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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>] ]>
5a7ebd3d 16 S<[ B<-eE> 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
c2e66d9e 93 perlthrtut Perl threads tutorial
41630250 94 perlothrtut Old Perl threads tutorial
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95
96 perlport Perl portability guide
d396a558 97 perllocale Perl locale support
07fcf8ff 98 perluniintro Perl Unicode introduction
41630250 99 perlunicode Perl Unicode support
3426ea3d 100 perlunifaq Perl Unicode FAQ
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
108003db 130 perlreapi Perl regular expression plugin interface
b23a565d 131 perlreguts Perl regular expression engine internals
fd7b6849 132
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133 perlapi Perl API listing (autogenerated)
134 perlintern Perl internal functions (autogenerated)
dc5c060f 135 perliol C API for Perl's implementation of IO in Layers
4755096e 136 perlapio Perl internal IO abstraction interface
fd7b6849 137
e8cd7eae 138 perlhack Perl hackers guide
00f54a07 139 perlrepository Perl source repository
4755096e 140
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141=head2 Miscellaneous
142
143 perlbook Perl book information
cbd87e7e 144 perlcommunity Perl community information
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145 perltodo Perl things to do
146
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147 perldoc Look up Perl documentation in Pod format
148
fb9cefb4 149 perlhist Perl history records
4755096e 150 perldelta Perl changes since previous version
7120b314 151 perl5100delta Perl changes in version 5.10.0
cf6c151c 152 perl595delta Perl changes in version 5.9.5
f6eae373 153 perl594delta Perl changes in version 5.9.4
6c7deadb 154 perl593delta Perl changes in version 5.9.3
496c75d0 155 perl592delta Perl changes in version 5.9.2
e0eb806d 156 perl591delta Perl changes in version 5.9.1
1400179b 157 perl590delta Perl changes in version 5.9.0
c11a53c6 158 perl588delta Perl changes in version 5.8.8
315ba985 159 perl587delta Perl changes in version 5.8.7
e4bb216d 160 perl586delta Perl changes in version 5.8.6
07e9b5fe 161 perl585delta Perl changes in version 5.8.5
5f15c94e 162 perl584delta Perl changes in version 5.8.4
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163 perl583delta Perl changes in version 5.8.3
164 perl582delta Perl changes in version 5.8.2
b6235c4f 165 perl581delta Perl changes in version 5.8.1
2e038148 166 perl58delta Perl changes in version 5.8.0
77b096b5 167 perl573delta Perl changes in version 5.7.3
245d750e 168 perl572delta Perl changes in version 5.7.2
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169 perl571delta Perl changes in version 5.7.1
170 perl570delta Perl changes in version 5.7.0
493a87da 171 perl561delta Perl changes in version 5.6.1
41630250 172 perl56delta Perl changes in version 5.6
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173 perl5005delta Perl changes in version 5.005
174 perl5004delta Perl changes in version 5.004
d516a115 175
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176 perlartistic Perl Artistic License
177 perlgpl GNU General Public License
178
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179=head2 Language-Specific
180
181 perlcn Perl for Simplified Chinese (in EUC-CN)
182 perljp Perl for Japanese (in EUC-JP)
183 perlko Perl for Korean (in EUC-KR)
184 perltw Perl for Traditional Chinese (in Big5)
185
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186=head2 Platform-Specific
187
37d4d706 188 perlaix Perl notes for AIX
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189 perlamiga Perl notes for AmigaOS
190 perlapollo Perl notes for Apollo DomainOS
191 perlbeos Perl notes for BeOS
dc5c060f 192 perlbs2000 Perl notes for POSIX-BC BS2000
a1f19229 193 perlce Perl notes for WinCE
49877630 194 perlcygwin Perl notes for Cygwin
245d750e 195 perldgux Perl notes for DG/UX
49877630 196 perldos Perl notes for DOS
9a997319 197 perlepoc Perl notes for EPOC
41630250 198 perlfreebsd Perl notes for FreeBSD
f6706af3 199 perlhaiku Perl notes for Haiku
49877630 200 perlhpux Perl notes for HP-UX
a83b6f46 201 perlhurd Perl notes for Hurd
469e7be4 202 perlirix Perl notes for Irix
991e8403 203 perllinux Perl notes for Linux
41630250 204 perlmachten Perl notes for Power MachTen
26d9b02f 205 perlmacos Perl notes for Mac OS (Classic)
0d53b15f 206 perlmacosx Perl notes for Mac OS X
a83b6f46 207 perlmint Perl notes for MiNT
ab648d5e 208 perlmpeix Perl notes for MPE/iX
41630250 209 perlnetware Perl notes for NetWare
b0846812 210 perlopenbsd Perl notes for OpenBSD
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211 perlos2 Perl notes for OS/2
212 perlos390 Perl notes for OS/390
522b859a 213 perlos400 Perl notes for OS/400
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214 perlplan9 Perl notes for Plan 9
215 perlqnx Perl notes for QNX
2f08ed66 216 perlriscos Perl notes for RISC OS
d420ca49 217 perlsolaris Perl notes for Solaris
27da23d5 218 perlsymbian Perl notes for Symbian
772ff3b9 219 perltru64 Perl notes for Tru64
41630250 220 perluts Perl notes for UTS
cbe1151c 221 perlvmesa Perl notes for VM/ESA
49877630 222 perlvms Perl notes for VMS
9a997319 223 perlvos Perl notes for Stratus VOS
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224 perlwin32 Perl notes for Windows
225
a0d0e21e 226
19799a22 227By default, the manpages listed above are installed in the
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228F</usr/local/man/> directory.
