| 1 | =head1 NAME |
| 2 | |
| 3 | perl - The Perl 5 language interpreter |
| 4 | |
| 5 | =head1 SYNOPSIS |
| 6 | |
| 7 | B<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 | |
| 18 | For more information on these options, you can run C<perldoc perlrun>. |
| 19 | |
| 20 | =head1 GETTING HELP |
| 21 | |
| 22 | The F<perldoc> program gives you access to all the documentation that comes |
| 23 | with Perl. You can get more documentation, tutorials and community support |
| 24 | online at L<http://www.perl.org/>. |
| 25 | |
| 26 | If you're new to Perl, you should start by running C<perldoc perlintro>, |
| 27 | which is a general intro for beginners and provides some background to help |
| 28 | you navigate the rest of Perl's extensive documentation. Run C<perldoc |
| 29 | perldoc> to learn more things you can do with F<perldoc>. |
| 30 | |
| 31 | For 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 | |
| 37 | flag =g perluniprops perlmodlib perlapi perlintern |
| 38 | flag =go perltoc |
| 39 | flag =ro perlcn perljp perlko perltw |
| 40 | flag = perlvms |
| 41 | |
| 42 | path perlfaq.* cpan/perlfaq/lib/ |
| 43 | path perlglossary cpan/perlfaq/lib/ |
| 44 | path perlxs(?:tut|typemap)? dist/ExtUtils-ParseXS/lib/ |
| 45 | path perldoc cpan/Pod-Perldoc/ |
| 46 | |
| 47 | aux a2p c2ph h2ph h2xs perlbug pl2pm pod2html pod2man s2p 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 | perllexwarn Perl warnings and their control |
| 102 | perldebug Perl debugging |
| 103 | perlvar Perl predefined variables |
| 104 | perlre Perl regular expressions, the rest of the story |
| 105 | perlrebackslash Perl regular expression backslash sequences |
| 106 | perlrecharclass Perl regular expression character classes |
| 107 | perlreref Perl regular expressions quick reference |
| 108 | perlref Perl references, the rest of the story |
| 109 | perlform Perl formats |
| 110 | perlobj Perl objects |
| 111 | perltie Perl objects hidden behind simple variables |
| 112 | perldbmfilter Perl DBM filters |
| 113 | |
| 114 | perlipc Perl interprocess communication |
| 115 | perlfork Perl fork() information |
| 116 | perlnumber Perl number semantics |
| 117 | |
| 118 | perlthrtut Perl threads tutorial |
| 119 | |
| 120 | perlport Perl portability guide |
| 121 | perllocale Perl locale support |
| 122 | perluniintro Perl Unicode introduction |
| 123 | perlunicode Perl Unicode support |
| 124 | perlunicook Perl Unicode cookbook |
| 125 | perlunifaq Perl Unicode FAQ |
| 126 | perluniprops Index of Unicode properties in Perl |
| 127 | perlunitut Perl Unicode tutorial |
| 128 | perlebcdic Considerations for running Perl on EBCDIC platforms |
| 129 | |
| 130 | perlsec Perl security |
| 131 | |
| 132 | perlmod Perl modules: how they work |
| 133 | perlmodlib Perl modules: how to write and use |
| 134 | perlmodstyle Perl modules: how to write modules with style |
| 135 | perlmodinstall Perl modules: how to install from CPAN |
| 136 | perlnewmod Perl modules: preparing a new module for distribution |
| 137 | perlpragma Perl modules: writing a user pragma |
| 138 | |
| 139 | perlutil utilities packaged with the Perl distribution |
| 140 | |
| 141 | perlfilter Perl source filters |
| 142 | |
| 143 | perldtrace Perl's support for DTrace |
| 144 | |
| 145 | perlglossary Perl Glossary |
| 146 | |
| 147 | =head2 Internals and C Language Interface |
| 148 | |
| 149 | perlembed Perl ways to embed perl in your C or C++ application |
| 150 | perldebguts Perl debugging guts and tips |
| 151 | perlxstut Perl XS tutorial |
| 152 | perlxs Perl XS application programming interface |
| 153 | perlxstypemap Perl XS C/Perl type conversion tools |
| 154 | perlclib Internal replacements for standard C library functions |
| 155 | perlguts Perl internal functions for those doing extensions |
| 156 | perlcall Perl calling conventions from C |
| 157 | perlmroapi Perl method resolution plugin interface |
| 158 | perlreapi Perl regular expression plugin interface |
| 159 | perlreguts Perl regular expression engine internals |
| 160 | |
