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a0d0e21e LW |
1 | =head1 NAME |
2 | ||
3 | perl - Practical Extraction and Report Language | |
4 | ||
5 | =head1 SYNOPSIS | |
6 | ||
19799a22 GS |
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> ]...> | |
c07a80fd | 14 | |
14218588 GS |
15 | For ease of access, the Perl manual has been split up into several |
16 | sections: | |
a0d0e21e | 17 | |
fb9cefb4 GS |
18 | perl Perl overview (this section) |
19 | perldelta Perl changes since previous version | |
9bc80687 GS |
20 | perl5005delta Perl changes in version 5.005 |
21 | perl5004delta Perl changes in version 5.004 | |
fb9cefb4 GS |
22 | perlfaq Perl frequently asked questions |
23 | perltoc Perl documentation table of contents | |
760ac839 | 24 | |
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25 | perldata Perl data structures |
26 | perlsyn Perl syntax | |
27 | perlop Perl operators and precedence | |
28 | perlre Perl regular expressions | |
29 | perlrun Perl execution and options | |
30 | perlfunc Perl builtin functions | |
2605996a | 31 | perlopentut Perl open() tutorial |
fb9cefb4 GS |
32 | perlvar Perl predefined variables |
33 | perlsub Perl subroutines | |
34 | perlmod Perl modules: how they work | |
35 | perlmodlib Perl modules: how to write and use | |
36 | perlmodinstall Perl modules: how to install from CPAN | |
37 | perlform Perl formats | |
38 | perllocale Perl locale support | |
760ac839 | 39 | |
a1e2a320 | 40 | perlreftut Perl references short introduction |
19799a22 | 41 | perlref Perl references, the rest of the story |
fb9cefb4 | 42 | perldsc Perl data structures intro |
19799a22 | 43 | perllol Perl data structures: arrays of arrays |
694468e3 | 44 | perlboot Perl OO tutorial for beginners |
19799a22 GS |
45 | perltoot Perl OO tutorial, part 1 |
46 | perltootc Perl OO tutorial, part 2 | |
fb9cefb4 GS |
47 | perlobj Perl objects |
48 | perltie Perl objects hidden behind simple variables | |
49 | perlbot Perl OO tricks and examples | |
50 | perlipc Perl interprocess communication | |
7766f137 | 51 | perlfork Perl fork() information |
2605996a | 52 | perlthrtut Perl threads tutorial |
9fe6733a | 53 | perldbmfilter Perl DBM Filters |
760ac839 | 54 | |
54a137f5 | 55 | perlcompile Perl compiler suite intro |
fb9cefb4 GS |
56 | perldebug Perl debugging |
57 | perldiag Perl diagnostic messages | |
ac65edd0 | 58 | perlnumber Perl number semantics |
fb9cefb4 GS |
59 | perlsec Perl security |
60 | perltrap Perl traps for the unwary | |
61 | perlport Perl portability guide | |
62 | perlstyle Perl style guide | |
760ac839 | 63 | |
fb9cefb4 GS |
64 | perlpod Perl plain old documentation |
65 | perlbook Perl book information | |
760ac839 | 66 | |
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67 | perlembed Perl ways to embed perl in your C or C++ application |
68 | perlapio Perl internal IO abstraction interface | |
69 | perlxs Perl XS application programming interface | |
70 | perlxstut Perl XS tutorial | |
71 | perlguts Perl internal functions for those doing extensions | |
72 | perlcall Perl calling conventions from C | |
954c1994 GS |
73 | perlapi Perl API listing (autogenerated) |
74 | perlintern Perl internal functions (autogenerated) | |
a0d0e21e | 75 | |
e50bb9a1 | 76 | perltodo Perl things to do |
e8cd7eae | 77 | perlhack Perl hackers guide |
fb9cefb4 | 78 | perlhist Perl history records |
d516a115 | 79 | |
a0d0e21e LW |
80 | (If you're intending to read these straight through for the first time, |
81 | the suggested order will tend to reduce the number of forward references.) | |
82 | ||
19799a22 | 83 | By default, the manpages listed above are installed in the |
fc952dec CS |
84 | F</usr/local/man/> directory. |
85 | ||
86 | Extensive additional documentation for Perl modules is available. The | |
87 | default configuration for perl will place this additional documentation | |
88 | in the F</usr/local/lib/perl5/man> directory (or else in the F<man> | |
89 | subdirectory of the Perl library directory). Some of this additional | |
90 | documentation is distributed standard with Perl, but you'll also find | |
91 | documentation for third-party modules there. | |
