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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<-sTtuUWX> ]>
8 S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
9 S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
10 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
11 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]>
df451b2a 12 S<[ B<-C [I<number/list>] >]>
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13 S<[ B<-S> ]>
14 S<[ B<-x>[I<dir>] ]>
15 S<[ B<-i>[I<extension>] ]>
eb1dd64e 16 S<[ [B<-e>|B<-E>] I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
c07a80fd 17
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18If you're new to Perl, you should start with L<perlintro>, which is a
19general intro for beginners and provides some background to help you
20navigate the rest of Perl's extensive documentation.
21
22For ease of access, the Perl manual has been split up into several sections.
a0d0e21e 23
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24=head2 Overview
25
fb9cefb4 26 perl Perl overview (this section)
10151d09 27 perlintro Perl introduction for beginners
fb9cefb4 28 perltoc Perl documentation table of contents
760ac839 29
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30=head2 Tutorials
31
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32 perlreftut Perl references short introduction
33 perldsc Perl data structures intro
34 perllol Perl data structures: arrays of arrays
7a2320f0 35
41630250 36 perlrequick Perl regular expressions quick start
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37 perlretut Perl regular expressions tutorial
38
39 perlboot Perl OO tutorial for beginners
40 perltoot Perl OO tutorial, part 1
41 perltooc Perl OO tutorial, part 2
42 perlbot Perl OO tricks and examples
43
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44 perlperf Perl Performance and Optimization Techniques
45
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46 perlstyle Perl style guide
47
41630250 48 perlcheat Perl cheat sheet
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49 perltrap Perl traps for the unwary
50 perldebtut Perl debugging tutorial
51
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52 perlfaq Perl frequently asked questions
53 perlfaq1 General Questions About Perl
54 perlfaq2 Obtaining and Learning about Perl
55 perlfaq3 Programming Tools
56 perlfaq4 Data Manipulation
57 perlfaq5 Files and Formats
58 perlfaq6 Regexes
59 perlfaq7 Perl Language Issues
60 perlfaq8 System Interaction
61 perlfaq9 Networking
0f542199 62
fd7b6849 63=head2 Reference Manual
413510b3 64
fb9cefb4 65 perlsyn Perl syntax
4755096e 66 perldata Perl data structures
fb9cefb4 67 perlop Perl operators and precedence
c2e66d9e 68 perlsub Perl subroutines
fd7b6849 69 perlfunc Perl built-in functions
413510b3 70 perlopentut Perl open() tutorial
41630250 71 perlpacktut Perl pack() and unpack() tutorial
c2e66d9e 72 perlpod Perl plain old documentation
41630250 73 perlpodspec Perl plain old documentation format specification
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74 perlrun Perl execution and options
75 perldiag Perl diagnostic messages
41630250 76 perllexwarn Perl warnings and their control
4755096e 77 perldebug Perl debugging
fb9cefb4 78 perlvar Perl predefined variables
4755096e 79 perlre Perl regular expressions, the rest of the story
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80 perlrebackslash Perl regular expression backslash sequences
81 perlrecharclass Perl regular expression character classes
30487ceb 82 perlreref Perl regular expressions quick reference
d396a558 83 perlref Perl references, the rest of the story
fb9cefb4 84 perlform Perl formats
d396a558 85 perlobj Perl objects
d396a558 86 perltie Perl objects hidden behind simple variables
fd7b6849 87 perldbmfilter Perl DBM filters
760ac839 88
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89 perlipc Perl interprocess communication
90 perlfork Perl fork() information
91 perlnumber Perl number semantics
53d7eaa8 92
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93 perlthrtut Perl threads tutorial
94
95 perlport Perl portability guide
