| 1 | =head1 NAME |
| 2 | |
| 3 | perl - Practical Extraction and Report Language |
| 4 | |
| 5 | =head1 SYNOPSIS |
| 6 | |
| 7 | B<perl> S<[ B<-sTuU> ]> S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]> |
| 8 | S<[ B<-cw> ] [ B<-d>[:I<debugger>] ] [ B<-D>[I<number/list>] ]> |
| 9 | S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal>] ]> |
| 10 | S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ]> |
| 11 | S<[ B<-P> ]> S<[ B<-S> ]> S<[ B<-x>[I<dir>] ]> |
| 12 | S<[ B<-i>[I<extension>] ]> S<[ B<-e> I<'command'> ] |
| 13 | [ B<--> ] [ I<programfile> ] [ I<argument> ]...> |
| 14 | |
| 15 | If you're new to Perl, you should start with L<perlintro>, which is a |
| 16 | general intro for beginners and provides some background to help you |
| 17 | navigate the rest of Perl's extensive documentation. |
| 18 | |
| 19 | For ease of access, the Perl manual has been split up into several sections. |
| 20 | |
| 21 | =head2 Overview |
| 22 | |
| 23 | perl Perl overview (this section) |
| 24 | perlintro Perl introduction for beginners |
| 25 | perltoc Perl documentation table of contents |
| 26 | |
| 27 | =head2 Tutorials |
| 28 | |
| 29 | perlreftut Perl references short introduction |
| 30 | perldsc Perl data structures intro |
| 31 | perllol Perl data structures: arrays of arrays |
| 32 | |
| 33 | perlrequick Perl regular expressions quick start |
| 34 | perlretut Perl regular expressions tutorial |
| 35 | |
| 36 | perlboot Perl OO tutorial for beginners |
| 37 | perltoot Perl OO tutorial, part 1 |
| 38 | perltooc Perl OO tutorial, part 2 |
| 39 | perlbot Perl OO tricks and examples |
| 40 | |
| 41 | perlstyle Perl style guide |
| 42 | |
| 43 | perltrap Perl traps for the unwary |
| 44 | perldebtut Perl debugging tutorial |
| 45 | |
| 46 | perlfaq Perl frequently asked questions |
| 47 | perlfaq1 General Questions About Perl |
| 48 | perlfaq2 Obtaining and Learning about Perl |
| 49 | perlfaq3 Programming Tools |
| 50 | perlfaq4 Data Manipulation |
| 51 | perlfaq5 Files and Formats |
| 52 | perlfaq6 Regexes |
| 53 | perlfaq7 Perl Language Issues |
| 54 | perlfaq8 System Interaction |
| 55 | perlfaq9 Networking |
| 56 | |
| 57 | =head2 Reference Manual |
| 58 | |
| 59 | perlsyn Perl syntax |
| 60 | perldata Perl data structures |
| 61 | perlop Perl operators and precedence |
| 62 | perlsub Perl subroutines |
| 63 | perlfunc Perl built-in functions |
| 64 | perlopentut Perl open() tutorial |
| 65 | perlpacktut Perl pack() and unpack() tutorial |
| 66 | perlpod Perl plain old documentation |
| 67 | perlpodspec Perl plain old documentation format specification |
| 68 | perlrun Perl execution and options |
| 69 | perldiag Perl diagnostic messages |
| 70 | perllexwarn Perl warnings and their control |
| 71 | perldebug Perl debugging |
| 72 | perlvar Perl predefined variables |
| 73 | perlre Perl regular expressions, the rest of the story |
| 74 | perlref Perl references, the rest of the story |
| 75 | perlform Perl formats |
| 76 | perlobj Perl objects |
| 77 | perltie Perl objects hidden behind simple variables |
| 78 | perldbmfilter Perl DBM filters |
| 79 | |
| 80 | perlipc Perl interprocess communication |
| 81 | perlfork Perl fork() information |
| 82 | perlnumber Perl number semantics |
| 83 | |
| 84 | perlthrtut Perl threads tutorial |
| 85 | perlothrtut Old Perl threads tutorial |
| 86 | |
| 87 | perlport Perl portability guide |
| 88 | perllocale Perl locale support |
| 89 | perluniintro Perl Unicode introduction |
| 90 | perlunicode Perl Unicode support |
| 91 | perlebcdic Considerations for running Perl on EBCDIC platforms |
| 92 | |
| 93 | perlsec Perl security |
| 94 | |
| 95 | perlmod Perl modules: how they work |
| 96 | perlmodlib Perl modules: how to write and use |
| 97 | perlmodstyle Perl modules: how to write modules with style |
| 98 | perlmodinstall Perl modules: how to install from CPAN |
| 99 | perlnewmod Perl modules: preparing a new module for distribution |
| 100 | |
| 101 | perlutil utilities packaged with the Perl distribution |
| 102 | |
| 103 | perlcompile Perl compiler suite intro |
| 104 | |
| 105 | perlfilter Perl source filters |
| 106 | |
| 107 | =head2 Internals and C Language Interface |
| 108 | |
| 109 | perlembed Perl ways to embed perl in your C or C++ application |
| 110 | perldebguts Perl debugging guts and tips |
