1=head1 NAME 2 3perl - The Perl 5 language interpreter 4 5=head1 SYNOPSIS 6 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> ]> 12 S<[ B<-C [I<number/list>] >]> 13 S<[ B<-S> ]> 14 S<[ B<-x>[I<dir>] ]> 15 S<[ B<-i>[I<extension>] ]> 16 S<[ [B<-e>|B<-E>] I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...> 17 18For more information on these options, you can run C<perldoc perlrun>. 19 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>. 30 31For ease of access, the Perl manual has been split up into several sections. 32 33=begin buildtoc 34 35# This section is parsed by Porting/pod_lib.pl for use by pod/buildtoc etc 36 37flag =g perlmodlib perlapi perlintern 38flag =go perltoc 39flag =ro perlcn perljp perlko perltw 40flag = perlvms 41 42path perlfaq.* cpan/perlfaq/lib/ 43path perlglossary cpan/perlfaq/lib/ 44path perlxs(?:tut|typemap)? dist/ExtUtils-ParseXS/lib/ 45path perldoc cpan/Pod-Perldoc/ 46 47aux h2ph h2xs perlbug pl2pm pod2html pod2man splain xsubpp 48 49=end buildtoc 50 51=head2 Overview 52 53 perl Perl overview (this section) 54 perlintro Perl introduction for beginners 55 perlrun Perl execution and options 56 perltoc Perl documentation table of contents 57 58=head2 Tutorials 59 60 perlreftut Perl references short introduction 61 perldsc Perl data structures intro 62 perllol Perl data structures: arrays of arrays 63 64 perlrequick Perl regular expressions quick start 65 perlretut Perl regular expressions tutorial 66 67 perlootut Perl OO tutorial for beginners 68 69 perlperf Perl Performance and Optimization Techniques 70 71 perlstyle Perl style guide 72 73 perlcheat Perl cheat sheet 74 perltrap Perl traps for the unwary 75 perldebtut Perl debugging tutorial 76 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 87 88=head2 Reference Manual 89 90 perlsyn Perl syntax 91 perldata Perl data structures 92 perlop Perl operators and precedence 93 perlsub Perl subroutines 94 perlfunc Perl built-in functions 95 perlopentut Perl open() tutorial 96 perlpacktut Perl pack() and unpack() tutorial 97 perlpod Perl plain old documentation 98 perlpodspec Perl plain old documentation format specification 99 perlpodstyle Perl POD style guide 100 perldiag Perl diagnostic messages 101 perldeprecation Perl deprecations 102 perllexwarn Perl warnings and their control 103 perldebug Perl debugging 104 perlvar Perl predefined variables 105 perlre Perl regular expressions, the rest of the story 106 perlrebackslash Perl regular expression backslash sequences 107 perlrecharclass Perl regular expression character classes 108 perlreref Perl regular expressions quick reference 109 perlref Perl references, the rest of the story 110 perlform Perl formats 111 perlobj Perl objects 112 perltie Perl objects hidden behind simple variables 113 perldbmfilter Perl DBM filters 114 115 perlipc Perl interprocess communication 116 perlfork Perl fork() information 117 perlnumber Perl number semantics 118 119 perlthrtut Perl threads tutorial 120 121 perlport Perl portability guide 122 perllocale Perl locale support 123 perluniintro Perl Unicode introduction 124 perlunicode Perl Unicode support 125 perlunicook Perl Unicode cookbook 126 perlunifaq Perl Unicode FAQ 127 perluniprops Index of Unicode properties in Perl 128 perlunitut Perl Unicode tutorial 129 perlebcdic Considerations for running Perl on EBCDIC platforms 130 131 perlsec Perl security 132 133 perlmod Perl modules: how they work 134 perlmodlib Perl modules: how to write and use 135 perlmodstyle Perl modules: how to write modules with style 136 perlmodinstall Perl modules: how to install from CPAN 137 perlnewmod Perl modules: preparing a new module for distribution 138 perlpragma Perl modules: writing a user pragma 139 140 perlutil utilities packaged with the Perl distribution 141 142 perlfilter Perl source filters 143 144 perldtrace Perl's support for DTrace 145 146 perlglossary Perl Glossary 147 148=head2 Internals and C Language Interface 149 