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1 | =head1 NAME |
2 | ||
3 | perl - Practical Extraction and Report Language | |
4 | ||
5 | =head1 SYNOPSIS | |
6 | ||
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> ]...> | |
14 | ||
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. | |
18 | ||
19 | For ease of access, the Perl manual has been split up into several sections. | |
20 | ||
21 | =head2 Overview | |
22 | ||
23 | perl Perl overview (this section) | |
24 | perlintro Perl introduction for beginners | |
25 | perltoc Perl documentation table of contents | |
26 | ||
27 | =head2 Tutorials | |
28 | ||
29 | perlreftut Perl references short introduction | |
30 | perldsc Perl data structures intro | |
31 | perllol Perl data structures: arrays of arrays | |
32 | ||
33 | perlrequick Perl regular expressions quick start | |
34 | perlretut Perl regular expressions tutorial | |
35 | ||
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 | |
40 | ||
41 | perlstyle Perl style guide | |
42 | ||
43 | perltrap Perl traps for the unwary | |
44 | perldebtut Perl debugging tutorial | |
45 | ||
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 | |
52 | perlfaq6 Regexes | |
53 | perlfaq7 Perl Language Issues | |
54 | perlfaq8 System Interaction | |
55 | perlfaq9 Networking | |
56 | ||
57 | =head2 Reference Manual | |
58 | ||
59 | perlsyn Perl syntax | |
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 | |
75 | perlform Perl formats | |
76 | perlobj Perl objects | |
77 | perltie Perl objects hidden behind simple variables | |
78 | perldbmfilter Perl DBM filters | |
79 | ||
80 | perlipc Perl interprocess communication | |
81 | perlfork Perl fork() information | |
82 | perlnumber Perl number semantics | |
83 | ||
84 | perlthrtut Perl threads tutorial | |
85 | perlothrtut Old Perl threads tutorial | |
86 | ||
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 | |
92 | ||
93 | perlsec Perl security | |
94 | ||
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 | |
100 | ||
101 | perlutil utilities packaged with the Perl distribution | |
102 | ||
103 | perlcompile Perl compiler suite intro | |
104 | ||
105 | perlfilter Perl source filters | |
106 | ||
107 | =head2 Internals and C Language Interface | |
108 | ||
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 | |
116 | ||
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 | |
121 | ||
122 | perlhack Perl hackers guide | |
123 | ||
124 | =head2 Miscellaneous | |
125 | ||
126 | perlbook Perl book information | |
127 | perltodo Perl things to do | |
128 | ||
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 | perl561delta Perl changes in version 5.6.1 | |
135 | perl56delta Perl changes in version 5.6 | |
136 | perl5005delta Perl changes in version 5.005 | |
137 | perl5004delta Perl changes in version 5.004 | |
138 | ||
139 | =head2 Language-Specific | |
140 | ||
141 | perlcn Perl for Simplified Chinese (in EUC-CN) | |
142 | perljp Perl for Japanese (in EUC-JP) | |
143 | perlko Perl for Korean (in EUC-KR) | |
144 | perltw Perl for Traditional Chinese (in Big5) | |
145 | ||
146 | =head2 Platform-Specific | |
147 | ||
148 | perlaix Perl notes for AIX | |
149 | perlamiga Perl notes for AmigaOS | |
150 | perlapollo Perl notes for Apollo DomainOS | |
151 | perlbeos Perl notes for BeOS | |
152 | perlbs2000 Perl notes for POSIX-BC BS2000 | |
153 | perlce Perl notes for WinCE | |
154 | perlcygwin Perl notes for Cygwin | |
155 | perldgux Perl notes for DG/UX | |
156 | perldos Perl notes for DOS | |
157 | perlepoc Perl notes for EPOC | |
158 | perlfreebsd Perl notes for FreeBSD | |
159 | perlhpux Perl notes for HP-UX | |
160 | perlhurd Perl notes for Hurd | |
161 | perlirix Perl notes for Irix | |
162 | perlmachten Perl notes for Power MachTen | |
163 | perlmacos Perl notes for Mac OS (Classic) | |
164 | perlmint Perl notes for MiNT | |
165 | perlmpeix Perl notes for MPE/iX | |
166 | perlnetware Perl notes for NetWare | |
167 | perlos2 Perl notes for OS/2 | |
168 | perlos390 Perl notes for OS/390 | |
169 | perlplan9 Perl notes for Plan 9 | |
170 | perlqnx Perl notes for QNX | |
171 | perlsolaris Perl notes for Solaris | |
172 | perltru64 Perl notes for Tru64 | |
173 | perluts Perl notes for UTS | |
174 | perlvmesa Perl notes for VM/ESA | |
175 | perlvms Perl notes for VMS | |
176 | perlvos Perl notes for Stratus VOS | |
177 | perlwin32 Perl notes for Windows | |
178 | ||
179 | ||
180 | By default, the manpages listed above are installed in the | |
181 | F</usr/local/man/> directory. | |
182 | ||
183 | Extensive additional documentation for Perl modules is available. The | |
184 | default configuration for perl will place this additional documentation | |