92 | ||
93 | You should be able to view Perl's documentation with your man(1) | |
94 | program by including the proper directories in the appropriate start-up | |
95 | files, or in the MANPATH environment variable. To find out where the | |
96 | configuration has installed the manpages, type: | |
16d20bd9 | 97 | |
760ac839 | 98 | perl -V:man.dir |
16d20bd9 | 99 | |
fc952dec CS |
100 | If the directories have a common stem, such as F</usr/local/man/man1> |
101 | and F</usr/local/man/man3>, you need only to add that stem | |
102 | (F</usr/local/man>) to your man(1) configuration files or your MANPATH | |
103 | environment variable. If they do not share a stem, you'll have to add | |
104 | both stems. | |
16d20bd9 AD |
105 | |
106 | If that doesn't work for some reason, you can still use the | |
4633a7c4 LW |
107 | supplied F<perldoc> script to view module information. You might |
108 | also look into getting a replacement man program. | |
16d20bd9 | 109 | |
a0d0e21e LW |
110 | If something strange has gone wrong with your program and you're not |
111 | sure where you should look for help, try the B<-w> switch first. It | |
112 | will often point out exactly where the trouble is. | |
113 | ||
114 | =head1 DESCRIPTION | |
115 | ||
5f05dabc | 116 | Perl is a language optimized for scanning arbitrary |
a0d0e21e LW |
117 | text files, extracting information from those text files, and printing |
118 | reports based on that information. It's also a good language for many | |
119 | system management tasks. The language is intended to be practical | |
120 | (easy to use, efficient, complete) rather than beautiful (tiny, | |
94d58c47 | 121 | elegant, minimal). |
122 | ||
aa689395 | 123 | Perl combines (in the author's opinion, anyway) some of the best |
124 | features of C, B<sed>, B<awk>, and B<sh>, so people familiar with | |
125 | those languages should have little difficulty with it. (Language | |
126 | historians will also note some vestiges of B<csh>, Pascal, and even | |
14218588 | 127 | BASIC-PLUS.) Expression syntax corresponds closely to C |
a0d0e21e LW |
128 | expression syntax. Unlike most Unix utilities, Perl does not |
129 | arbitrarily limit the size of your data--if you've got the memory, | |
aa689395 | 130 | Perl can slurp in your whole file as a single string. Recursion is of |
0f31cffe | 131 | unlimited depth. And the tables used by hashes (sometimes called |
aa689395 | 132 | "associative arrays") grow as necessary to prevent degraded |
0f31cffe | 133 | performance. Perl can use sophisticated pattern matching techniques to |
14218588 | 134 | scan large amounts of data quickly. Although optimized for |
aa689395 | 135 | scanning text, Perl can also deal with binary data, and can make dbm |
136 | files look like hashes. Setuid Perl scripts are safer than C programs | |
14218588 | 137 | through a dataflow tracing mechanism that prevents many stupid |
aa689395 | 138 | security holes. |
139 | ||
140 | If you have a problem that would ordinarily use B<sed> or B<awk> or | |
141 | B<sh>, but it exceeds their capabilities or must run a little faster, | |
142 | and you don't want to write the silly thing in C, then Perl may be for | |
143 | you. There are also translators to turn your B<sed> and B<awk> | |
144 | scripts into Perl scripts. | |
a0d0e21e LW |
145 | |
146 | But wait, there's more... | |
147 | ||
19799a22 GS |
148 | Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete |
149 | rewrite that provides the following additional benefits: | |
a0d0e21e | 150 | |
19799a22 | 151 | =over |
a0d0e21e | 152 | |
19799a22 | 153 | =item * modularity and reusability using innumerable modules |
a0d0e21e | 154 | |
19799a22 | 155 | Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>. |
a0d0e21e | 156 | |
19799a22 | 157 | =item * embeddable and extensible |
a0d0e21e | 158 | |
19799a22 GS |
159 | Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>, |
160 | L<perlguts>, and L<xsubpp>. | |
a0d0e21e | 161 | |
19799a22 | 162 | =item * roll-your-own magic variables (including multiple simultaneous DBM implementations) |
a0d0e21e | 163 | |