| 161 | perlapi Perl API listing (autogenerated) |
| 162 | perlintern Perl internal functions (autogenerated) |
| 163 | perliol C API for Perl's implementation of IO in Layers |
| 164 | perlapio Perl internal IO abstraction interface |
| 165 | |
| 166 | perlhack Perl hackers guide |
| 167 | perlsource Guide to the Perl source tree |
| 168 | perlinterp Overview of the Perl interpreter source and how it works |
| 169 | perlhacktut Walk through the creation of a simple C code patch |
| 170 | perlhacktips Tips for Perl core C code hacking |
| 171 | perlpolicy Perl development policies |
| 172 | perlgit Using git with the Perl repository |
| 173 | |
| 174 | =head2 Miscellaneous |
| 175 | |
| 176 | perlbook Perl book information |
| 177 | perlcommunity Perl community information |
| 178 | |
| 179 | perldoc Look up Perl documentation in Pod format |
| 180 | |
| 181 | perlhist Perl history records |
| 182 | perldelta Perl changes since previous version |
| 183 | perl5217delta Perl changes in version 5.21.7 |
| 184 | perl5216delta Perl changes in version 5.21.6 |
| 185 | perl5215delta Perl changes in version 5.21.5 |
| 186 | perl5214delta Perl changes in version 5.21.4 |
| 187 | perl5213delta Perl changes in version 5.21.3 |
| 188 | perl5212delta Perl changes in version 5.21.2 |
| 189 | perl5211delta Perl changes in version 5.21.1 |
| 190 | perl5210delta Perl changes in version 5.21.0 |
| 191 | perl5201delta Perl changes in version 5.20.1 |
| 192 | perl5200delta Perl changes in version 5.20.0 |
| 193 | perl5184delta Perl changes in version 5.18.4 |
| 194 | perl5182delta Perl changes in version 5.18.2 |
| 195 | perl5181delta Perl changes in version 5.18.1 |
| 196 | perl5180delta Perl changes in version 5.18.0 |
| 197 | perl5163delta Perl changes in version 5.16.3 |
| 198 | perl5162delta Perl changes in version 5.16.2 |
| 199 | perl5161delta Perl changes in version 5.16.1 |
| 200 | perl5160delta Perl changes in version 5.16.0 |
| 201 | perl5144delta Perl changes in version 5.14.4 |
| 202 | perl5143delta Perl changes in version 5.14.3 |
| 203 | perl5142delta Perl changes in version 5.14.2 |
| 204 | perl5141delta Perl changes in version 5.14.1 |
| 205 | perl5140delta Perl changes in version 5.14.0 |
| 206 | perl5125delta Perl changes in version 5.12.5 |
| 207 | perl5124delta Perl changes in version 5.12.4 |
| 208 | perl5123delta Perl changes in version 5.12.3 |
| 209 | perl5122delta Perl changes in version 5.12.2 |
| 210 | perl5121delta Perl changes in version 5.12.1 |
| 211 | perl5120delta Perl changes in version 5.12.0 |
| 212 | perl5101delta Perl changes in version 5.10.1 |
| 213 | perl5100delta Perl changes in version 5.10.0 |
| 214 | perl589delta Perl changes in version 5.8.9 |
| 215 | perl588delta Perl changes in version 5.8.8 |
| 216 | perl587delta Perl changes in version 5.8.7 |
| 217 | perl586delta Perl changes in version 5.8.6 |
| 218 | perl585delta Perl changes in version 5.8.5 |
| 219 | perl584delta Perl changes in version 5.8.4 |
| 220 | perl583delta Perl changes in version 5.8.3 |
| 221 | perl582delta Perl changes in version 5.8.2 |
| 222 | perl581delta Perl changes in version 5.8.1 |
| 223 | perl58delta Perl changes in version 5.8.0 |
| 224 | perl561delta Perl changes in version 5.6.1 |
| 225 | perl56delta Perl changes in version 5.6 |
| 226 | perl5005delta Perl changes in version 5.005 |
| 227 | perl5004delta Perl changes in version 5.004 |
| 228 | |
| 229 | perlexperiment A listing of experimental features in Perl |
| 230 | |
| 231 | perlartistic Perl Artistic License |
| 232 | perlgpl GNU General Public License |
| 233 | |
| 234 | =head2 Language-Specific |
| 235 | |
| 236 | =for buildtoc flag +r |
| 237 | |
| 238 | perlcn Perl for Simplified Chinese (in EUC-CN) |
| 239 | perljp Perl for Japanese (in EUC-JP) |
| 240 | perlko Perl for Korean (in EUC-KR) |
| 241 | perltw Perl for Traditional Chinese (in Big5) |
| 242 | |
| 243 | =head2 Platform-Specific |
| 244 | |
| 245 | perlaix Perl notes for AIX |
| 246 | perlamiga Perl notes for AmigaOS |
| 247 | perlandroid Perl notes for Android |