150 perlembed Perl ways to embed perl in your C or C++ application 151 perldebguts Perl debugging guts and tips 152 perlxstut Perl XS tutorial 153 perlxs Perl XS application programming interface 154 perlxstypemap Perl XS C/Perl type conversion tools 155 perlclib Internal replacements for standard C library functions 156 perlguts Perl internal functions for those doing extensions 157 perlcall Perl calling conventions from C 158 perlmroapi Perl method resolution plugin interface 159 perlreapi Perl regular expression plugin interface 160 perlreguts Perl regular expression engine internals 161 162 perlapi Perl API listing (autogenerated) 163 perlintern Perl internal functions (autogenerated) 164 perliol C API for Perl's implementation of IO in Layers 165 perlapio Perl internal IO abstraction interface 166 167 perlhack Perl hackers guide 168 perlsource Guide to the Perl source tree 169 perlinterp Overview of the Perl interpreter source and how it works 170 perlhacktut Walk through the creation of a simple C code patch 171 perlhacktips Tips for Perl core C code hacking 172 perlpolicy Perl development policies 173 perlgit Using git with the Perl repository 174 175=head2 Miscellaneous 176 177 perlbook Perl book information 178 perlcommunity Perl community information 179 180 perldoc Look up Perl documentation in Pod format 181 182 perlhist Perl history records 183 perldelta Perl changes since previous version 184 perl5302delta Perl changes in version 5.30.2 185 perl5301delta Perl changes in version 5.30.1 186 perl5300delta Perl changes in version 5.30.0 187 perl5282delta Perl changes in version 5.28.2 188 perl5281delta Perl changes in version 5.28.1 189 perl5280delta Perl changes in version 5.28.0 190 perl5263delta Perl changes in version 5.26.3 191 perl5262delta Perl changes in version 5.26.2 192 perl5261delta Perl changes in version 5.26.1 193 perl5260delta Perl changes in version 5.26.0 194 perl5244delta Perl changes in version 5.24.4 195 perl5243delta Perl changes in version 5.24.3 196 perl5242delta Perl changes in version 5.24.2 197 perl5241delta Perl changes in version 5.24.1 198 perl5240delta Perl changes in version 5.24.0 199 perl5224delta Perl changes in version 5.22.4 200 perl5223delta Perl changes in version 5.22.3 201 perl5222delta Perl changes in version 5.22.2 202 perl5221delta Perl changes in version 5.22.1 203 perl5220delta Perl changes in version 5.22.0 204 perl5203delta Perl changes in version 5.20.3 205 perl5202delta Perl changes in version 5.20.2 206 perl5201delta Perl changes in version 5.20.1 207 perl5200delta Perl changes in version 5.20.0 208 perl5184delta Perl changes in version 5.18.4 209 perl5182delta Perl changes in version 5.18.2 210 perl5181delta Perl changes in version 5.18.1 211 perl5180delta Perl changes in version 5.18.0 212 perl5163delta Perl changes in version 5.16.3 213 perl5162delta Perl changes in version 5.16.2 214 perl5161delta Perl changes in version 5.16.1 215 perl5160delta Perl changes in version 5.16.0 216 perl5144delta Perl changes in version 5.14.4 217 perl5143delta Perl changes in version 5.14.3 218 perl5142delta Perl changes in version 5.14.2 219 perl5141delta Perl changes in version 5.14.1 220 perl5140delta Perl changes in version 5.14.0 221 perl5125delta Perl changes in version 5.12.5 222 perl5124delta Perl changes in version 5.12.4 223 perl5123delta Perl changes in version 5.12.3 224 perl5122delta Perl changes in version 5.12.2 225 perl5121delta Perl changes in version 5.12.1 226 perl5120delta Perl changes in version 5.12.0 227 perl5101delta Perl changes in version 5.10.1 228 perl5100delta Perl changes in version 5.10.0 229 perl589delta Perl changes in version 5.8.9 230 perl588delta Perl changes in version 5.8.8 231 perl587delta Perl changes in version 5.8.7 232 perl586delta Perl changes in version 5.8.6 233 perl585delta Perl changes in version 5.8.5 234 perl584delta Perl changes in version 5.8.4 235 perl583delta Perl changes in version 