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