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 | |
49877630 GS |
107 | perlamiga Perl notes for Amiga |
108 | perlcygwin Perl notes for Cygwin | |
109 | perldos Perl notes for DOS | |
110 | perlhpux Perl notes for HP-UX | |
da369004 | 111 | perlmachten Perl notes for Power MachTen |
49877630 GS |
112 | perlos2 Perl notes for OS/2 |
113 | perlos390 Perl notes for OS/390 | |
c2e66d9e | 114 | perlposix-bc Perl notes for POSIX-BC |
49877630 GS |
115 | perlvms Perl notes for VMS |
116 | perlwin32 Perl notes for Windows | |
117 | ||
a0d0e21e LW |
118 | (If you're intending to read these straight through for the first time, |
119 | the suggested order will tend to reduce the number of forward references.) | |
120 | ||
19799a22 | 121 | By default, the manpages listed above are installed in the |
fc952dec CS |
122 | F</usr/local/man/> directory. |
123 | ||
124 | Extensive additional documentation for Perl modules is available. The | |
125 | default configuration for perl will place this additional documentation | |
126 | in the F</usr/local/lib/perl5/man> directory (or else in the F<man> | |
127 | subdirectory of the Perl library directory). Some of this additional | |
128 | documentation is distributed standard with Perl, but you'll also find | |
129 | documentation for third-party modules there. | |
130 | ||
131 | You should be able to view Perl's documentation with your man(1) | |
132 | program by including the proper directories in the appropriate start-up | |
133 | files, or in the MANPATH environment variable. To find out where the | |
134 | configuration has installed the manpages, type: | |
16d20bd9 | 135 | |
760ac839 | 136 | perl -V:man.dir |
16d20bd9 | 137 | |
fc952dec CS |
138 | If the directories have a common stem, such as F</usr/local/man/man1> |
139 | and F</usr/local/man/man3>, you need only to add that stem | |
140 | (F</usr/local/man>) to your man(1) configuration files or your MANPATH | |
141 | environment variable. If they do not share a stem, you'll have to add | |
142 | both stems. | |
16d20bd9 AD |
143 | |
144 | If that doesn't work for some reason, you can still use the | |
4633a7c4 LW |
145 | supplied F<perldoc> script to view module information. You might |
146 | also look into getting a replacement man program. | |
16d20bd9 | 147 | |
a0d0e21e LW |
148 | If something strange has gone wrong with your program and you're not |
149 | sure where you should look for help, try the B<-w> switch first. It | |
150 | will often point out exactly where the trouble is. | |
151 | ||
152 | =head1 DESCRIPTION | |
153 | ||
5f05dabc | 154 | Perl is a language optimized for scanning arbitrary |
a0d0e21e LW |
155 | text files, extracting information from those text files, and printing |
156 | reports based on that information. It's also a good language for many | |
157 | system management tasks. The language is intended to be practical | |
158 | (easy to use, efficient, complete) rather than beautiful (tiny, | |
94d58c47 | 159 | elegant, minimal). |
160 | ||
aa689395 | 161 | Perl combines (in the author's opinion, anyway) some of the best |
162 | features of C, B<sed>, B<awk>, and B<sh>, so people familiar with | |
163 | those languages should have little difficulty with it. (Language | |
164 | historians will also note some vestiges of B<csh>, Pascal, and even | |
14218588 | 165 | BASIC-PLUS.) Expression syntax corresponds closely to C |
a0d0e21e LW |
166 | expression syntax. Unlike most Unix utilities, Perl does not |
167 | arbitrarily limit the size of your data--if you've got the memory, | |
aa689395 | 168 | Perl can slurp in your whole file as a single string. Recursion is of |
0f31cffe | 169 | unlimited depth. And the tables used by hashes (sometimes called |
aa689395 | 170 | "associative arrays") grow as necessary to prevent degraded |