5.8.3 236 perl582delta Perl changes in version 5.8.2 237 perl581delta Perl changes in version 5.8.1 238 perl58delta Perl changes in version 5.8.0 239 perl561delta Perl changes in version 5.6.1 240 perl56delta Perl changes in version 5.6 241 perl5005delta Perl changes in version 5.005 242 perl5004delta Perl changes in version 5.004 243 244 perlexperiment A listing of experimental features in Perl 245 246 perlartistic Perl Artistic License 247 perlgpl GNU General Public License 248 249=head2 Language-Specific 250 251=for buildtoc flag +r 252 253 perlcn Perl for Simplified Chinese (in EUC-CN) 254 perljp Perl for Japanese (in EUC-JP) 255 perlko Perl for Korean (in EUC-KR) 256 perltw Perl for Traditional Chinese (in Big5) 257 258=head2 Platform-Specific 259 260 perlaix Perl notes for AIX 261 perlamiga Perl notes for AmigaOS 262 perlandroid Perl notes for Android 263 perlbs2000 Perl notes for POSIX-BC BS2000 264 perlce Perl notes for WinCE 265 perlcygwin Perl notes for Cygwin 266 perldos Perl notes for DOS 267 perlfreebsd Perl notes for FreeBSD 268 perlhaiku Perl notes for Haiku 269 perlhpux Perl notes for HP-UX 270 perlhurd Perl notes for Hurd 271 perlirix Perl notes for Irix 272 perllinux Perl notes for Linux 273 perlmacos Perl notes for Mac OS (Classic) 274 perlmacosx Perl notes for Mac OS X 275 perlnetware Perl notes for NetWare 276 perlopenbsd Perl notes for OpenBSD 277 perlos2 Perl notes for OS/2 278 perlos390 Perl notes for OS/390 279 perlos400 Perl notes for OS/400 280 perlplan9 Perl notes for Plan 9 281 perlqnx Perl notes for QNX 282 perlriscos Perl notes for RISC OS 283 perlsolaris Perl notes for Solaris 284 perlsymbian Perl notes for Symbian 285 perlsynology Perl notes for Synology 286 perltru64 Perl notes for Tru64 287 perlvms Perl notes for VMS 288 perlvos Perl notes for Stratus VOS 289 perlwin32 Perl notes for Windows 290 291=for buildtoc flag -r 292 293=head2 Stubs for Deleted Documents 294 295 perlboot 296 perlbot 297 perlrepository 298 perltodo 299 perltooc 300 perltoot 301 302=for buildtoc __END__ 303 304On a Unix-like system, these documentation files will usually also be 305available as manpages for use with the F<man> program. 306 307Some documentation is not available as man pages, so if a 308cross-reference is not found by man, try it with L<perldoc>. Perldoc can 309also take you directly to documentation for functions (with the B<-f> 310switch). See C<perldoc --help> (or C<perldoc perldoc> or C<man perldoc>) 311for other helpful options L<perldoc> has to offer. 312 313In general, if something strange has gone wrong with your program and you're 314not sure where you should look for help, try making your code comply with 315B<use strict> and B<use warnings>. These will often point out exactly 316where the trouble is. 317 318=head1 DESCRIPTION 319 320Perl officially stands for Practical Extraction and Report Language, 321except when it doesn't. 322 323Perl was originally a language optimized for scanning arbitrary 324text files, extracting information from those text files, and printing 325reports based on that information. It quickly became a good language 326for many system management tasks. Over the years, Perl has grown into 327a general-purpose programming language. It's widely used for everything 328from quick "one-liners" to full-scale application development. 329 330The language is intended to be practical (easy to use, efficient, 331complete) rather than beautiful (tiny, elegant, minimal). It combines 332(in the author's opinion, anyway) some of the best features of B<sed>, 333B<awk>, and B<sh>, making it familiar and easy to use for Unix users to 334whip up quick solutions to annoying problems. Its general-purpose 335programming facilities support procedural, functional, and 336object-oriented programming paradigms, making Perl a comfortable 337language for the long haul on major projects, whatever your bent. 338 339Perl's roots in text processing haven't been forgotten over the years. 