185 | in the F</usr/local/lib/perl5/man> directory (or else in the F<man> | |
186 | subdirectory of the Perl library directory). Some of this additional | |
187 | documentation is distributed standard with Perl, but you'll also find | |
188 | documentation for third-party modules there. | |
189 | ||
190 | You should be able to view Perl's documentation with your man(1) | |
191 | program by including the proper directories in the appropriate start-up | |
192 | files, or in the MANPATH environment variable. To find out where the | |
193 | configuration has installed the manpages, type: | |
194 | ||
195 | perl -V:man.dir | |
196 | ||
197 | If the directories have a common stem, such as F</usr/local/man/man1> | |
198 | and F</usr/local/man/man3>, you need only to add that stem | |
199 | (F</usr/local/man>) to your man(1) configuration files or your MANPATH | |
200 | environment variable. If they do not share a stem, you'll have to add | |
201 | both stems. | |
202 | ||
203 | If that doesn't work for some reason, you can still use the | |
204 | supplied F<perldoc> script to view module information. You might | |
205 | also look into getting a replacement man program. | |
206 | ||
207 | If something strange has gone wrong with your program and you're not | |
208 | sure where you should look for help, try the B<-w> switch first. It | |
209 | will often point out exactly where the trouble is. | |
210 | ||
211 | =head1 DESCRIPTION | |
212 | ||
213 | Perl is a language optimized for scanning arbitrary | |
214 | text files, extracting information from those text files, and printing | |
215 | reports based on that information. It's also a good language for many | |
216 | system management tasks. The language is intended to be practical | |
217 | (easy to use, efficient, complete) rather than beautiful (tiny, | |
218 | elegant, minimal). | |
219 | ||
220 | Perl combines (in the author's opinion, anyway) some of the best | |
221 | features of C, B<sed>, B<awk>, and B<sh>, so people familiar with | |
222 | those languages should have little difficulty with it. (Language | |
223 | historians will also note some vestiges of B<csh>, Pascal, and even | |
224 | BASIC-PLUS.) Expression syntax corresponds closely to C | |
225 | expression syntax. Unlike most Unix utilities, Perl does not | |
226 | arbitrarily limit the size of your data--if you've got the memory, | |
227 | Perl can slurp in your whole file as a single string. Recursion is of | |
228 | unlimited depth. And the tables used by hashes (sometimes called | |
229 | "associative arrays") grow as necessary to prevent degraded | |
230 | performance. Perl can use sophisticated pattern matching techniques to | |
231 | scan large amounts of data quickly. Although optimized for | |
232 | scanning text, Perl can also deal with binary data, and can make dbm | |
233 | files look like hashes. Setuid Perl scripts are safer than C programs | |
234 | through a dataflow tracing mechanism that prevents many stupid | |
235 | security holes. | |
236 | ||
237 | If you have a problem that would ordinarily use B<sed> or B<awk> or | |
238 | B<sh>, but it exceeds their capabilities or must run a little faster, | |
239 | and you don't want to write the silly thing in C, then Perl may be for | |
240 | you. There are also translators to turn your B<sed> and B<awk> | |
241 | scripts into Perl scripts. | |
242 | ||
243 | But wait, there's more... | |
244 | ||
245 | Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete | |
246 | rewrite that provides the following additional benefits: | |
247 | ||
248 | =over 4 | |
249 | ||
250 | =item * | |
251 | ||
252 | modularity and reusability using innumerable modules | |
253 | ||
254 | Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>. | |
255 | ||
256 | =item * | |
257 | ||
258 | embeddable and extensible | |
259 | ||
260 | Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>, | |
261 | L<perlguts>, and L<xsubpp>. | |
262 | ||
263 | =item * | |
264 | ||
265 | roll-your-own magic variables (including multiple simultaneous DBM implementations) | |
266 | ||
267 | Described in L<perltie> and L<AnyDBM_File>. | |
268 | ||
269 | =item * | |
270 | ||
271 | subroutines can now be overridden, autoloaded, and prototyped | |
272 | ||
273 | Described in L<perlsub>. | |
274 | ||
275 | =item * | |
276 | ||
277 | arbitrarily nested data structures and anonymous functions | |
278 | ||
279 | Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>. | |
280 | ||
281 | =item * | |
282 | ||
283 | object-oriented programming | |
284 | ||
285 | Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>, | |
286 | and L<perlbot>. | |
287 | ||
288 | =item * | |
289 | ||
290 | compilability into C code or Perl bytecode | |
291 | ||
