax
4755096e 66 perldata Perl data structures
fb9cefb4 67 perlop Perl operators and precedence
c2e66d9e 68 perlsub Perl subroutines
fd7b6849 69 perlfunc Perl built-in functions
413510b3 70 perlopentut Perl open() tutorial
41630250 71 perlpacktut Perl pack() and unpack() tutorial
c2e66d9e 72 perlpod Perl plain old documentation
41630250 73 perlpodspec Perl plain old documentation format specification
c2e66d9e 74 perlrun Perl execution and options
75 perldiag Perl diagnostic messages
41630250 76 perllexwarn Perl warnings and their control
4755096e 77 perldebug Perl debugging
fb9cefb4 78 perlvar Perl predefined variables
4755096e 79 perlre Perl regular expressions, the rest of the story
30487ceb 80 perlreref Perl regular expressions quick reference
d396a558 81 perlref Perl references, the rest of the story
fb9cefb4 82 perlform Perl formats
d396a558 83 perlobj Perl objects
d396a558 84 perltie Perl objects hidden behind simple variables
fd7b6849 85 perldbmfilter Perl DBM filters
760ac839 86
c2e66d9e 87 perlipc Perl interprocess communication
88 perlfork Perl fork() information
89 perlnumber Perl number semantics
53d7eaa8 90
c2e66d9e 91 perlthrtut Perl threads tutorial
41630250 92 perlothrtut Old Perl threads tutorial
c2e66d9e 93
94 perlport Perl portability guide
d396a558 95 perllocale Perl locale support
07fcf8ff 96 perluniintro Perl Unicode introduction
41630250 97 perlunicode Perl Unicode support
3426ea3d 98 perlunifaq Perl Unicode FAQ
aadaa455 99 perlunitut Perl Unicode tutorial
d396a558 100 perlebcdic Considerations for running Perl on EBCDIC platforms
c2e66d9e 101
d396a558 102 perlsec Perl security
4755096e 103
c2e66d9e 104 perlmod Perl modules: how they work
35bf961c 105 perlmodlib Perl modules: how to write and use
106 perlmodstyle Perl modules: how to write modules with style
fd7b6849 107 perlmodinstall Perl modules: how to install from CPAN
c2e66d9e 108 perlnewmod Perl modules: preparing a new module for distribution
a550ee30 109 perlpragma Perl modules: writing a user pragma
760ac839 110
fd7b6849 111 perlutil utilities packaged with the Perl distribution
760ac839 112
41630250 113 perlcompile Perl compiler suite intro
760ac839 114
fd7b6849 115 perlfilter Perl source filters
116
97a1d740 117 perlglossary Perl Glossary
118
fd7b6849 119=head2 Internals and C Language Interface
120
fb9cefb4 121 perlembed Perl ways to embed perl in your C or C++ application
41630250 122 perldebguts Perl debugging guts and tips
fb9cefb4 123 perlxstut Perl XS tutorial
4755096e 124 perlxs Perl XS application programming interface
f40a6c71 125 perlclib Internal replacements for standard C library functions
fb9cefb4 126 perlguts Perl internal functions for those doing extensions
127 perlcall Perl calling conventions from C
b23a565d 128 perlreguts Perl regular expression engine internals
fd7b6849 129
954c1994 130 perlapi Perl API listing (autogenerated)
131 perlintern Perl internal functions (autogenerated)
dc5c060f 132 perliol C API for Perl's implementation of IO in Layers
4755096e 133 perlapio Perl internal IO abstraction interface
fd7b6849 134
e8cd7eae 135 perlhack Perl hackers guide
4755096e 136
fd7b6849 137=head2 Miscellaneous
138
139 perlbook Perl book information
fd7b6849 140 perltodo Perl things to do
141
2a551100 142 perldoc Look up Perl documentation in Pod format
143
fb9cefb4 144 perlhist Perl history records
4755096e 145 perldelta Perl changes since previous version
f6eae373 146 perl594delta Perl changes in version 5.9.4
6c7deadb 147 perl593delta Perl changes in version 5.9.3
496c75d0 148 perl592delta Perl changes in version 5.9.2