229
230Extensive additional documentation for Perl modules is available. The
231default configuration for perl will place this additional documentation
232in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
233subdirectory of the Perl library directory). Some of this additional
234documentation is distributed standard with Perl, but you'll also find
235documentation for third-party modules there.
236
237You should be able to view Perl's documentation with your man(1)
238program by including the proper directories in the appropriate start-up
239files, or in the MANPATH environment variable. To find out where the
240configuration has installed the manpages, type:
16d20bd9 241
760ac839 242 perl -V:man.dir
16d20bd9 243
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244If the directories have a common stem, such as F</usr/local/man/man1>
245and F</usr/local/man/man3>, you need only to add that stem
246(F</usr/local/man>) to your man(1) configuration files or your MANPATH
247environment variable. If they do not share a stem, you'll have to add
248both stems.
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249
250If that doesn't work for some reason, you can still use the
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251supplied F<perldoc> script to view module information. You might
252also look into getting a replacement man program.
16d20bd9 253
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254If something strange has gone wrong with your program and you're not
255sure where you should look for help, try the B<-w> switch first. It
256will often point out exactly where the trouble is.
257
258=head1 DESCRIPTION
259
5f05dabc 260Perl is a language optimized for scanning arbitrary
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261text files, extracting information from those text files, and printing
262reports based on that information. It's also a good language for many
263system management tasks. The language is intended to be practical
264(easy to use, efficient, complete) rather than beautiful (tiny,
94d58c47 265elegant, minimal).
266
aa689395 267Perl combines (in the author's opinion, anyway) some of the best
268features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
269those languages should have little difficulty with it. (Language
270historians will also note some vestiges of B<csh>, Pascal, and even
14218588 271BASIC-PLUS.) Expression syntax corresponds closely to C
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272expression syntax. Unlike most Unix utilities, Perl does not
273arbitrarily limit the size of your data--if you've got the memory,
aa689395 274Perl can slurp in your whole file as a single string. Recursion is of
0f31cffe 275unlimited depth. And the tables used by hashes (sometimes called
aa689395 276"associative arrays") grow as necessary to prevent degraded
0f31cffe 277performance. Perl can use sophisticated pattern matching techniques to
14218588 278scan large amounts of data quickly. Although optimized for
aa689395 279scanning text, Perl can also deal with binary data, and can make dbm
280files look like hashes. Setuid Perl scripts are safer than C programs
14218588 281through a dataflow tracing mechanism that prevents many stupid
aa689395 282security holes.
283
284If you have a problem that would ordinarily use B<sed> or B<awk> or
285B<sh>, but it exceeds their capabilities or must run a little faster,
286and you don't want to write the silly thing in C, then Perl may be for
287you. There are also translators to turn your B<sed> and B<awk>
288scripts into Perl scripts.
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289
290But wait, there's more...
291
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292Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
293rewrite that provides the following additional benefits:
a0d0e21e 294
13a2d996 295=over 4
a0d0e21e 296
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297=item *
298
299modularity and reusability using innumerable modules
a0d0e21e 300
19799a22 301Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
a0d0e21e 302
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303=item *
304
305embeddable and extensible
a0d0e21e 306
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307Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
308L<perlguts>, and L<xsubpp>.
a0d0e21e 309
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310=item *
311
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312roll-your-own magic variables (including multiple simultaneous DBM
313implementations)
a0d0e21e 314
19799a22 315Described in L<perltie> and L<AnyDBM_File>.
a0d0e21e 316
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317=item *
318
319subroutines can now be overridden, autoloaded, and prototyped
a0d0e21e 320
19799a22 321Described in L<perlsub>.