292 | Described in L<B> and L<B::Bytecode>. | |
293 | ||
294 | =item * | |
295 | ||
296 | support for light-weight processes (threads) | |
297 | ||
298 | Described in L<perlthrtut> and L<Thread>. | |
299 | ||
300 | =item * | |
301 | ||
302 | support for internationalization, localization, and Unicode | |
303 | ||
304 | Described in L<perllocale> and L<utf8>. | |
305 | ||
306 | =item * | |
307 | ||
308 | lexical scoping | |
309 | ||
310 | Described in L<perlsub>. | |
311 | ||
312 | =item * | |
313 | ||
314 | regular expression enhancements | |
315 | ||
316 | Described in L<perlre>, with additional examples in L<perlop>. | |
317 | ||
318 | =item * | |
319 | ||
320 | enhanced debugger and interactive Perl environment, | |
321 | with integrated editor support | |
322 | ||
323 | Described in L<perldebtut>, L<perldebug> and L<perldebguts>. | |
324 | ||
325 | =item * | |
326 | ||
327 | POSIX 1003.1 compliant library | |
328 | ||
329 | Described in L<POSIX>. | |
330 | ||
331 | =back | |
332 | ||
333 | Okay, that's I<definitely> enough hype. | |
334 | ||
335 | =head1 AVAILABILITY | |
336 | ||
337 | Perl is available for most operating systems, including virtually | |
338 | all Unix-like platforms. See L<perlport/"Supported Platforms"> | |
339 | for a listing. | |
340 | ||
341 | =head1 ENVIRONMENT | |
342 | ||
343 | See L<perlrun>. | |
344 | ||
345 | =head1 AUTHOR | |
346 | ||
347 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. | |
348 | ||
349 | If your Perl success stories and testimonials may be of help to others | |
350 | who wish to advocate the use of Perl in their applications, | |
351 | or if you wish to simply express your gratitude to Larry and the | |
352 | Perl developers, please write to perl-thanks@perl.org . | |
353 | ||
354 | =head1 FILES | |
355 | ||
356 | "@INC" locations of perl libraries | |
357 | ||
358 | =head1 SEE ALSO | |
359 | ||
360 | a2p awk to perl translator | |
361 | s2p sed to perl translator | |
362 | ||
363 | http://www.perl.com/ the Perl Home Page | |
364 | http://www.cpan.org/ the Comprehensive Perl Archive | |
365 | http://www.perl.org/ Perl Mongers (Perl user groups) | |
366 | ||
367 | =head1 DIAGNOSTICS | |
368 | ||
369 | The C<use warnings> pragma (and the B<-w> switch) produces some | |
370 | lovely diagnostics. | |
371 | ||
372 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use | |
373 | diagnostics> pragma automatically turns Perl's normally terse warnings | |
374 | and errors into these longer forms. | |
375 | ||
376 | Compilation errors will tell you the line number of the error, with an | |
377 | indication of the next token or token type that was to be examined. | |
378 | (In a script passed to Perl via B<-e> switches, each | |
379 | B<-e> is counted as one line.) | |
380 | ||
381 | Setuid scripts have additional constraints that can produce error | |
382 | messages such as "Insecure dependency". See L<perlsec>. | |
383 | ||
384 | Did we mention that you should definitely consider using the B<-w> | |
385 | switch? | |
386 | ||
387 | =head1 BUGS | |
388 | ||
389 | The B<-w> switch is not mandatory. | |
390 | ||
391 | Perl is at the mercy of your machine's definitions of various | |
392 | operations such as type casting, atof(), and floating-point | |
393 | output with sprintf(). | |
394 | ||
395 | If your stdio requires a seek or eof between reads and writes on a | |
396 | particular stream, so does Perl. (This doesn't apply to sysread() | |
397 | and syswrite().) | |
398 | ||
399 | While none of the built-in data types have any arbitrary size limits | |
400 | (apart from memory size), there are still a few arbitrary limits: a | |
401 | given variable name may not be longer than 251 characters. Line numbers | |
402 | displayed by diagnostics are internally stored as short integers, | |
403 | so they are limited to a maximum of 65535 (higher numbers usually being | |
404 | affected by wraparound). | |
405 | ||
406 | You may mail your bug reports (be sure to include full configuration | |
407 | information as output by the myconfig program in the perl source | |
408 | tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded | |
409 | in compiling perl, the B<perlbug> script in the F<utils/> subdirectory | |
410 | can be used to help mail in a bug report. | |
411 | ||
412 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but | |
413 | don't tell anyone I said that. | |
414 | ||
415 | =head1 NOTES | |
416 | ||
417 | The Perl motto is "There's more than one way to do it." Divining | |
418 | how many more is left as an exercise to the reader. | |
419 | ||
420 | The three principal virtues of a programmer are Laziness, | |
421 | Impatience, and Hubris. See the Camel Book for why. | |
422 |