d396a558 96 perllocale Perl locale support
07fcf8ff 97 perluniintro Perl Unicode introduction
41630250 98 perlunicode Perl Unicode support
3426ea3d 99 perlunifaq Perl Unicode FAQ
e06a4ec4 100 perluniprops Complete index of Unicode Version 5.1.0 properties
aadaa455 101 perlunitut Perl Unicode tutorial
d396a558 102 perlebcdic Considerations for running Perl on EBCDIC platforms
c2e66d9e 103
d396a558 104 perlsec Perl security
4755096e 105
c2e66d9e 106 perlmod Perl modules: how they work
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107 perlmodlib Perl modules: how to write and use
108 perlmodstyle Perl modules: how to write modules with style
fd7b6849 109 perlmodinstall Perl modules: how to install from CPAN
c2e66d9e 110 perlnewmod Perl modules: preparing a new module for distribution
a550ee30 111 perlpragma Perl modules: writing a user pragma
760ac839 112
fd7b6849 113 perlutil utilities packaged with the Perl distribution
760ac839 114
41630250 115 perlcompile Perl compiler suite intro
760ac839 116
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117 perlfilter Perl source filters
118
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119 perlglossary Perl Glossary
120
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121=head2 Internals and C Language Interface
122
fb9cefb4 123 perlembed Perl ways to embed perl in your C or C++ application
41630250 124 perldebguts Perl debugging guts and tips
fb9cefb4 125 perlxstut Perl XS tutorial
4755096e 126 perlxs Perl XS application programming interface
f40a6c71 127 perlclib Internal replacements for standard C library functions
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128 perlguts Perl internal functions for those doing extensions
129 perlcall Perl calling conventions from C
15932acc 130 perlmroapi Perl method resolution plugin interface
108003db 131 perlreapi Perl regular expression plugin interface
b23a565d 132 perlreguts Perl regular expression engine internals
fd7b6849 133
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134 perlapi Perl API listing (autogenerated)
135 perlintern Perl internal functions (autogenerated)
dc5c060f 136 perliol C API for Perl's implementation of IO in Layers
4755096e 137 perlapio Perl internal IO abstraction interface
fd7b6849 138
e8cd7eae 139 perlhack Perl hackers guide
cb8a010e 140 perlpolicy Perl development policies
00f54a07 141 perlrepository Perl source repository
4755096e 142
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143=head2 Miscellaneous
144
145 perlbook Perl book information
cbd87e7e 146 perlcommunity Perl community information
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147 perltodo Perl things to do
148
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149 perldoc Look up Perl documentation in Pod format
150
fb9cefb4 151 perlhist Perl history records
2bc3a088 152 perl5120delta Perl changes in version 5.12.0
4755096e 153 perldelta Perl changes since previous version
3be84f1f 154 perl5114delta Perl changes in version 5.11.4
e06a4ec4 155 perl5113delta Perl changes in version 5.11.3
2e8102e6 156 perl5112delta Perl changes in version 5.11.2
d5114285 157 perl5111delta Perl changes in version 5.11.1
11545435 158 perl5110delta Perl changes in version 5.11.0
7cdf958d 159 perl5101delta Perl changes in version 5.10.1
7120b314 160 perl5100delta Perl changes in version 5.10.0
cf6c151c 161 perl595delta Perl changes in version 5.9.5
f6eae373 162 perl594delta Perl changes in version 5.9.4
6c7deadb 163 perl593delta Perl changes in version 5.9.3
496c75d0 164 perl592delta Perl changes in version 5.9.2
e0eb806d 165 perl591delta Perl changes in version 5.9.1
1400179b 166 perl590delta Perl changes in version 5.9.0
fc5be808 167 perl589delta Perl changes in version 5.8.9
c11a53c6 168 perl588delta Perl changes in version 5.8.8
315ba985 169 perl587delta Perl changes in version 5.8.7
e4bb216d 170 perl586delta Perl changes in version 5.8.6
07e9b5fe 171 perl585delta Perl changes in version 5.8.5
5f15c94e 172 perl584delta Perl changes in version 5.8.4
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173 perl583delta Perl changes in version 5.8.3