| 248 | perlbs2000 Perl notes for POSIX-BC BS2000 |
| 249 | perlce Perl notes for WinCE |
| 250 | perlcygwin Perl notes for Cygwin |
| 251 | perldos Perl notes for DOS |
| 252 | perlfreebsd Perl notes for FreeBSD |
| 253 | perlhaiku Perl notes for Haiku |
| 254 | perlhpux Perl notes for HP-UX |
| 255 | perlhurd Perl notes for Hurd |
| 256 | perlirix Perl notes for Irix |
| 257 | perllinux Perl notes for Linux |
| 258 | perlmacos Perl notes for Mac OS (Classic) |
| 259 | perlmacosx Perl notes for Mac OS X |
| 260 | perlnetware Perl notes for NetWare |
| 261 | perlopenbsd Perl notes for OpenBSD |
| 262 | perlos2 Perl notes for OS/2 |
| 263 | perlos390 Perl notes for OS/390 |
| 264 | perlos400 Perl notes for OS/400 |
| 265 | perlplan9 Perl notes for Plan 9 |
| 266 | perlqnx Perl notes for QNX |
| 267 | perlriscos Perl notes for RISC OS |
| 268 | perlsolaris Perl notes for Solaris |
| 269 | perlsymbian Perl notes for Symbian |
| 270 | perlsynology Perl notes for Synology |
| 271 | perltru64 Perl notes for Tru64 |
| 272 | perlvms Perl notes for VMS |
| 273 | perlvos Perl notes for Stratus VOS |
| 274 | perlwin32 Perl notes for Windows |
| 275 | |
| 276 | =for buildtoc flag -r |
| 277 | |
| 278 | =head2 Stubs for Deleted Documents |
| 279 | |
| 280 | perlboot |
| 281 | perlbot |
| 282 | perlrepository |
| 283 | perltodo |
| 284 | perltooc |
| 285 | perltoot |
| 286 | |
| 287 | =for buildtoc __END__ |
| 288 | |
| 289 | On a Unix-like system, these documentation files will usually also be |
| 290 | available as manpages for use with the F<man> program. |
| 291 | |
| 292 | Some documentation is not available as man pages, so if a |
| 293 | cross-reference is not found by man, try it with L<perldoc>. Perldoc can |
| 294 | also take you directly to documentation for functions (with the B<-f> |
| 295 | switch). See C<perldoc --help> (or C<perldoc perldoc> or C<man perldoc>) |
| 296 | for other helpful options L<perldoc> has to offer. |
| 297 | |
| 298 | In general, if something strange has gone wrong with your program and you're |
| 299 | not sure where you should look for help, try making your code comply with |
| 300 | B<use strict> and B<use warnings>. These will often point out exactly |
| 301 | where the trouble is. |
| 302 | |
| 303 | =head1 DESCRIPTION |
| 304 | |
| 305 | Perl officially stands for Practical Extraction and Report Language, |
| 306 | except when it doesn't. |
| 307 | |
| 308 | Perl was originally a language optimized for scanning arbitrary |
| 309 | text files, extracting information from those text files, and printing |
| 310 | reports based on that information. It quickly became a good language |
| 311 | for many system management tasks. Over the years, Perl has grown into |
| 312 | a general-purpose programming language. It's widely used for everything |
| 313 | from quick "one-liners" to full-scale application development. |
| 314 | |
| 315 | The language is intended to be practical (easy to use, efficient, |
| 316 | complete) rather than beautiful (tiny, elegant, minimal). It combines |
| 317 | (in the author's opinion, anyway) some of the best features of B<sed>, |
| 318 | B<awk>, and B<sh>, making it familiar and easy to use for Unix users to |
| 319 | whip up quick solutions to annoying problems. Its general-purpose |
| 320 | programming facilities support procedural, functional, and |
| 321 | object-oriented programming paradigms, making Perl a comfortable |
| 322 | language for the long haul on major projects, whatever your bent. |
| 323 | |
| 324 | Perl's roots in text processing haven't been forgotten over the years. |
| 325 | It still boasts some of the most powerful regular expressions to be |
| 326 | found anywhere, and its support for Unicode text is world-class. It |
| 327 | handles all kinds of structured text, too, through an extensive |
| 328 | collection of extensions. Those libraries, collected in the CPAN, |
| 329 | provide ready-made solutions to an astounding array of problems. When |
| 330 | they haven't set the standard themselves, they steal from the best |
