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