19799a22 | 164 | Described in L<perltie> and L<AnyDBM_File>. |
a0d0e21e | 165 | |
19799a22 | 166 | =item * subroutines can now be overridden, autoloaded, and prototyped |
a0d0e21e | 167 | |
19799a22 | 168 | Described in L<perlsub>. |
a0d0e21e | 169 | |
19799a22 | 170 | =item * arbitrarily nested data structures and anonymous functions |
a0d0e21e | 171 | |
19799a22 | 172 | Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>. |
a0d0e21e | 173 | |
19799a22 | 174 | =item * object-oriented programming |
a0d0e21e | 175 | |
19799a22 | 176 | Described in L<perlobj>, L<perltoot>, and L<perlbot>. |
a0d0e21e | 177 | |
19799a22 | 178 | =item * compilability into C code or Perl bytecode |
a0d0e21e | 179 | |
19799a22 | 180 | Described in L<B> and L<B::Bytecode>. |
a0d0e21e | 181 | |
19799a22 | 182 | =item * support for light-weight processes (threads) |
a0d0e21e | 183 | |
19799a22 | 184 | Described in L<perlthrtut> and L<Thread>. |
a0d0e21e | 185 | |
19799a22 | 186 | =item * support for internationalization, localization, and Unicode |
a0d0e21e | 187 | |
19799a22 | 188 | Described in L<perllocale> and L<utf8>. |
a0d0e21e | 189 | |
19799a22 | 190 | =item * lexical scoping |
a0d0e21e | 191 | |
19799a22 | 192 | Described in L<perlsub>. |
a0d0e21e | 193 | |
19799a22 | 194 | =item * regular expression enhancements |
a0d0e21e | 195 | |
19799a22 | 196 | Described in L<perlre>, with additional examples in L<perlop>. |
a0d0e21e | 197 | |
14218588 | 198 | =item * enhanced debugger and interactive Perl environment, with integrated editor support |
a0d0e21e | 199 | |
19799a22 | 200 | Described in L<perldebug>. |
a0d0e21e | 201 | |
19799a22 | 202 | =item * POSIX 1003.1 compliant library |
5f05dabc | 203 | |
19799a22 | 204 | Described in L<POSIX>. |
5f05dabc | 205 | |
a0d0e21e LW |
206 | =back |
207 | ||
68dc0745 | 208 | Okay, that's I<definitely> enough hype. |
a0d0e21e | 209 | |
8e465e4e JH |
210 | =head1 AVAILABILITY |
211 | ||
14218588 GS |
212 | Perl is available for most operating systems, including virtually |
213 | all Unix-like platforms. | |
8e465e4e | 214 | |
14218588 GS |
215 | As of May 1999, the following platforms are able to build Perl |
216 | from the standard source code distribution available at | |
19799a22 | 217 | http://www.perl.com/CPAN/src/index.html |
8e465e4e | 218 | |
58493fc4 JH |
219 | AIX Linux SCO ODT/OSR |
220 | A/UX MachTen Solaris | |
221 | BeOS MPE/iX SunOS | |
222 | BSD/OS NetBSD SVR4 | |
223 | DG/UX NextSTEP Tru64 UNIX 3) | |
224 | DomainOS OpenBSD Ultrix | |
225 | DOS DJGPP 1) OpenSTEP UNICOS | |
226 | DYNIX/ptx OS/2 VMS | |
227 | FreeBSD OS390 2) VOS | |
228 | HP-UX PowerMAX Windows 3.1 1) | |
229 | Hurd QNX Windows 95 1) 4) | |
230 | IRIX Windows 98 1) 4) | |
231 | Windows NT 1) 4) | |
8e465e4e JH |
232 | |
233 | 1) in DOS mode either the DOS or OS/2 ports can be used | |
58493fc4 JH |
234 | 2) formerly known as MVS |
235 | 3) formerly known as Digital UNIX and before that DEC OSF/1 | |
873b149f | 236 | 4) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++ |
58493fc4 | 237 | |
14218588 GS |
238 | The following platforms have been known to build Perl from source, |
239 | but we haven't been able to verify their status for the current release, | |
240 | either because the hardware/software platforms are rare or | |
19799a22 | 241 | because we don't have an active champion on these platforms--or both. |
8e465e4e JH |
242 | |
243 | 3b1 FPS Plan 9 | |
04251ce8 JH |
244 | AmigaOS GENIX PowerUX |
245 | ConvexOS Greenhills RISC/os | |
246 | CX/UX ISC Stellar | |
247 | DC/OSx MachTen 68k SVR2 | |
248 | DDE SMES MiNT TI1500 | |
82cda36e JH |
249 | DOS EMX MPC TitanOS |
250 | Dynix NEWS-OS UNICOS/mk | |
251 | EP/IX Opus Unisys Dynix | |
252 | ESIX Unixware | |
8e465e4e | 253 | |
14218588 GS |
254 | Support for the following platforms is planned for the next major |
255 | Perl release. | |
8e465e4e JH |
256 | |
257 | BS2000 | |
00ad96e1 JH |
258 | Netware |
259 | Rhapsody | |
8e465e4e JH |
260 | VM/ESA |
261 | ||
262 | The following platforms have their own source code distributions and | |
19799a22 | 263 | binaries available via http://www.perl.com/CPAN/ports/index.html. |
8e465e4e JH |
264 | |
