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1=head1 NAME
2
095a5c3e 3perl - The Perl 5 language interpreter
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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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18For more information on these options, you can run C<perldoc perlrun>.
19
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20=head1 GETTING HELP
21
22The F<perldoc> program gives you access to all the documentation that comes
23with Perl. You can get more documentation, tutorials and community support
24online at L<http://www.perl.org/>.
25
26If you're new to Perl, you should start by running C<perldoc perlintro>,
27which is a general intro for beginners and provides some background to help
28you navigate the rest of Perl's extensive documentation. Run C<perldoc
29perldoc> to learn more things you can do with F<perldoc>.
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30
31For ease of access, the Perl manual has been split up into several sections.
a0d0e21e 32
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33=begin buildtoc
34
35# This section is parsed by Porting/pod_lib.pl for use by pod/buildtoc etc
36
37flag =g perluniprops perlmodlib perlapi perlintern
38flag =go perltoc
39flag =ro perlcn perljp perlko perltw
40flag = perlvms
41
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42path perlfaq.* cpan/perlfaq/lib/
43path perlglossary cpan/perlfaq/lib/
44path perlxs(?:tut|typemap)? dist/ExtUtils-ParseXS/lib/
cb1974ba 45path perldoc cpan/Pod-Perldoc/
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46
47aux a2p c2ph h2ph h2xs perlbug pl2pm pod2html pod2man s2p splain xsubpp
48
49=end buildtoc
50
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51=head2 Overview
52
fb9cefb4 53 perl Perl overview (this section)
10151d09 54 perlintro Perl introduction for beginners
b28fe7ca 55 perlrun Perl execution and options
fb9cefb4 56 perltoc Perl documentation table of contents
760ac839 57
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58=head2 Tutorials
59
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60 perlreftut Perl references short introduction
61 perldsc Perl data structures intro
62 perllol Perl data structures: arrays of arrays
7a2320f0 63
41630250 64 perlrequick Perl regular expressions quick start
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65 perlretut Perl regular expressions tutorial
66
82e1c0d9 67 perlootut Perl OO tutorial for beginners
7a2320f0 68
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69 perlperf Perl Performance and Optimization Techniques
70
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71 perlstyle Perl style guide
72
41630250 73 perlcheat Perl cheat sheet
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74 perltrap Perl traps for the unwary
75 perldebtut Perl debugging tutorial
76
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77 perlfaq Perl frequently asked questions
78 perlfaq1 General Questions About Perl
79 perlfaq2 Obtaining and Learning about Perl
80 perlfaq3 Programming Tools
81 perlfaq4 Data Manipulation
82 perlfaq5 Files and Formats
83 perlfaq6 Regexes
84 perlfaq7 Perl Language Issues
85 perlfaq8 System Interaction
86 perlfaq9 Networking
0f542199 87
fd7b6849 88=head2 Reference Manual
413510b3 89
fb9cefb4 90 perlsyn Perl syntax
4755096e 91 perldata Perl data structures
fb9cefb4 92 perlop Perl operators and precedence
c2e66d9e 93 perlsub Perl subroutines
fd7b6849 94 perlfunc Perl built-in functions
413510b3 95 perlopentut Perl open() tutorial
41630250 96 perlpacktut Perl pack() and unpack() tutorial
c2e66d9e 97 perlpod Perl plain old documentation
41630250 98 perlpodspec Perl plain old documentation format specification
f4d47668 99 perlpodstyle Perl POD style guide
c2e66d9e 100 perldiag Perl diagnostic messages
41630250 101 perllexwarn Perl warnings and their control
4755096e 102 perldebug Perl debugging
fb9cefb4 103 perlvar Perl predefined variables
4755096e 104 perlre Perl regular expressions, the rest of the story
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105 perlrebackslash Perl regular expression backslash sequences
106 perlrecharclass Perl regular expression character classes
30487ceb 107 perlreref Perl regular expressions quick reference
d396a558 108 perlref Perl references, the rest of the story
fb9cefb4 109 perlform Perl formats
d396a558 110 perlobj Perl objects
d396a558 111 perltie Perl objects hidden behind simple variables
fd7b6849 112 perldbmfilter Perl DBM filters
760ac839 113
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114 perlipc Perl interprocess communication
115 perlfork Perl fork() information
116 perlnumber Perl number semantics
53d7eaa8 117
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118 perlthrtut Perl threads tutorial
119
120 perlport Perl portability guide
d396a558 121 perllocale Perl locale support
07fcf8ff 122 perluniintro Perl Unicode introduction
41630250 123 perlunicode Perl Unicode support
5dd47fd4 124 perlunicook Perl Unicode cookbook
3426ea3d 125 perlunifaq Perl Unicode FAQ
