Commit | Line | Data |
---|---|---|
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 | |
4755096e | 15 | For ease of access, the Perl manual has been split up into several sections: |
a0d0e21e | 16 | |
fb9cefb4 | 17 | perl Perl overview (this section) |
fb9cefb4 GS |
18 | perlfaq Perl frequently asked questions |
19 | perltoc Perl documentation table of contents | |
4755096e | 20 | perlbook Perl book information |
760ac839 | 21 | |
fb9cefb4 | 22 | perlsyn Perl syntax |
4755096e | 23 | perldata Perl data structures |
fb9cefb4 | 24 | perlop Perl operators and precedence |
c2e66d9e GS |
25 | perlsub Perl subroutines |
26 | perlfunc Perl builtin functions | |
4755096e GS |
27 | perlreftut Perl references short introduction |
28 | perldsc Perl data structures intro | |
4755096e | 29 | perlrequick Perl regular expressions quick start |
c2e66d9e GS |
30 | perlpod Perl plain old documentation |
31 | perlstyle Perl style guide | |
32 | perltrap Perl traps for the unwary | |
4755096e | 33 | |
c2e66d9e GS |
34 | perlrun Perl execution and options |
35 | perldiag Perl diagnostic messages | |
4755096e | 36 | perllexwarn Perl warnings and their control |
10862624 | 37 | perldebtut Perl debugging tutorial |
4755096e GS |
38 | perldebug Perl debugging |
39 | ||
fb9cefb4 | 40 | perlvar Perl predefined variables |
c2e66d9e GS |
41 | perllol Perl data structures: arrays of arrays |
42 | perlopentut Perl open() tutorial | |
43 | perlretut Perl regular expressions tutorial | |
2e1d04bc | 44 | |
4755096e | 45 | perlre Perl regular expressions, the rest of the story |
d396a558 JH |
46 | perlref Perl references, the rest of the story |
47 | ||
fb9cefb4 | 48 | perlform Perl formats |
d396a558 JH |
49 | |
50 | perlboot Perl OO tutorial for beginners | |
51 | perltoot Perl OO tutorial, part 1 | |
52 | perltootc Perl OO tutorial, part 2 | |
53 | perlobj Perl objects | |
54 | perlbot Perl OO tricks and examples | |
55 | perltie Perl objects hidden behind simple variables | |
760ac839 | 56 | |
c2e66d9e GS |
57 | perlipc Perl interprocess communication |
58 | perlfork Perl fork() information | |
59 | perlnumber Perl number semantics | |
60 | perlthrtut Perl threads tutorial | |
61 | ||
62 | perlport Perl portability guide | |
d396a558 JH |
63 | perllocale Perl locale support |
64 | perlunicode Perl unicode support | |
65 | perlebcdic Considerations for running Perl on EBCDIC platforms | |
c2e66d9e | 66 | |
d396a558 | 67 | perlsec Perl security |
4755096e | 68 | |
c2e66d9e GS |
69 | perlmod Perl modules: how they work |
70 | perlmodlib Perl modules: how to write and use | |
71 | perlmodinstall Perl modules: how to install from CPAN | |
72 | perlnewmod Perl modules: preparing a new module for distribution | |
760ac839 | 73 | |
4755096e GS |
74 | perlfaq1 General Questions About Perl |
75 | perlfaq2 Obtaining and Learning about Perl | |
76 | perlfaq3 Programming Tools | |
77 | perlfaq4 Data Manipulation | |
78 | perlfaq5 Files and Formats | |
79 | perlfaq6 Regexes | |
80 | perlfaq7 Perl Language Issues | |
81 | perlfaq8 System Interaction | |
82 | perlfaq9 Networking | |
760ac839 | 83 | |
4755096e | 84 | perlcompile Perl compiler suite intro |
760ac839 | 85 | |
fb9cefb4 | 86 | perlembed Perl ways to embed perl in your C or C++ application |
055fd3a9 | 87 | perldebguts Perl debugging guts and tips |
fb9cefb4 | 88 | perlxstut Perl XS tutorial |
4755096e | 89 | perlxs Perl XS application programming interface |
fb9cefb4 GS |
90 | perlguts Perl internal functions for those doing extensions |
91 | perlcall Perl calling conventions from C | |
4755096e GS |
92 | perlutil utilities packaged with the Perl distribution |
93 | perlfilter Perl source filters | |
94 | perldbmfilter Perl DBM filters | |
954c1994 GS |
95 | perlapi Perl API listing (autogenerated) |
96 | perlintern Perl internal functions (autogenerated) | |
4755096e | 97 | perlapio Perl internal IO abstraction interface |
e50bb9a1 | 98 | perltodo Perl things to do |
e8cd7eae | 99 | perlhack Perl hackers guide |
4755096e | 100 | |