| 111 | perlxstut Perl XS tutorial |
| 112 | perlxs Perl XS application programming interface |
| 113 | perlclib Internal replacements for standard C library functions |
| 114 | perlguts Perl internal functions for those doing extensions |
| 115 | perlcall Perl calling conventions from C |
| 116 | |
| 117 | perlapi Perl API listing (autogenerated) |
| 118 | perlintern Perl internal functions (autogenerated) |
| 119 | perliol C API for Perl's implementation of IO in Layers |
| 120 | perlapio Perl internal IO abstraction interface |
| 121 | |
| 122 | perlhack Perl hackers guide |
| 123 | |
| 124 | =head2 Miscellaneous |
| 125 | |
| 126 | perlbook Perl book information |
| 127 | perltodo Perl things to do |
| 128 | |
| 129 | perlhist Perl history records |
| 130 | perldelta Perl changes since previous version |
| 131 | perl572delta Perl changes in version 5.7.2 |
| 132 | perl571delta Perl changes in version 5.7.1 |
| 133 | perl570delta Perl changes in version 5.7.0 |
| 134 | perl561delta Perl changes in version 5.6.1 |
| 135 | perl56delta Perl changes in version 5.6 |
| 136 | perl5005delta Perl changes in version 5.005 |
| 137 | perl5004delta Perl changes in version 5.004 |
| 138 | |
| 139 | =head2 Language-Specific |
| 140 | |
| 141 | perlcn Perl for Simplified Chinese (in EUC-CN) |
| 142 | perljp Perl for Japanese (in EUC-JP) |
| 143 | perlko Perl for Korean (in EUC-KR) |
| 144 | perltw Perl for Traditional Chinese (in Big5) |
| 145 | |
| 146 | =head2 Platform-Specific |
| 147 | |
| 148 | perlaix Perl notes for AIX |
| 149 | perlamiga Perl notes for AmigaOS |
| 150 | perlapollo Perl notes for Apollo DomainOS |
| 151 | perlbeos Perl notes for BeOS |
| 152 | perlbs2000 Perl notes for POSIX-BC BS2000 |
| 153 | perlce Perl notes for WinCE |
| 154 | perlcygwin Perl notes for Cygwin |
| 155 | perldgux Perl notes for DG/UX |
| 156 | perldos Perl notes for DOS |
| 157 | perlepoc Perl notes for EPOC |
| 158 | perlfreebsd Perl notes for FreeBSD |
| 159 | perlhpux Perl notes for HP-UX |
| 160 | perlhurd Perl notes for Hurd |
| 161 | perlirix Perl notes for Irix |
| 162 | perlmachten Perl notes for Power MachTen |
| 163 | perlmacos Perl notes for Mac OS (Classic) |
| 164 | perlmint Perl notes for MiNT |
| 165 | perlmpeix Perl notes for MPE/iX |
| 166 | perlnetware Perl notes for NetWare |
| 167 | perlos2 Perl notes for OS/2 |
| 168 | perlos390 Perl notes for OS/390 |
| 169 | perlplan9 Perl notes for Plan 9 |
| 170 | perlqnx Perl notes for QNX |
| 171 | perlsolaris Perl notes for Solaris |
| 172 | perltru64 Perl notes for Tru64 |
| 173 | perluts Perl notes for UTS |
| 174 | perlvmesa Perl notes for VM/ESA |
| 175 | perlvms Perl notes for VMS |
| 176 | perlvos Perl notes for Stratus VOS |
| 177 | perlwin32 Perl notes for Windows |
| 178 | |
| 179 | |
| 180 | By default, the manpages listed above are installed in the |
| 181 | F</usr/local/man/> directory. |
| 182 | |
| 183 | Extensive additional documentation for Perl modules is available. The |
| 184 | default configuration for perl will place this additional documentation |
| 185 | in the F</usr/local/lib/perl5/man> directory (or else in the F<man> |
| 186 | subdirectory of the Perl library directory). Some of this additional |
| 187 | documentation is distributed standard with Perl, but you'll also find |
| 188 | documentation for third-party modules there. |
| 189 | |
| 190 | You should be able to view Perl's documentation with your man(1) |
| 191 | program by including the proper directories in the appropriate start-up |
| 192 | files, or in the MANPATH environment variable. To find out where the |
| 193 | configuration has installed the manpages, type: |
| 194 | |
| 195 | perl -V:man.dir |
| 196 | |
| 197 | If the directories have a common stem, such as F</usr/local/man/man1> |
| 198 | and F</usr/local/man/man3>, you need only to add that stem |
| 199 | (F</usr/local/man>) to your man(1) configuration files or your MANPATH |
| 200 | environment variable. If they do not share a stem, you'll have to add |
| 201 | both stems. |
| 202 | |
| 203 | If that doesn't work for some reason, you can still use the |
| 204 | supplied F<perldoc> script to view module information. You might |
| 205 | also look into getting a replacement man program. |
| 206 | |
| 207 | If something strange has gone wrong with your program and you're not |