a0d0e21e 322
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323=item *
324
325arbitrarily nested data structures and anonymous functions
a0d0e21e 326
19799a22 327Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
a0d0e21e 328
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329=item *
330
331object-oriented programming
a0d0e21e 332
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333Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
334and L<perlbot>.
a0d0e21e 335
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336=item *
337
551e1d92 338support for light-weight processes (threads)
a0d0e21e 339
63de3cb2 340Described in L<perlthrtut> and L<threads>.
a0d0e21e 341
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342=item *
343
63de3cb2 344support for Unicode, internationalization, and localization
a0d0e21e 345
63de3cb2 346Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
a0d0e21e 347
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348=item *
349
350lexical scoping
a0d0e21e 351
19799a22 352Described in L<perlsub>.
a0d0e21e 353
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354=item *
355
356regular expression enhancements
a0d0e21e 357
19799a22 358Described in L<perlre>, with additional examples in L<perlop>.
a0d0e21e 359
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360=item *
361
362enhanced debugger and interactive Perl environment,
363with integrated editor support
a0d0e21e 364
f6b3c421 365Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
a0d0e21e 366
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367=item *
368
369POSIX 1003.1 compliant library
5f05dabc 370
19799a22 371Described in L<POSIX>.
5f05dabc 372
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373=back
374
68dc0745 375Okay, that's I<definitely> enough hype.
a0d0e21e 376
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377=head1 AVAILABILITY
378
14218588 379Perl is available for most operating systems, including virtually
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380all Unix-like platforms. See L<perlport/"Supported Platforms">
381for a listing.
8bc4a6bb 382
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383=head1 ENVIRONMENT
384
1e422769 385See L<perlrun>.
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386
387=head1 AUTHOR
388
19799a22 389Larry Wall <larry@wall.org>, with the help of oodles of other folks.
a0d0e21e 390
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391If your Perl success stories and testimonials may be of help to others
392who wish to advocate the use of Perl in their applications,
393or if you wish to simply express your gratitude to Larry and the
19799a22 394Perl developers, please write to perl-thanks@perl.org .
a99b1639 395
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396=head1 FILES
397
5f05dabc 398 "@INC" locations of perl libraries
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399
400=head1 SEE ALSO
401
402 a2p awk to perl translator
403 s2p sed to perl translator
404
c5f69108 405 http://www.perl.org/ the Perl homepage
da9e6348 406 http://www.perl.com/ Perl articles (O'Reilly)
f6b3c421 407 http://www.cpan.org/ the Comprehensive Perl Archive
c5f69108 408 http://www.pm.org/ the Perl Mongers
19799a22 409
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410=head1 DIAGNOSTICS
411
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412The C<use warnings> pragma (and the B<-w> switch) produces some
413lovely diagnostics.
a0d0e21e 414
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415See L<perldiag> for explanations of all Perl's diagnostics. The C<use
416diagnostics> pragma automatically turns Perl's normally terse warnings
417and errors into these longer forms.
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418
419Compilation errors will tell you the line number of the error, with an
420indication of the next token or token type that was to be examined.
14218588 421(In a script passed to Perl via B<-e> switches, each
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422B<-e> is counted as one line.)
423
424Setuid scripts have additional constraints that can produce error
425messages such as "Insecure dependency". See L<perlsec>.
426
427Did we mention that you should definitely consider using the B<-w>
428switch?
429
430=head1 BUGS
431
432The B<-w> switch is not mandatory.
433
434Perl is at the mercy of your machine's definitions of various
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435operations such as type casting, atof(), and floating-point
436output with sprintf().
a0d0e21e 437
748a9306 438If your stdio requires a seek or eof between reads and writes on a
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439particular stream, so does Perl. (This doesn't apply to sysread()
440and syswrite().)
441
442While none of the built-in data types have any arbitrary size limits
443(apart from memory size), there are still a few arbitrary limits: a
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444given variable name may not be longer than 251 characters. Line numbers
445displayed by diagnostics are internally stored as short integers,
446so they are limited to a maximum of 65535 (higher numbers usually being
447affected by wraparound).
a0d0e21e 448
b0607b7a 449You may mail your bug reports (be sure to include full configuration
19799a22 450information as output by the myconfig program in the perl source
7f2de2d2 451tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
055fd3a9 452in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
19799a22 453can be used to help mail in a bug report.
4633a7c4 454
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455Perl actually stands for Pathologically Eclectic Rubbish Lister, but
456don't tell anyone I said that.
457
458=head1 NOTES
459
460The Perl motto is "There's more than one way to do it." Divining
461how many more is left as an exercise to the reader.
462
4633a7c4 463The three principal virtues of a programmer are Laziness,
a0d0e21e 464Impatience, and Hubris. See the Camel Book for why.
16d20bd9 465