0cb5a9a8 126 perluniprops Index of Unicode properties in Perl
aadaa455 127 perlunitut Perl Unicode tutorial
d396a558 128 perlebcdic Considerations for running Perl on EBCDIC platforms
c2e66d9e 129
d396a558 130 perlsec Perl security
4755096e 131
c2e66d9e 132 perlmod Perl modules: how they work
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133 perlmodlib Perl modules: how to write and use
134 perlmodstyle Perl modules: how to write modules with style
fd7b6849 135 perlmodinstall Perl modules: how to install from CPAN
c2e66d9e 136 perlnewmod Perl modules: preparing a new module for distribution
a550ee30 137 perlpragma Perl modules: writing a user pragma
760ac839 138
fd7b6849 139 perlutil utilities packaged with the Perl distribution
760ac839 140
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141 perlfilter Perl source filters
142
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143 perldtrace Perl's support for DTrace
144
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145 perlglossary Perl Glossary
146
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147=head2 Internals and C Language Interface
148
fb9cefb4 149 perlembed Perl ways to embed perl in your C or C++ application
41630250 150 perldebguts Perl debugging guts and tips
fb9cefb4 151 perlxstut Perl XS tutorial
4755096e 152 perlxs Perl XS application programming interface
0eb29def 153 perlxstypemap Perl XS C/Perl type conversion tools
f40a6c71 154 perlclib Internal replacements for standard C library functions
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155 perlguts Perl internal functions for those doing extensions
156 perlcall Perl calling conventions from C
15932acc 157 perlmroapi Perl method resolution plugin interface
108003db 158 perlreapi Perl regular expression plugin interface
b23a565d 159 perlreguts Perl regular expression engine internals
fd7b6849 160
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161 perlapi Perl API listing (autogenerated)
162 perlintern Perl internal functions (autogenerated)
dc5c060f 163 perliol C API for Perl's implementation of IO in Layers
4755096e 164 perlapio Perl internal IO abstraction interface
fd7b6849 165
e8cd7eae 166 perlhack Perl hackers guide
04c692a8 167 perlsource Guide to the Perl source tree
1c2e8cca 168 perlinterp Overview of the Perl interpreter source and how it works
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169 perlhacktut Walk through the creation of a simple C code patch
170 perlhacktips Tips for Perl core C code hacking
cb8a010e 171 perlpolicy Perl development policies
04c692a8 172 perlgit Using git with the Perl repository
4755096e 173
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174=head2 Miscellaneous
175
176 perlbook Perl book information
cbd87e7e 177 perlcommunity Perl community information
fd7b6849 178
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179 perldoc Look up Perl documentation in Pod format
180
fb9cefb4 181 perlhist Perl history records
bdfb6cc8 182 perldelta Perl changes since previous version
2ff1ebfe 183 perl5218delta Perl changes in version 5.21.8
b5d4d3b9 184 perl5217delta Perl changes in version 5.21.7
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185 perl5216delta Perl changes in version 5.21.6
186 perl5215delta Perl changes in version 5.21.5
187 perl5214delta Perl changes in version 5.21.4
188 perl5213delta Perl changes in version 5.21.3
189 perl5212delta Perl changes in version 5.21.2
190 perl5211delta Perl changes in version 5.21.1
191 perl5210delta Perl changes in version 5.21.0
2b85b119 192 perl5202delta Perl changes in version 5.20.2
0c54b9fe 193 perl5201delta Perl changes in version 5.20.1
d1148309 194 perl5200delta Perl changes in version 5.20.0
e990b849 195 perl5184delta Perl changes in version 5.18.4
7b97958f 196 perl5182delta Perl changes in version 5.18.2
f4e35152 197 perl5181delta Perl changes in version 5.18.1
f13a3008 198 perl5180delta Perl changes in version 5.18.0
eaf7bcbf 199 perl5163delta Perl changes in version 5.16.3
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200 perl5162delta Perl changes in version 5.16.2
201 perl5161delta Perl changes in version 5.16.1
05c8f9ed 202 perl5160delta Perl changes in version 5.16.0
1e5cc764 203 perl5144delta Perl changes in version 5.14.4
70ce046e 204 perl5143delta Perl changes in version 5.14.3
77efd0f7 205 perl5142delta Perl changes in version 5.14.2
10288c7a 206 perl5141delta Perl changes in version 5.14.1
066dc4d9 207 perl5140delta Perl changes in version 5.14.0
a5caed3e 208 perl5125delta Perl changes in version 5.12.5
0b67f426 209 perl5124delta Perl changes in version 5.12.4
6c5f5efa 210 perl5123delta Perl changes in version 5.12.3
e71d1a7d 211 perl5122delta Perl changes in version 5.12.2
bdfb6cc8 212 perl5121delta Perl changes in version 5.12.1
20d57231 213 perl5120delta Perl changes in version 5.12.0
7cdf958d 214 perl5101delta Perl changes in version 5.10.1
7120b314 215 perl5100delta Perl changes in version 5.10.0
fc5be808 216 perl589delta Perl changes in version 5.8.9
c11a53c6 217 perl588delta Perl changes in version 5.8.8