e0eb806d 149 perl591delta Perl changes in version 5.9.1
1400179b 150 perl590delta Perl changes in version 5.9.0
c11a53c6 151 perl588delta Perl changes in version 5.8.8
315ba985 152 perl587delta Perl changes in version 5.8.7
e4bb216d 153 perl586delta Perl changes in version 5.8.6
07e9b5fe 154 perl585delta Perl changes in version 5.8.5
5f15c94e 155 perl584delta Perl changes in version 5.8.4
2e038148 156 perl583delta Perl changes in version 5.8.3
157 perl582delta Perl changes in version 5.8.2
b6235c4f 158 perl581delta Perl changes in version 5.8.1
2e038148 159 perl58delta Perl changes in version 5.8.0
77b096b5 160 perl573delta Perl changes in version 5.7.3
245d750e 161 perl572delta Perl changes in version 5.7.2
1db9e106 162 perl571delta Perl changes in version 5.7.1
163 perl570delta Perl changes in version 5.7.0
493a87da 164 perl561delta Perl changes in version 5.6.1
41630250 165 perl56delta Perl changes in version 5.6
4755096e 166 perl5005delta Perl changes in version 5.005
167 perl5004delta Perl changes in version 5.004
d516a115 168
2a551100 169 perlartistic Perl Artistic License
170 perlgpl GNU General Public License
171
d8416318 172=head2 Language-Specific
173
174 perlcn Perl for Simplified Chinese (in EUC-CN)
175 perljp Perl for Japanese (in EUC-JP)
176 perlko Perl for Korean (in EUC-KR)
177 perltw Perl for Traditional Chinese (in Big5)
178
fd7b6849 179=head2 Platform-Specific
180
37d4d706 181 perlaix Perl notes for AIX
a83b6f46 182 perlamiga Perl notes for AmigaOS
183 perlapollo Perl notes for Apollo DomainOS
184 perlbeos Perl notes for BeOS
dc5c060f 185 perlbs2000 Perl notes for POSIX-BC BS2000
a1f19229 186 perlce Perl notes for WinCE
49877630 187 perlcygwin Perl notes for Cygwin
245d750e 188 perldgux Perl notes for DG/UX
49877630 189 perldos Perl notes for DOS
9a997319 190 perlepoc Perl notes for EPOC
41630250 191 perlfreebsd Perl notes for FreeBSD
49877630 192 perlhpux Perl notes for HP-UX
a83b6f46 193 perlhurd Perl notes for Hurd
469e7be4 194 perlirix Perl notes for Irix
991e8403 195 perllinux Perl notes for Linux
41630250 196 perlmachten Perl notes for Power MachTen
26d9b02f 197 perlmacos Perl notes for Mac OS (Classic)
0d53b15f 198 perlmacosx Perl notes for Mac OS X
a83b6f46 199 perlmint Perl notes for MiNT
ab648d5e 200 perlmpeix Perl notes for MPE/iX
41630250 201 perlnetware Perl notes for NetWare
b0846812 202 perlopenbsd Perl notes for OpenBSD
49877630 203 perlos2 Perl notes for OS/2
204 perlos390 Perl notes for OS/390
522b859a 205 perlos400 Perl notes for OS/400
a83b6f46 206 perlplan9 Perl notes for Plan 9
207 perlqnx Perl notes for QNX
2f08ed66 208 perlriscos Perl notes for RISC OS
d420ca49 209 perlsolaris Perl notes for Solaris
27da23d5 210 perlsymbian Perl notes for Symbian
772ff3b9 211 perltru64 Perl notes for Tru64
41630250 212 perluts Perl notes for UTS
cbe1151c 213 perlvmesa Perl notes for VM/ESA
49877630 214 perlvms Perl notes for VMS
9a997319 215 perlvos Perl notes for Stratus VOS
49877630 216 perlwin32 Perl notes for Windows
217
a0d0e21e 218
19799a22 219By default, the manpages listed above are installed in the
fc952dec 220F</usr/local/man/> directory.
221
222Extensive additional documentation for Perl modules is available. The
223default configuration for perl will place this additional documentation
224in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
225subdirectory of the Perl library directory). Some of this additional
226documentation is distributed standard with Perl, but you'll also find
227documentation for third-party modules there.