340It still boasts some of the most powerful regular expressions to be 341found anywhere, and its support for Unicode text is world-class. It 342handles all kinds of structured text, too, through an extensive 343collection of extensions. Those libraries, collected in the CPAN, 344provide ready-made solutions to an astounding array of problems. When 345they haven't set the standard themselves, they steal from the best 346-- just like Perl itself. 347 348=head1 AVAILABILITY 349 350Perl is available for most operating systems, including virtually 351all Unix-like platforms. See L<perlport/"Supported Platforms"> 352for a listing. 353 354=head1 ENVIRONMENT 355 356See L<perlrun>. 357 358=head1 AUTHOR 359 360Larry Wall <larry@wall.org>, with the help of oodles of other folks. 361 362If your Perl success stories and testimonials may be of help to others 363who wish to advocate the use of Perl in their applications, 364or if you wish to simply express your gratitude to Larry and the 365Perl developers, please write to perl-thanks@perl.org . 366 367=head1 FILES 368 369 "@INC" locations of perl libraries 370 371"@INC" above is a reference to the built-in variable of the same name; 372see L<perlvar> for more information. 373 374=head1 SEE ALSO 375 376 http://www.perl.org/ the Perl homepage 377 http://www.perl.com/ Perl articles (O'Reilly) 378 http://www.cpan.org/ the Comprehensive Perl Archive 379 http://www.pm.org/ the Perl Mongers 380 381=head1 DIAGNOSTICS 382 383Using the C<use strict> pragma ensures that all variables are properly 384declared and prevents other misuses of legacy Perl features. 385 386The C<use warnings> pragma produces some lovely diagnostics. One can 387also use the B<-w> flag, but its use is normally discouraged, because 388it gets applied to all executed Perl code, including that not under 389your control. 390 391See L<perldiag> for explanations of all Perl's diagnostics. The C<use 392diagnostics> pragma automatically turns Perl's normally terse warnings 393and errors into these longer forms. 394 395Compilation errors will tell you the line number of the error, with an 396indication of the next token or token type that was to be examined. 397(In a script passed to Perl via B<-e> switches, each 398B<-e> is counted as one line.) 399 400Setuid scripts have additional constraints that can produce error 401messages such as "Insecure dependency". See L<perlsec>. 402 403Did we mention that you should definitely consider using the B<use warnings> 404pragma? 405 406=head1 BUGS 407 408The behavior implied by the B<use warnings> pragma is not mandatory. 409 410Perl is at the mercy of your machine's definitions of various 411operations such as type casting, atof(), and floating-point 412output with sprintf(). 413 414If your stdio requires a seek or eof between reads and writes on a 415particular stream, so does Perl. (This doesn't apply to sysread() 416and syswrite().) 417 418While none of the built-in data types have any arbitrary size limits 419(apart from memory size), there are still a few arbitrary limits: a 420given variable name may not be longer than 251 characters. Line numbers 421displayed by diagnostics are internally stored as short integers, 422so they are limited to a maximum of 65535 (higher numbers usually being 423affected by wraparound). 424 425You may submit your bug reports (be sure to include full configuration 426information as output by the myconfig program in the perl source 427tree, or by C<perl -V>) to L<https://github.com/Perl/perl5/issues>. 428 429Perl actually stands for Pathologically Eclectic Rubbish Lister, but 430don't tell anyone I said that. 431 432=head1 NOTES 433 434The Perl motto is "There's more than one way to do it." Divining 435how many more is left as an exercise to the reader. 436 437The three principal virtues of a programmer are Laziness, 438Impatience, and Hubris. See the Camel Book for why. 439 440