315ba985 218 perl587delta Perl changes in version 5.8.7
e4bb216d 219 perl586delta Perl changes in version 5.8.6
07e9b5fe 220 perl585delta Perl changes in version 5.8.5
5f15c94e 221 perl584delta Perl changes in version 5.8.4
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222 perl583delta Perl changes in version 5.8.3
223 perl582delta Perl changes in version 5.8.2
b6235c4f 224 perl581delta Perl changes in version 5.8.1
2e038148 225 perl58delta Perl changes in version 5.8.0
493a87da 226 perl561delta Perl changes in version 5.6.1
41630250 227 perl56delta Perl changes in version 5.6
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228 perl5005delta Perl changes in version 5.005
229 perl5004delta Perl changes in version 5.004
d516a115 230
42e73e1c 231 perlexperiment A listing of experimental features in Perl
232
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233 perlartistic Perl Artistic License
234 perlgpl GNU General Public License
235
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236=head2 Language-Specific
237
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238=for buildtoc flag +r
239
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240 perlcn Perl for Simplified Chinese (in EUC-CN)
241 perljp Perl for Japanese (in EUC-JP)
242 perlko Perl for Korean (in EUC-KR)
243 perltw Perl for Traditional Chinese (in Big5)
244
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245=head2 Platform-Specific
246
37d4d706 247 perlaix Perl notes for AIX
a83b6f46 248 perlamiga Perl notes for AmigaOS
6001596e 249 perlandroid Perl notes for Android
dc5c060f 250 perlbs2000 Perl notes for POSIX-BC BS2000
a1f19229 251 perlce Perl notes for WinCE
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252 perlcygwin Perl notes for Cygwin
253 perldos Perl notes for DOS
41630250 254 perlfreebsd Perl notes for FreeBSD
f6706af3 255 perlhaiku Perl notes for Haiku
49877630 256 perlhpux Perl notes for HP-UX
a83b6f46 257 perlhurd Perl notes for Hurd
469e7be4 258 perlirix Perl notes for Irix
991e8403 259 perllinux Perl notes for Linux
26d9b02f 260 perlmacos Perl notes for Mac OS (Classic)
0d53b15f 261 perlmacosx Perl notes for Mac OS X
41630250 262 perlnetware Perl notes for NetWare
b0846812 263 perlopenbsd Perl notes for OpenBSD
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264 perlos2 Perl notes for OS/2
265 perlos390 Perl notes for OS/390
522b859a 266 perlos400 Perl notes for OS/400
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267 perlplan9 Perl notes for Plan 9
268 perlqnx Perl notes for QNX
2f08ed66 269 perlriscos Perl notes for RISC OS
d420ca49 270 perlsolaris Perl notes for Solaris
27da23d5 271 perlsymbian Perl notes for Symbian
58534900 272 perlsynology Perl notes for Synology
772ff3b9 273 perltru64 Perl notes for Tru64
49877630 274 perlvms Perl notes for VMS
9a997319 275 perlvos Perl notes for Stratus VOS
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276 perlwin32 Perl notes for Windows
277
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278=for buildtoc flag -r
279
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280=head2 Stubs for Deleted Documents
281
282 perlboot
283 perlbot
9ab63835 284 perlrepository
5d0b49e8 285 perltodo
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286 perltooc
287 perltoot
288
0aef0fe5 289=for buildtoc __END__
35dec5db 290
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291On a Unix-like system, these documentation files will usually also be
292available as manpages for use with the F<man> program.
a0d0e21e 293
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294Some documentation is not available as man pages, so if a
295cross-reference is not found by man, try it with L<perldoc>. Perldoc can
296also take you directly to documentation for functions (with the B<-f>
297switch). See C<perldoc --help> (or C<perldoc perldoc> or C<man perldoc>)
298for other helpful options L<perldoc> has to offer.
299
6b43eec4 300In general, if something strange has gone wrong with your program and you're
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301not sure where you should look for help, try making your code comply with
302B<use strict> and B<use warnings>. These will often point out exactly
303where the trouble is.
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304
305=head1 DESCRIPTION
306
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307Perl officially stands for Practical Extraction and Report Language,
308except when it doesn't.
309
72033c14 310Perl was originally a language optimized for scanning arbitrary
a0d0e21e 311text files, extracting information from those text files, and printing
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312reports based on that information. It quickly became a good language
313for many system management tasks. Over the years, Perl has grown into
b6538e4f 314a general-purpose programming language. It's widely used for everything
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315from quick "one-liners" to full-scale application development.