0f31cffe | 171 | performance. Perl can use sophisticated pattern matching techniques to |
14218588 | 172 | scan large amounts of data quickly. Although optimized for |
aa689395 | 173 | scanning text, Perl can also deal with binary data, and can make dbm |
174 | files look like hashes. Setuid Perl scripts are safer than C programs | |
14218588 | 175 | through a dataflow tracing mechanism that prevents many stupid |
aa689395 | 176 | security holes. |
177 | ||
178 | If you have a problem that would ordinarily use B<sed> or B<awk> or | |
179 | B<sh>, but it exceeds their capabilities or must run a little faster, | |
180 | and you don't want to write the silly thing in C, then Perl may be for | |
181 | you. There are also translators to turn your B<sed> and B<awk> | |
182 | scripts into Perl scripts. | |
a0d0e21e LW |
183 | |
184 | But wait, there's more... | |
185 | ||
19799a22 GS |
186 | Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete |
187 | rewrite that provides the following additional benefits: | |
a0d0e21e | 188 | |
19799a22 | 189 | =over |
a0d0e21e | 190 | |
19799a22 | 191 | =item * modularity and reusability using innumerable modules |
a0d0e21e | 192 | |
19799a22 | 193 | Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>. |
a0d0e21e | 194 | |
19799a22 | 195 | =item * embeddable and extensible |
a0d0e21e | 196 | |
19799a22 GS |
197 | Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>, |
198 | L<perlguts>, and L<xsubpp>. | |
a0d0e21e | 199 | |
19799a22 | 200 | =item * roll-your-own magic variables (including multiple simultaneous DBM implementations) |
a0d0e21e | 201 | |
19799a22 | 202 | Described in L<perltie> and L<AnyDBM_File>. |
a0d0e21e | 203 | |
19799a22 | 204 | =item * subroutines can now be overridden, autoloaded, and prototyped |
a0d0e21e | 205 | |
19799a22 | 206 | Described in L<perlsub>. |
a0d0e21e | 207 | |
19799a22 | 208 | =item * arbitrarily nested data structures and anonymous functions |
a0d0e21e | 209 | |
19799a22 | 210 | Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>. |
a0d0e21e | 211 | |
19799a22 | 212 | =item * object-oriented programming |
a0d0e21e | 213 | |
19799a22 | 214 | Described in L<perlobj>, L<perltoot>, and L<perlbot>. |
a0d0e21e | 215 | |
19799a22 | 216 | =item * compilability into C code or Perl bytecode |
a0d0e21e | 217 | |
19799a22 | 218 | Described in L<B> and L<B::Bytecode>. |
a0d0e21e | 219 | |
19799a22 | 220 | =item * support for light-weight processes (threads) |
a0d0e21e | 221 | |
19799a22 | 222 | Described in L<perlthrtut> and L<Thread>. |
a0d0e21e | 223 | |
19799a22 | 224 | =item * support for internationalization, localization, and Unicode |
a0d0e21e | 225 | |
19799a22 | 226 | Described in L<perllocale> and L<utf8>. |
a0d0e21e | 227 | |
19799a22 | 228 | =item * lexical scoping |
a0d0e21e | 229 | |
19799a22 | 230 | Described in L<perlsub>. |
a0d0e21e | 231 | |
19799a22 | 232 | =item * regular expression enhancements |
a0d0e21e | 233 | |
19799a22 | 234 | Described in L<perlre>, with additional examples in L<perlop>. |
a0d0e21e | 235 | |
14218588 | 236 | =item * enhanced debugger and interactive Perl environment, with integrated editor support |
a0d0e21e | 237 | |
19799a22 | 238 | Described in L<perldebug>. |
a0d0e21e | 239 | |
19799a22 | 240 | =item * POSIX 1003.1 compliant library |
5f05dabc | 241 | |
19799a22 | 242 | Described in L<POSIX>. |
5f05dabc | 243 | |
a0d0e21e LW |
244 | =back |
245 | ||
68dc0745 | 246 | Okay, that's I<definitely> enough hype. |
a0d0e21e | 247 | |
8e465e4e JH |
248 | =head1 AVAILABILITY |
249 | ||
14218588 | 250 | Perl is available for most operating systems, including virtually |
055fd3a9 GS |
251 | all Unix-like platforms. See L<perlport/"Supported Platforms"> |
252 | for a listing. | |