228
229You should be able to view Perl's documentation with your man(1)
230program by including the proper directories in the appropriate start-up
231files, or in the MANPATH environment variable. To find out where the
232configuration has installed the manpages, type:
16d20bd9 233
760ac839 234 perl -V:man.dir
16d20bd9 235
fc952dec 236If the directories have a common stem, such as F</usr/local/man/man1>
237and F</usr/local/man/man3>, you need only to add that stem
238(F</usr/local/man>) to your man(1) configuration files or your MANPATH
239environment variable. If they do not share a stem, you'll have to add
240both stems.
16d20bd9 241
242If that doesn't work for some reason, you can still use the
4633a7c4 243supplied F<perldoc> script to view module information. You might
244also look into getting a replacement man program.
16d20bd9 245
a0d0e21e 246If something strange has gone wrong with your program and you're not
247sure where you should look for help, try the B<-w> switch first. It
248will often point out exactly where the trouble is.
249
250=head1 DESCRIPTION
251
5f05dabc 252Perl is a language optimized for scanning arbitrary
a0d0e21e 253text files, extracting information from those text files, and printing
254reports based on that information. It's also a good language for many
255system management tasks. The language is intended to be practical
256(easy to use, efficient, complete) rather than beautiful (tiny,
94d58c47 257elegant, minimal).
258
aa689395 259Perl combines (in the author's opinion, anyway) some of the best
260features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
261those languages should have little difficulty with it. (Language
262historians will also note some vestiges of B<csh>, Pascal, and even
14218588 263BASIC-PLUS.) Expression syntax corresponds closely to C
a0d0e21e 264expression syntax. Unlike most Unix utilities, Perl does not
265arbitrarily limit the size of your data--if you've got the memory,
aa689395 266Perl can slurp in your whole file as a single string. Recursion is of
0f31cffe 267unlimited depth. And the tables used by hashes (sometimes called
aa689395 268"associative arrays") grow as necessary to prevent degraded
0f31cffe 269performance. Perl can use sophisticated pattern matching techniques to
14218588 270scan large amounts of data quickly. Although optimized for
aa689395 271scanning text, Perl can also deal with binary data, and can make dbm
272files look like hashes. Setuid Perl scripts are safer than C programs
14218588 273through a dataflow tracing mechanism that prevents many stupid
aa689395 274security holes.
275
276If you have a problem that would ordinarily use B<sed> or B<awk> or
277B<sh>, but it exceeds their capabilities or must run a little faster,
278and you don't want to write the silly thing in C, then Perl may be for
279you. There are also translators to turn your B<sed> and B<awk>
280scripts into Perl scripts.
a0d0e21e 281
282But wait, there's more...
283
19799a22 284Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
285rewrite that provides the following additional benefits:
a0d0e21e 286
13a2d996 287=over 4
a0d0e21e 288
551e1d92 289=item *
290
291modularity and reusability using innumerable modules
a0d0e21e 292
19799a22 293Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
a0d0e21e 294
551e1d92 295=item *
296
297embeddable and extensible
a0d0e21e 298
19799a22 299Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
300L<perlguts>, and L<xsubpp>.
a0d0e21e 301
551e1d92 302=item *
303
63de3cb2 304roll-your-own magic variables (including multiple simultaneous DBM
305implementations)
a0d0e21e 306
19799a22 307Described in L<perltie> and L<AnyDBM_File>.
a0d0e21e 308
551e1d92 309=item *
310
311subroutines can now be overridden, autoloaded, and prototyped
a0d0e21e 312
19799a22 313Described in L<perlsub>.
a0d0e21e 314
551e1d92 315=item *
316
317arbitrarily nested data structures and anonymous functions
a0d0e21e 318
19799a22 319Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
a0d0e21e 320
551e1d92 321=item *
322
323object-oriented programming
a0d0e21e 324
f6b3c421 325Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
326and L<perlbot>.
a0d0e21e 327
551e1d92 328=item *
329
551e1d92 330support for light-weight processes (threads)
a0d0e21e 331
63de3cb2 332Described in L<perlthrtut> and L<threads>.
a0d0e21e 333
551e1d92 334=item *
335
63de3cb2 336support for Unicode, internationalization, and localization
a0d0e21e 337
63de3cb2 338Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
a0d0e21e 339
551e1d92 340=item *
341
342lexical scoping
a0d0e21e 343
19799a22 344Described in L<perlsub>.
a0d0e21e 345
551e1d92 346=item *
347
348regular expression enhancements
a0d0e21e 349
19799a22 350Described in L<perlre>, with additional examples in L<perlop>.
a0d0e21e 351
551e1d92 352=item *
353
354enhanced debugger and interactive Perl environment,
355with integrated editor support
a0d0e21e 356
f6b3c421 357Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
a0d0e21e 358
551e1d92 359=item *
360
361POSIX 1003.1 compliant library
5f05dabc 362
19799a22 363Described in L<POSIX>.