fb9cefb4 | 101 | perlhist Perl history records |
4755096e GS |
102 | perldelta Perl changes since previous version |
103 | perl56delta Perl changes in version 5.6 | |
104 | perl5005delta Perl changes in version 5.005 | |
105 | perl5004delta Perl changes in version 5.004 | |
d516a115 | 106 | |
37d4d706 | 107 | perlaix Perl notes for AIX |
49877630 GS |
108 | perlamiga Perl notes for Amiga |
109 | perlcygwin Perl notes for Cygwin | |
110 | perldos Perl notes for DOS | |
9a997319 | 111 | perlepoc Perl notes for EPOC |
49877630 | 112 | perlhpux Perl notes for HP-UX |
da369004 | 113 | perlmachten Perl notes for Power MachTen |
ab648d5e | 114 | perlmpeix Perl notes for MPE/iX |
49877630 GS |
115 | perlos2 Perl notes for OS/2 |
116 | perlos390 Perl notes for OS/390 | |
c2e66d9e | 117 | perlposix-bc Perl notes for POSIX-BC |
d420ca49 | 118 | perlsolaris Perl notes for Solaris |
49877630 | 119 | perlvms Perl notes for VMS |
9a997319 | 120 | perlvos Perl notes for Stratus VOS |
49877630 GS |
121 | perlwin32 Perl notes for Windows |
122 | ||
a0d0e21e LW |
123 | (If you're intending to read these straight through for the first time, |
124 | the suggested order will tend to reduce the number of forward references.) | |
125 | ||
19799a22 | 126 | By default, the manpages listed above are installed in the |
fc952dec CS |
127 | F</usr/local/man/> directory. |
128 | ||
129 | Extensive additional documentation for Perl modules is available. The | |
130 | default configuration for perl will place this additional documentation | |
131 | in the F</usr/local/lib/perl5/man> directory (or else in the F<man> | |
132 | subdirectory of the Perl library directory). Some of this additional | |
133 | documentation is distributed standard with Perl, but you'll also find | |
134 | documentation for third-party modules there. | |
135 | ||
136 | You should be able to view Perl's documentation with your man(1) | |
137 | program by including the proper directories in the appropriate start-up | |
138 | files, or in the MANPATH environment variable. To find out where the | |
139 | configuration has installed the manpages, type: | |
16d20bd9 | 140 | |
760ac839 | 141 | perl -V:man.dir |
16d20bd9 | 142 | |
fc952dec CS |
143 | If the directories have a common stem, such as F</usr/local/man/man1> |
144 | and F</usr/local/man/man3>, you need only to add that stem | |
145 | (F</usr/local/man>) to your man(1) configuration files or your MANPATH | |
146 | environment variable. If they do not share a stem, you'll have to add | |
147 | both stems. | |
16d20bd9 AD |
148 | |
149 | If that doesn't work for some reason, you can still use the | |
4633a7c4 LW |
150 | supplied F<perldoc> script to view module information. You might |
151 | also look into getting a replacement man program. | |
16d20bd9 | 152 | |
a0d0e21e LW |
153 | If something strange has gone wrong with your program and you're not |
154 | sure where you should look for help, try the B<-w> switch first. It | |
155 | will often point out exactly where the trouble is. | |
156 | ||
157 | =head1 DESCRIPTION | |
158 | ||
5f05dabc | 159 | Perl is a language optimized for scanning arbitrary |
a0d0e21e LW |
160 | text files, extracting information from those text files, and printing |
161 | reports based on that information. It's also a good language for many | |
162 | system management tasks. The language is intended to be practical | |
163 | (easy to use, efficient, complete) rather than beautiful (tiny, | |
94d58c47 | 164 | elegant, minimal). |
165 | ||
aa689395 | 166 | Perl combines (in the author's opinion, anyway) some of the best |
167 | features of C, B<sed>, B<awk>, and B<sh>, so people familiar with | |
168 | those languages should have little difficulty with it. (Language | |
169 | historians will also note some vestiges of B<csh>, Pascal, and even | |
14218588 | 170 | BASIC-PLUS.) Expression syntax corresponds closely to C |
a0d0e21e LW |
171 | expression syntax. Unlike most Unix utilities, Perl does not |
172 | arbitrarily limit the size of your data--if you've got the memory, | |