174 perl582delta Perl changes in version 5.8.2
b6235c4f 175 perl581delta Perl changes in version 5.8.1
2e038148 176 perl58delta Perl changes in version 5.8.0
77b096b5 177 perl573delta Perl changes in version 5.7.3
245d750e 178 perl572delta Perl changes in version 5.7.2
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179 perl571delta Perl changes in version 5.7.1
180 perl570delta Perl changes in version 5.7.0
493a87da 181 perl561delta Perl changes in version 5.6.1
41630250 182 perl56delta Perl changes in version 5.6
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183 perl5005delta Perl changes in version 5.005
184 perl5004delta Perl changes in version 5.004
d516a115 185
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186 perlartistic Perl Artistic License
187 perlgpl GNU General Public License
188
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189=head2 Language-Specific
190
191 perlcn Perl for Simplified Chinese (in EUC-CN)
192 perljp Perl for Japanese (in EUC-JP)
193 perlko Perl for Korean (in EUC-KR)
194 perltw Perl for Traditional Chinese (in Big5)
195
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196=head2 Platform-Specific
197
37d4d706 198 perlaix Perl notes for AIX
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199 perlamiga Perl notes for AmigaOS
200 perlapollo Perl notes for Apollo DomainOS
201 perlbeos Perl notes for BeOS
dc5c060f 202 perlbs2000 Perl notes for POSIX-BC BS2000
a1f19229 203 perlce Perl notes for WinCE
49877630 204 perlcygwin Perl notes for Cygwin
245d750e 205 perldgux Perl notes for DG/UX
49877630 206 perldos Perl notes for DOS
9a997319 207 perlepoc Perl notes for EPOC
41630250 208 perlfreebsd Perl notes for FreeBSD
f6706af3 209 perlhaiku Perl notes for Haiku
49877630 210 perlhpux Perl notes for HP-UX
a83b6f46 211 perlhurd Perl notes for Hurd
469e7be4 212 perlirix Perl notes for Irix
991e8403 213 perllinux Perl notes for Linux
26d9b02f 214 perlmacos Perl notes for Mac OS (Classic)
0d53b15f 215 perlmacosx Perl notes for Mac OS X
ab648d5e 216 perlmpeix Perl notes for MPE/iX
41630250 217 perlnetware Perl notes for NetWare
b0846812 218 perlopenbsd Perl notes for OpenBSD
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219 perlos2 Perl notes for OS/2
220 perlos390 Perl notes for OS/390
522b859a 221 perlos400 Perl notes for OS/400
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222 perlplan9 Perl notes for Plan 9
223 perlqnx Perl notes for QNX
2f08ed66 224 perlriscos Perl notes for RISC OS
d420ca49 225 perlsolaris Perl notes for Solaris
27da23d5 226 perlsymbian Perl notes for Symbian
772ff3b9 227 perltru64 Perl notes for Tru64
41630250 228 perluts Perl notes for UTS
cbe1151c 229 perlvmesa Perl notes for VM/ESA
49877630 230 perlvms Perl notes for VMS
9a997319 231 perlvos Perl notes for Stratus VOS
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232 perlwin32 Perl notes for Windows
233
a0d0e21e 234
19799a22 235By default, the manpages listed above are installed in the
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236F</usr/local/man/> directory.
237
238Extensive additional documentation for Perl modules is available. The
239default configuration for perl will place this additional documentation
240in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
241subdirectory of the Perl library directory). Some of this additional
242documentation is distributed standard with Perl, but you'll also find
243documentation for third-party modules there.
244
245You should be able to view Perl's documentation with your man(1)
246program by including the proper directories in the appropriate start-up
247files, or in the MANPATH environment variable. To find out where the
248configuration has installed the manpages, type:
16d20bd9 249
760ac839 250 perl -V:man.dir
16d20bd9 251
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252If the directories have a common stem, such as F</usr/local/man/man1>
253and F</usr/local/man/man3>, you need only to add that stem
254(F</usr/local/man>) to your man(1) configuration files or your MANPATH
255environment variable. If they do not share a stem, you'll have to add
256both stems.