8bc4a6bb | 253 | |
a0d0e21e LW |
254 | =head1 ENVIRONMENT |
255 | ||
1e422769 | 256 | See L<perlrun>. |
a0d0e21e LW |
257 | |
258 | =head1 AUTHOR | |
259 | ||
19799a22 | 260 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. |
a0d0e21e | 261 | |
a99b1639 TP |
262 | If your Perl success stories and testimonials may be of help to others |
263 | who wish to advocate the use of Perl in their applications, | |
264 | or if you wish to simply express your gratitude to Larry and the | |
19799a22 | 265 | Perl developers, please write to perl-thanks@perl.org . |
a99b1639 | 266 | |
a0d0e21e LW |
267 | =head1 FILES |
268 | ||
5f05dabc | 269 | "@INC" locations of perl libraries |
a0d0e21e LW |
270 | |
271 | =head1 SEE ALSO | |
272 | ||
273 | a2p awk to perl translator | |
274 | s2p sed to perl translator | |
275 | ||
19799a22 | 276 | http://www.perl.com/ the Perl Home Page |
5a3e7812 | 277 | http://www.perl.com/CPAN the Comprehensive Perl Archive |
19799a22 | 278 | |
a0d0e21e LW |
279 | =head1 DIAGNOSTICS |
280 | ||
9f1b1f2d GS |
281 | The C<use warnings> pragma (and the B<-w> switch) produces some |
282 | lovely diagnostics. | |
a0d0e21e | 283 | |
5a964f20 TC |
284 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use |
285 | diagnostics> pragma automatically turns Perl's normally terse warnings | |
286 | and errors into these longer forms. | |
a0d0e21e LW |
287 | |
288 | Compilation errors will tell you the line number of the error, with an | |
289 | indication of the next token or token type that was to be examined. | |
14218588 | 290 | (In a script passed to Perl via B<-e> switches, each |
a0d0e21e LW |
291 | B<-e> is counted as one line.) |
292 | ||
293 | Setuid scripts have additional constraints that can produce error | |
294 | messages such as "Insecure dependency". See L<perlsec>. | |
295 | ||
296 | Did we mention that you should definitely consider using the B<-w> | |
297 | switch? | |
298 | ||
299 | =head1 BUGS | |
300 | ||
301 | The B<-w> switch is not mandatory. | |
302 | ||
303 | Perl is at the mercy of your machine's definitions of various | |
1b3f7d21 CS |
304 | operations such as type casting, atof(), and floating-point |
305 | output with sprintf(). | |
a0d0e21e | 306 | |
748a9306 | 307 | If your stdio requires a seek or eof between reads and writes on a |
a0d0e21e LW |
308 | particular stream, so does Perl. (This doesn't apply to sysread() |
309 | and syswrite().) | |
310 | ||
311 | While none of the built-in data types have any arbitrary size limits | |
312 | (apart from memory size), there are still a few arbitrary limits: a | |
a30ac152 GS |
313 | given variable name may not be longer than 251 characters. Line numbers |
314 | displayed by diagnostics are internally stored as short integers, | |
315 | so they are limited to a maximum of 65535 (higher numbers usually being | |
316 | affected by wraparound). | |
a0d0e21e | 317 | |
b0607b7a | 318 | You may mail your bug reports (be sure to include full configuration |
19799a22 GS |
319 | information as output by the myconfig program in the perl source |
320 | tree, or by C<perl -V>) to perlbug@perl.com . If you've succeeded | |
055fd3a9 | 321 | in compiling perl, the B<perlbug> script in the F<utils/> subdirectory |
19799a22 | 322 | can be used to help mail in a bug report. |
4633a7c4 | 323 | |
a0d0e21e LW |
324 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but |
325 | don't tell anyone I said that. | |
326 | ||
327 | =head1 NOTES | |
328 | ||
329 | The Perl motto is "There's more than one way to do it." Divining | |
330 | how many more is left as an exercise to the reader. | |
331 | ||
4633a7c4 | 332 | The three principal virtues of a programmer are Laziness, |
a0d0e21e | 333 | Impatience, and Hubris. See the Camel Book for why. |
16d20bd9 | 334 |