aa689395 | 173 | Perl can slurp in your whole file as a single string. Recursion is of |
0f31cffe | 174 | unlimited depth. And the tables used by hashes (sometimes called |
aa689395 | 175 | "associative arrays") grow as necessary to prevent degraded |
0f31cffe | 176 | performance. Perl can use sophisticated pattern matching techniques to |
14218588 | 177 | scan large amounts of data quickly. Although optimized for |
aa689395 | 178 | scanning text, Perl can also deal with binary data, and can make dbm |
179 | files look like hashes. Setuid Perl scripts are safer than C programs | |
14218588 | 180 | through a dataflow tracing mechanism that prevents many stupid |
aa689395 | 181 | security holes. |
182 | ||
183 | If you have a problem that would ordinarily use B<sed> or B<awk> or | |
184 | B<sh>, but it exceeds their capabilities or must run a little faster, | |
185 | and you don't want to write the silly thing in C, then Perl may be for | |
186 | you. There are also translators to turn your B<sed> and B<awk> | |
187 | scripts into Perl scripts. | |
a0d0e21e LW |
188 | |
189 | But wait, there's more... | |
190 | ||
19799a22 GS |
191 | Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete |
192 | rewrite that provides the following additional benefits: | |
a0d0e21e | 193 | |
13a2d996 | 194 | =over 4 |
a0d0e21e | 195 | |
551e1d92 RB |
196 | =item * |
197 | ||
198 | modularity and reusability using innumerable modules | |
a0d0e21e | 199 | |
19799a22 | 200 | Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>. |
a0d0e21e | 201 | |
551e1d92 RB |
202 | =item * |
203 | ||
204 | embeddable and extensible | |
a0d0e21e | 205 | |
19799a22 GS |
206 | Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>, |
207 | L<perlguts>, and L<xsubpp>. | |
a0d0e21e | 208 | |
551e1d92 RB |
209 | =item * |
210 | ||
211 | roll-your-own magic variables (including multiple simultaneous DBM implementations) | |
a0d0e21e | 212 | |
19799a22 | 213 | Described in L<perltie> and L<AnyDBM_File>. |
a0d0e21e | 214 | |
551e1d92 RB |
215 | =item * |
216 | ||
217 | subroutines can now be overridden, autoloaded, and prototyped | |
a0d0e21e | 218 | |
19799a22 | 219 | Described in L<perlsub>. |
a0d0e21e | 220 | |
551e1d92 RB |
221 | =item * |
222 | ||
223 | arbitrarily nested data structures and anonymous functions | |
a0d0e21e | 224 | |
19799a22 | 225 | Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>. |
a0d0e21e | 226 | |
551e1d92 RB |
227 | =item * |
228 | ||
229 | object-oriented programming | |
a0d0e21e | 230 | |
19799a22 | 231 | Described in L<perlobj>, L<perltoot>, and L<perlbot>. |
a0d0e21e | 232 | |
551e1d92 RB |
233 | =item * |
234 | ||
235 | compilability into C code or Perl bytecode | |
a0d0e21e | 236 | |
19799a22 | 237 | Described in L<B> and L<B::Bytecode>. |
a0d0e21e | 238 | |
551e1d92 RB |
239 | =item * |
240 | ||
241 | support for light-weight processes (threads) | |
a0d0e21e | 242 | |
19799a22 | 243 | Described in L<perlthrtut> and L<Thread>. |
a0d0e21e | 244 | |
551e1d92 RB |
245 | =item * |
246 | ||
247 | support for internationalization, localization, and Unicode | |
a0d0e21e | 248 | |
19799a22 | 249 | Described in L<perllocale> and L<utf8>. |
a0d0e21e | 250 | |
551e1d92 RB |
251 | =item * |
252 | ||
253 | lexical scoping | |
a0d0e21e | 254 | |
19799a22 | 255 | Described in L<perlsub>. |
a0d0e21e | 256 | |
551e1d92 RB |
257 | =item * |
258 | ||
259 | regular expression enhancements | |
a0d0e21e | 260 | |
19799a22 | 261 | Described in L<perlre>, with additional examples in L<perlop>. |
a0d0e21e | 262 | |
551e1d92 RB |
263 | =item * |
264 | ||
265 | enhanced debugger and interactive Perl environment, | |
266 | with integrated editor support | |
a0d0e21e | 267 | |
19799a22 | 268 | Described in L<perldebug>. |
a0d0e21e | 269 | |
551e1d92 RB |
270 | =item * |
271 | ||
272 | POSIX 1003.1 compliant library | |
5f05dabc | 273 | |
19799a22 | 274 | Described in L<POSIX>. |
5f05dabc | 275 | |
a0d0e21e LW |
276 | =back |
277 | ||
68dc0745 | 278 | Okay, that's I<definitely> enough hype. |