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257
258If that doesn't work for some reason, you can still use the
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259supplied F<perldoc> script to view module information. You might
260also look into getting a replacement man program.
16d20bd9 261
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262If something strange has gone wrong with your program and you're not
263sure where you should look for help, try the B<-w> switch first. It
264will often point out exactly where the trouble is.
265
266=head1 DESCRIPTION
267
5f05dabc 268Perl is a language optimized for scanning arbitrary
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269text files, extracting information from those text files, and printing
270reports based on that information. It's also a good language for many
271system management tasks. The language is intended to be practical
272(easy to use, efficient, complete) rather than beautiful (tiny,
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273elegant, minimal).
274
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275Perl combines (in the author's opinion, anyway) some of the best
276features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
277those languages should have little difficulty with it. (Language
278historians will also note some vestiges of B<csh>, Pascal, and even
14218588 279BASIC-PLUS.) Expression syntax corresponds closely to C
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280expression syntax. Unlike most Unix utilities, Perl does not
281arbitrarily limit the size of your data--if you've got the memory,
aa689395 282Perl can slurp in your whole file as a single string. Recursion is of
0f31cffe 283unlimited depth. And the tables used by hashes (sometimes called
aa689395 284"associative arrays") grow as necessary to prevent degraded
0f31cffe 285performance. Perl can use sophisticated pattern matching techniques to
14218588 286scan large amounts of data quickly. Although optimized for
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287scanning text, Perl can also deal with binary data, and can make dbm
288files look like hashes. Setuid Perl scripts are safer than C programs
14218588 289through a dataflow tracing mechanism that prevents many stupid
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290security holes.
291
292If you have a problem that would ordinarily use B<sed> or B<awk> or
293B<sh>, but it exceeds their capabilities or must run a little faster,
294and you don't want to write the silly thing in C, then Perl may be for
295you. There are also translators to turn your B<sed> and B<awk>
296scripts into Perl scripts.
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297
298But wait, there's more...
299
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300Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
301rewrite that provides the following additional benefits:
a0d0e21e 302
13a2d996 303=over 4
a0d0e21e 304
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305=item *
306
307modularity and reusability using innumerable modules
a0d0e21e 308
19799a22 309Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
a0d0e21e 310
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311=item *
312
313embeddable and extensible
a0d0e21e 314
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315Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
316L<perlguts>, and L<xsubpp>.
a0d0e21e 317
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318=item *
319
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320roll-your-own magic variables (including multiple simultaneous DBM
321implementations)
a0d0e21e 322
19799a22 323Described in L<perltie> and L<AnyDBM_File>.
a0d0e21e 324
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325=item *
326
327subroutines can now be overridden, autoloaded, and prototyped
a0d0e21e 328
19799a22 329Described in L<perlsub>.
a0d0e21e 330
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331=item *
332
333arbitrarily nested data structures and anonymous functions
a0d0e21e 334
19799a22 335Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
a0d0e21e 336
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337=item *
338
339object-oriented programming
a0d0e21e 340
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341Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
342and L<perlbot>.
a0d0e21e 343
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344=item *
345
551e1d92 346support for light-weight processes (threads)
a0d0e21e 347
63de3cb2 348Described in L<perlthrtut> and L<threads>.
a0d0e21e 349
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350=item *
351
63de3cb2 352support for Unicode, internationalization, and localization
a0d0e21e 353
63de3cb2 354Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
a0d0e21e 355
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356=item *
357
358lexical scoping
a0d0e21e 359
19799a22 360Described in L<perlsub>.
a0d0e21e 361
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362=item *
363
364regular expression enhancements
a0d0e21e 365
19799a22 366Described in L<perlre>, with additional examples in L<perlop>.
a0d0e21e 367
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368=item *
369
370enhanced debugger and interactive Perl environment,
371with integrated editor support
a0d0e21e 372
f6b3c421 373Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
a0d0e21e 374
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375=item *
376
377POSIX 1003.1 compliant library
5f05dabc 378
19799a22 379Described in L<POSIX>.