| 331 | -- just like Perl itself. |
| 332 | |
| 333 | =head1 AVAILABILITY |
| 334 | |
| 335 | Perl is available for most operating systems, including virtually |
| 336 | all Unix-like platforms. See L<perlport/"Supported Platforms"> |
| 337 | for a listing. |
| 338 | |
| 339 | =head1 ENVIRONMENT |
| 340 | |
| 341 | See L<perlrun>. |
| 342 | |
| 343 | =head1 AUTHOR |
| 344 | |
| 345 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. |
| 346 | |
| 347 | If your Perl success stories and testimonials may be of help to others |
| 348 | who wish to advocate the use of Perl in their applications, |
| 349 | or if you wish to simply express your gratitude to Larry and the |
| 350 | Perl developers, please write to perl-thanks@perl.org . |
| 351 | |
| 352 | =head1 FILES |
| 353 | |
| 354 | "@INC" locations of perl libraries |
| 355 | |
| 356 | =head1 SEE ALSO |
| 357 | |
| 358 | http://www.perl.org/ the Perl homepage |
| 359 | http://www.perl.com/ Perl articles (O'Reilly) |
| 360 | http://www.cpan.org/ the Comprehensive Perl Archive |
| 361 | http://www.pm.org/ the Perl Mongers |
| 362 | |
| 363 | =head1 DIAGNOSTICS |
| 364 | |
| 365 | Using the C<use strict> pragma ensures that all variables are properly |
| 366 | declared and prevents other misuses of legacy Perl features. |
| 367 | |
| 368 | The C<use warnings> pragma produces some lovely diagnostics. One can |
| 369 | also use the B<-w> flag, but its use is normally discouraged, because |
| 370 | it gets applied to all executed Perl code, including that not under |
| 371 | your control. |
| 372 | |
| 373 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use |
| 374 | diagnostics> pragma automatically turns Perl's normally terse warnings |
| 375 | and errors into these longer forms. |
| 376 | |
| 377 | Compilation errors will tell you the line number of the error, with an |
| 378 | indication of the next token or token type that was to be examined. |
| 379 | (In a script passed to Perl via B<-e> switches, each |
| 380 | B<-e> is counted as one line.) |
| 381 | |
| 382 | Setuid scripts have additional constraints that can produce error |
| 383 | messages such as "Insecure dependency". See L<perlsec>. |
| 384 | |
| 385 | Did we mention that you should definitely consider using the B<use warnings> |
| 386 | pragma? |
| 387 | |
| 388 | =head1 BUGS |
| 389 | |
| 390 | The behavior implied by the B<use warnings> pragma is not mandatory. |
| 391 | |
| 392 | Perl is at the mercy of your machine's definitions of various |
| 393 | operations such as type casting, atof(), and floating-point |
| 394 | output with sprintf(). |
| 395 | |
| 396 | If your stdio requires a seek or eof between reads and writes on a |
| 397 | particular stream, so does Perl. (This doesn't apply to sysread() |
| 398 | and syswrite().) |
| 399 | |
| 400 | While none of the built-in data types have any arbitrary size limits |
| 401 | (apart from memory size), there are still a few arbitrary limits: a |
| 402 | given variable name may not be longer than 251 characters. Line numbers |
| 403 | displayed by diagnostics are internally stored as short integers, |
| 404 | so they are limited to a maximum of 65535 (higher numbers usually being |
| 405 | affected by wraparound). |
| 406 | |
| 407 | You may mail your bug reports (be sure to include full configuration |
| 408 | information as output by the myconfig program in the perl source |
| 409 | tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded |
| 410 | in compiling perl, the L<perlbug> script in the F<utils/> subdirectory |
| 411 | can be used to help mail in a bug report. |
| 412 | |
| 413 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but |
| 414 | don't tell anyone I said that. |
| 415 | |
| 416 | =head1 NOTES |
| 417 | |
| 418 | The Perl motto is "There's more than one way to do it." Divining |
| 419 | how many more is left as an exercise to the reader. |
| 420 | |
| 421 | The three principal virtues of a programmer are Laziness, |
| 422 | Impatience, and Hubris. See the Camel Book for why. |
| 423 | |