a0d0e21e | 279 | |
8e465e4e JH |
280 | =head1 AVAILABILITY |
281 | ||
14218588 | 282 | Perl is available for most operating systems, including virtually |
055fd3a9 GS |
283 | all Unix-like platforms. See L<perlport/"Supported Platforms"> |
284 | for a listing. | |
8bc4a6bb | 285 | |
a0d0e21e LW |
286 | =head1 ENVIRONMENT |
287 | ||
1e422769 | 288 | See L<perlrun>. |
a0d0e21e LW |
289 | |
290 | =head1 AUTHOR | |
291 | ||
19799a22 | 292 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. |
a0d0e21e | 293 | |
a99b1639 TP |
294 | If your Perl success stories and testimonials may be of help to others |
295 | who wish to advocate the use of Perl in their applications, | |
296 | or if you wish to simply express your gratitude to Larry and the | |
19799a22 | 297 | Perl developers, please write to perl-thanks@perl.org . |
a99b1639 | 298 | |
a0d0e21e LW |
299 | =head1 FILES |
300 | ||
5f05dabc | 301 | "@INC" locations of perl libraries |
a0d0e21e LW |
302 | |
303 | =head1 SEE ALSO | |
304 | ||
305 | a2p awk to perl translator | |
306 | s2p sed to perl translator | |
307 | ||
19799a22 | 308 | http://www.perl.com/ the Perl Home Page |
5a3e7812 | 309 | http://www.perl.com/CPAN the Comprehensive Perl Archive |
19799a22 | 310 | |
a0d0e21e LW |
311 | =head1 DIAGNOSTICS |
312 | ||
9f1b1f2d GS |
313 | The C<use warnings> pragma (and the B<-w> switch) produces some |
314 | lovely diagnostics. | |
a0d0e21e | 315 | |
5a964f20 TC |
316 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use |
317 | diagnostics> pragma automatically turns Perl's normally terse warnings | |
318 | and errors into these longer forms. | |
a0d0e21e LW |
319 | |
320 | Compilation errors will tell you the line number of the error, with an | |
321 | indication of the next token or token type that was to be examined. | |
14218588 | 322 | (In a script passed to Perl via B<-e> switches, each |
a0d0e21e LW |
323 | B<-e> is counted as one line.) |
324 | ||
325 | Setuid scripts have additional constraints that can produce error | |
326 | messages such as "Insecure dependency". See L<perlsec>. | |
327 | ||
328 | Did we mention that you should definitely consider using the B<-w> | |
329 | switch? | |
330 | ||
331 | =head1 BUGS | |
332 | ||
333 | The B<-w> switch is not mandatory. | |
334 | ||
335 | Perl is at the mercy of your machine's definitions of various | |
1b3f7d21 CS |
336 | operations such as type casting, atof(), and floating-point |
337 | output with sprintf(). | |
a0d0e21e | 338 | |
748a9306 | 339 | If your stdio requires a seek or eof between reads and writes on a |
a0d0e21e LW |
340 | particular stream, so does Perl. (This doesn't apply to sysread() |
341 | and syswrite().) | |
342 | ||
343 | While none of the built-in data types have any arbitrary size limits | |
344 | (apart from memory size), there are still a few arbitrary limits: a | |
a30ac152 GS |
345 | given variable name may not be longer than 251 characters. Line numbers |
346 | displayed by diagnostics are internally stored as short integers, | |
347 | so they are limited to a maximum of 65535 (higher numbers usually being | |
348 | affected by wraparound). | |
a0d0e21e | 349 | |
b0607b7a | 350 | You may mail your bug reports (be sure to include full configuration |
19799a22 | 351 | information as output by the myconfig program in the perl source |
7f2de2d2 | 352 | tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded |
055fd3a9 | 353 | in compiling perl, the B<perlbug> script in the F<utils/> subdirectory |
19799a22 | 354 | can be used to help mail in a bug report. |
4633a7c4 | 355 | |
a0d0e21e LW |
356 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but |
357 | don't tell anyone I said that. | |
358 | ||
359 | =head1 NOTES | |
360 | ||
361 | The Perl motto is "There's more than one way to do it." Divining | |
362 | how many more is left as an exercise to the reader. | |
363 | ||
4633a7c4 | 364 | The three principal virtues of a programmer are Laziness, |
a0d0e21e | 365 | Impatience, and Hubris. See the Camel Book for why. |
16d20bd9 | 366 |