5f05dabc 380
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381=back
382
68dc0745 383Okay, that's I<definitely> enough hype.
a0d0e21e 384
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385=head1 AVAILABILITY
386
14218588 387Perl is available for most operating systems, including virtually
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388all Unix-like platforms. See L<perlport/"Supported Platforms">
389for a listing.
8bc4a6bb 390
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391=head1 ENVIRONMENT
392
1e422769 393See L<perlrun>.
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394
395=head1 AUTHOR
396
19799a22 397Larry Wall <larry@wall.org>, with the help of oodles of other folks.
a0d0e21e 398
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399If your Perl success stories and testimonials may be of help to others
400who wish to advocate the use of Perl in their applications,
401or if you wish to simply express your gratitude to Larry and the
19799a22 402Perl developers, please write to perl-thanks@perl.org .
a99b1639 403
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404=head1 FILES
405
5f05dabc 406 "@INC" locations of perl libraries
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407
408=head1 SEE ALSO
409
410 a2p awk to perl translator
411 s2p sed to perl translator
412
c5f69108 413 http://www.perl.org/ the Perl homepage
da9e6348 414 http://www.perl.com/ Perl articles (O'Reilly)
f6b3c421 415 http://www.cpan.org/ the Comprehensive Perl Archive
c5f69108 416 http://www.pm.org/ the Perl Mongers
19799a22 417
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418=head1 DIAGNOSTICS
419
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420The C<use warnings> pragma (and the B<-w> switch) produces some
421lovely diagnostics.
a0d0e21e 422
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423See L<perldiag> for explanations of all Perl's diagnostics. The C<use
424diagnostics> pragma automatically turns Perl's normally terse warnings
425and errors into these longer forms.
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426
427Compilation errors will tell you the line number of the error, with an
428indication of the next token or token type that was to be examined.
14218588 429(In a script passed to Perl via B<-e> switches, each
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430B<-e> is counted as one line.)
431
432Setuid scripts have additional constraints that can produce error
433messages such as "Insecure dependency". See L<perlsec>.
434
435Did we mention that you should definitely consider using the B<-w>
436switch?
437
438=head1 BUGS
439
440The B<-w> switch is not mandatory.
441
442Perl is at the mercy of your machine's definitions of various
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443operations such as type casting, atof(), and floating-point
444output with sprintf().
a0d0e21e 445
748a9306 446If your stdio requires a seek or eof between reads and writes on a
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447particular stream, so does Perl. (This doesn't apply to sysread()
448and syswrite().)
449
450While none of the built-in data types have any arbitrary size limits
451(apart from memory size), there are still a few arbitrary limits: a
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452given variable name may not be longer than 251 characters. Line numbers
453displayed by diagnostics are internally stored as short integers,
454so they are limited to a maximum of 65535 (higher numbers usually being
455affected by wraparound).
a0d0e21e 456
b0607b7a 457You may mail your bug reports (be sure to include full configuration
19799a22 458information as output by the myconfig program in the perl source
7f2de2d2 459tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
055fd3a9 460in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
19799a22 461can be used to help mail in a bug report.
4633a7c4 462
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463Perl actually stands for Pathologically Eclectic Rubbish Lister, but
464don't tell anyone I said that.
465
466=head1 NOTES
467
468The Perl motto is "There's more than one way to do it." Divining
469how many more is left as an exercise to the reader.
470
4633a7c4 471The three principal virtues of a programmer are Laziness,
a0d0e21e 472Impatience, and Hubris. See the Camel Book for why.
16d20bd9 473