5f05dabc 364
a0d0e21e 365=back
366
68dc0745 367Okay, that's I<definitely> enough hype.
a0d0e21e 368
8e465e4e 369=head1 AVAILABILITY
370
14218588 371Perl is available for most operating systems, including virtually
055fd3a9 372all Unix-like platforms. See L<perlport/"Supported Platforms">
373for a listing.
8bc4a6bb 374
a0d0e21e 375=head1 ENVIRONMENT
376
1e422769 377See L<perlrun>.
a0d0e21e 378
379=head1 AUTHOR
380
19799a22 381Larry Wall <larry@wall.org>, with the help of oodles of other folks.
a0d0e21e 382
a99b1639 383If your Perl success stories and testimonials may be of help to others
384who wish to advocate the use of Perl in their applications,
385or if you wish to simply express your gratitude to Larry and the
19799a22 386Perl developers, please write to perl-thanks@perl.org .
a99b1639 387
a0d0e21e 388=head1 FILES
389
5f05dabc 390 "@INC" locations of perl libraries
a0d0e21e 391
392=head1 SEE ALSO
393
394 a2p awk to perl translator
395 s2p sed to perl translator
396
c5f69108 397 http://www.perl.org/ the Perl homepage
da9e6348 398 http://www.perl.com/ Perl articles (O'Reilly)
f6b3c421 399 http://www.cpan.org/ the Comprehensive Perl Archive
c5f69108 400 http://www.pm.org/ the Perl Mongers
19799a22 401
a0d0e21e 402=head1 DIAGNOSTICS
403
9f1b1f2d 404The C<use warnings> pragma (and the B<-w> switch) produces some
405lovely diagnostics.
a0d0e21e 406
5a964f20 407See L<perldiag> for explanations of all Perl's diagnostics. The C<use
408diagnostics> pragma automatically turns Perl's normally terse warnings
409and errors into these longer forms.
a0d0e21e 410
411Compilation errors will tell you the line number of the error, with an
412indication of the next token or token type that was to be examined.
14218588 413(In a script passed to Perl via B<-e> switches, each
a0d0e21e 414B<-e> is counted as one line.)
415
416Setuid scripts have additional constraints that can produce error
417messages such as "Insecure dependency". See L<perlsec>.
418
419Did we mention that you should definitely consider using the B<-w>
420switch?
421
422=head1 BUGS
423
424The B<-w> switch is not mandatory.
425
426Perl is at the mercy of your machine's definitions of various
1b3f7d21 427operations such as type casting, atof(), and floating-point
428output with sprintf().
a0d0e21e 429
748a9306 430If your stdio requires a seek or eof between reads and writes on a
a0d0e21e 431particular stream, so does Perl. (This doesn't apply to sysread()
432and syswrite().)
433
434While none of the built-in data types have any arbitrary size limits
435(apart from memory size), there are still a few arbitrary limits: a
a30ac152 436given variable name may not be longer than 251 characters. Line numbers
437displayed by diagnostics are internally stored as short integers,
438so they are limited to a maximum of 65535 (higher numbers usually being
439affected by wraparound).
a0d0e21e 440
b0607b7a 441You may mail your bug reports (be sure to include full configuration
19799a22 442information as output by the myconfig program in the perl source
7f2de2d2 443tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
055fd3a9 444in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
19799a22 445can be used to help mail in a bug report.
4633a7c4 446
a0d0e21e 447Perl actually stands for Pathologically Eclectic Rubbish Lister, but
448don't tell anyone I said that.
449
450=head1 NOTES
451
452The Perl motto is "There's more than one way to do it." Divining
453how many more is left as an exercise to the reader.
454
4633a7c4 455The three principal virtues of a programmer are Laziness,
a0d0e21e 456Impatience, and Hubris. See the Camel Book for why.
16d20bd9 457