316
317The language is intended to be practical (easy to use, efficient,
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318complete) rather than beautiful (tiny, elegant, minimal). It combines
319(in the author's opinion, anyway) some of the best features of B<sed>,
0e7bd06d 320B<awk>, and B<sh>, making it familiar and easy to use for Unix users to
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321whip up quick solutions to annoying problems. Its general-purpose
322programming facilities support procedural, functional, and
323object-oriented programming paradigms, making Perl a comfortable
324language for the long haul on major projects, whatever your bent.
325
326Perl's roots in text processing haven't been forgotten over the years.
327It still boasts some of the most powerful regular expressions to be
328found anywhere, and its support for Unicode text is world-class. It
329handles all kinds of structured text, too, through an extensive
330collection of extensions. Those libraries, collected in the CPAN,
331provide ready-made solutions to an astounding array of problems. When
332they haven't set the standard themselves, they steal from the best
333-- just like Perl itself.
a0d0e21e 334
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335=head1 AVAILABILITY
336
14218588 337Perl is available for most operating systems, including virtually
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338all Unix-like platforms. See L<perlport/"Supported Platforms">
339for a listing.
8bc4a6bb 340
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341=head1 ENVIRONMENT
342
1e422769 343See L<perlrun>.
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344
345=head1 AUTHOR
346
19799a22 347Larry Wall <larry@wall.org>, with the help of oodles of other folks.
a0d0e21e 348
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349If your Perl success stories and testimonials may be of help to others
350who wish to advocate the use of Perl in their applications,
351or if you wish to simply express your gratitude to Larry and the
19799a22 352Perl developers, please write to perl-thanks@perl.org .
a99b1639 353
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354=head1 FILES
355
5f05dabc 356 "@INC" locations of perl libraries
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357
358=head1 SEE ALSO
359
c5f69108 360 http://www.perl.org/ the Perl homepage
da9e6348 361 http://www.perl.com/ Perl articles (O'Reilly)
f6b3c421 362 http://www.cpan.org/ the Comprehensive Perl Archive
c5f69108 363 http://www.pm.org/ the Perl Mongers
19799a22 364
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365=head1 DIAGNOSTICS
366
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367Using the C<use strict> pragma ensures that all variables are properly
368declared and prevents other misuses of legacy Perl features.
369
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370The C<use warnings> pragma produces some lovely diagnostics. One can
371also use the B<-w> flag, but its use is normally discouraged, because
372it gets applied to all executed Perl code, including that not under
373your control.
a0d0e21e 374
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375See L<perldiag> for explanations of all Perl's diagnostics. The C<use
376diagnostics> pragma automatically turns Perl's normally terse warnings
377and errors into these longer forms.
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378
379Compilation errors will tell you the line number of the error, with an
380indication of the next token or token type that was to be examined.
14218588 381(In a script passed to Perl via B<-e> switches, each
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382B<-e> is counted as one line.)
383
384Setuid scripts have additional constraints that can produce error
385messages such as "Insecure dependency". See L<perlsec>.
386
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387Did we mention that you should definitely consider using the B<use warnings>
388pragma?
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389
390=head1 BUGS
391
71b5b092 392The behavior implied by the B<use warnings> pragma is not mandatory.
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393
394Perl is at the mercy of your machine's definitions of various
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395operations such as type casting, atof(), and floating-point
396output with sprintf().
a0d0e21e 397
748a9306 398If your stdio requires a seek or eof between reads and writes on a
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399particular stream, so does Perl. (This doesn't apply to sysread()
400and syswrite().)
401
402While none of the built-in data types have any arbitrary size limits
403(apart from memory size), there are still a few arbitrary limits: a
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404given variable name may not be longer than 251 characters. Line numbers
405displayed by diagnostics are internally stored as short integers,
406so they are limited to a maximum of 65535 (higher numbers usually being
407affected by wraparound).
a0d0e21e 408
b0607b7a 409You may mail your bug reports (be sure to include full configuration
19799a22 410information as output by the myconfig program in the perl source
7f2de2d2 411tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
7f89f796 412in compiling perl, the L<perlbug> script in the F<utils/> subdirectory
19799a22 413can be used to help mail in a bug report.
4633a7c4 414
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415Perl actually stands for Pathologically Eclectic Rubbish Lister, but
416don't tell anyone I said that.
417
418=head1 NOTES
419
420The Perl motto is "There's more than one way to do it." Divining
421how many more is left as an exercise to the reader.
422
4633a7c4 423The three principal virtues of a programmer are Laziness,
a0d0e21e 424Impatience, and Hubris. See the Camel Book for why.
16d20bd9 425