265 | Perl release | |
266 | ||
267 | AS/400 5.003 | |
2e04d155 | 268 | MacOS 5.004 |
04251ce8 | 269 | Netware 5.003_07 |
8e465e4e JH |
270 | Tandem Guardian 5.004 |
271 | ||
272 | The following platforms have only binaries available via | |
19799a22 | 273 | http://www.perl.com/CPAN/ports/index.html. |
8e465e4e JH |
274 | |
275 | Perl release | |
276 | ||
d845c4a6 | 277 | Acorn RISCOS 5.005_02 |
8e465e4e JH |
278 | AOS 5.002 |
279 | LynxOS 5.004_02 | |
8e465e4e | 280 | |
a0d0e21e LW |
281 | =head1 ENVIRONMENT |
282 | ||
1e422769 | 283 | See L<perlrun>. |
a0d0e21e LW |
284 | |
285 | =head1 AUTHOR | |
286 | ||
19799a22 | 287 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. |
a0d0e21e | 288 | |
a99b1639 TP |
289 | If your Perl success stories and testimonials may be of help to others |
290 | who wish to advocate the use of Perl in their applications, | |
291 | or if you wish to simply express your gratitude to Larry and the | |
19799a22 | 292 | Perl developers, please write to perl-thanks@perl.org . |
a99b1639 | 293 | |
a0d0e21e LW |
294 | =head1 FILES |
295 | ||
5f05dabc | 296 | "@INC" locations of perl libraries |
a0d0e21e LW |
297 | |
298 | =head1 SEE ALSO | |
299 | ||
300 | a2p awk to perl translator | |
301 | s2p sed to perl translator | |
302 | ||
19799a22 | 303 | http://www.perl.com/ the Perl Home Page |
5a3e7812 | 304 | http://www.perl.com/CPAN the Comprehensive Perl Archive |
19799a22 | 305 | |
a0d0e21e LW |
306 | =head1 DIAGNOSTICS |
307 | ||
308 | The B<-w> switch produces some lovely diagnostics. | |
309 | ||
5a964f20 TC |
310 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use |
311 | diagnostics> pragma automatically turns Perl's normally terse warnings | |
312 | and errors into these longer forms. | |
a0d0e21e LW |
313 | |
314 | Compilation errors will tell you the line number of the error, with an | |
315 | indication of the next token or token type that was to be examined. | |
14218588 | 316 | (In a script passed to Perl via B<-e> switches, each |
a0d0e21e LW |
317 | B<-e> is counted as one line.) |
318 | ||
319 | Setuid scripts have additional constraints that can produce error | |
320 | messages such as "Insecure dependency". See L<perlsec>. | |
321 | ||
322 | Did we mention that you should definitely consider using the B<-w> | |
323 | switch? | |
324 | ||
325 | =head1 BUGS | |
326 | ||
327 | The B<-w> switch is not mandatory. | |
328 | ||
329 | Perl is at the mercy of your machine's definitions of various | |
1b3f7d21 CS |
330 | operations such as type casting, atof(), and floating-point |
331 | output with sprintf(). | |
a0d0e21e | 332 | |
748a9306 | 333 | If your stdio requires a seek or eof between reads and writes on a |
a0d0e21e LW |
334 | particular stream, so does Perl. (This doesn't apply to sysread() |
335 | and syswrite().) | |
336 | ||
337 | While none of the built-in data types have any arbitrary size limits | |
338 | (apart from memory size), there are still a few arbitrary limits: a | |
a30ac152 GS |
339 | given variable name may not be longer than 251 characters. Line numbers |
340 | displayed by diagnostics are internally stored as short integers, | |
341 | so they are limited to a maximum of 65535 (higher numbers usually being | |
342 | affected by wraparound). | |
a0d0e21e | 343 | |
b0607b7a | 344 | You may mail your bug reports (be sure to include full configuration |
19799a22 GS |
345 | information as output by the myconfig program in the perl source |
346 | tree, or by C<perl -V>) to perlbug@perl.com . If you've succeeded | |
347 | in compiling perl, the perlbug script in the utils/ subdirectory | |
348 | can be used to help mail in a bug report. | |
4633a7c4 | 349 | |
a0d0e21e LW |
350 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but |
351 | don't tell anyone I said that. | |
352 | ||
353 | =head1 NOTES | |
354 | ||
355 | The Perl motto is "There's more than one way to do it." Divining | |
356 | how many more is left as an exercise to the reader. | |
357 | ||
4633a7c4 | 358 | The three principal virtues of a programmer are Laziness, |
a0d0e21e | 359 | Impatience, and Hubris. See the Camel Book for why. |
16d20bd9 | 360 |