| 208 | sure where you should look for help, try the B<-w> switch first. It |
| 209 | will often point out exactly where the trouble is. |
| 210 | |
| 211 | =head1 DESCRIPTION |
| 212 | |
| 213 | Perl is a language optimized for scanning arbitrary |
| 214 | text files, extracting information from those text files, and printing |
| 215 | reports based on that information. It's also a good language for many |
| 216 | system management tasks. The language is intended to be practical |
| 217 | (easy to use, efficient, complete) rather than beautiful (tiny, |
| 218 | elegant, minimal). |
| 219 | |
| 220 | Perl combines (in the author's opinion, anyway) some of the best |
| 221 | features of C, B<sed>, B<awk>, and B<sh>, so people familiar with |
| 222 | those languages should have little difficulty with it. (Language |
| 223 | historians will also note some vestiges of B<csh>, Pascal, and even |
| 224 | BASIC-PLUS.) Expression syntax corresponds closely to C |
| 225 | expression syntax. Unlike most Unix utilities, Perl does not |
| 226 | arbitrarily limit the size of your data--if you've got the memory, |
| 227 | Perl can slurp in your whole file as a single string. Recursion is of |
| 228 | unlimited depth. And the tables used by hashes (sometimes called |
| 229 | "associative arrays") grow as necessary to prevent degraded |
| 230 | performance. Perl can use sophisticated pattern matching techniques to |
| 231 | scan large amounts of data quickly. Although optimized for |
| 232 | scanning text, Perl can also deal with binary data, and can make dbm |
| 233 | files look like hashes. Setuid Perl scripts are safer than C programs |
| 234 | through a dataflow tracing mechanism that prevents many stupid |
| 235 | security holes. |
| 236 | |
| 237 | If you have a problem that would ordinarily use B<sed> or B<awk> or |
| 238 | B<sh>, but it exceeds their capabilities or must run a little faster, |
| 239 | and you don't want to write the silly thing in C, then Perl may be for |
| 240 | you. There are also translators to turn your B<sed> and B<awk> |
| 241 | scripts into Perl scripts. |
| 242 | |
| 243 | But wait, there's more... |
| 244 | |
| 245 | Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete |
| 246 | rewrite that provides the following additional benefits: |
| 247 | |
| 248 | =over 4 |
| 249 | |
| 250 | =item * |
| 251 | |
| 252 | modularity and reusability using innumerable modules |
| 253 | |
| 254 | Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>. |
| 255 | |
| 256 | =item * |
| 257 | |
| 258 | embeddable and extensible |
| 259 | |
| 260 | Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>, |
| 261 | L<perlguts>, and L<xsubpp>. |
| 262 | |
| 263 | =item * |
| 264 | |
| 265 | roll-your-own magic variables (including multiple simultaneous DBM implementations) |
| 266 | |
| 267 | Described in L<perltie> and L<AnyDBM_File>. |
| 268 | |
| 269 | =item * |
| 270 | |
| 271 | subroutines can now be overridden, autoloaded, and prototyped |
| 272 | |
| 273 | Described in L<perlsub>. |
| 274 | |
| 275 | =item * |
| 276 | |
| 277 | arbitrarily nested data structures and anonymous functions |
| 278 | |
| 279 | Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>. |
| 280 | |
| 281 | =item * |
| 282 | |
| 283 | object-oriented programming |
| 284 | |
| 285 | Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>, |
| 286 | and L<perlbot>. |
| 287 | |
| 288 | =item * |
| 289 | |
| 290 | compilability into C code or Perl bytecode |
| 291 | |
| 292 | Described in L<B> and L<B::Bytecode>. |
| 293 | |
| 294 | =item * |
| 295 | |
| 296 | support for light-weight processes (threads) |
| 297 | |
| 298 | Described in L<perlthrtut> and L<Thread>. |
| 299 | |
| 300 | =item * |
| 301 | |
| 302 | support for internationalization, localization, and Unicode |
| 303 | |
| 304 | Described in L<perllocale> and L<utf8>. |
| 305 | |
| 306 | =item * |
| 307 | |
| 308 | lexical scoping |
| 309 | |
| 310 | Described in L<perlsub>. |
| 311 | |
| 312 | =item * |
| 313 | |
| 314 | regular expression enhancements |
| 315 | |
| 316 | Described in L<perlre>, with additional examples in L<perlop>. |
| 317 | |
| 318 | =item * |
| 319 | |
| 320 | enhanced debugger and interactive Perl environment, |
| 321 | with integrated editor support |
| 322 | |
| 323 | Described in L<perldebtut>, L<perldebug> and L<perldebguts>. |
| 324 | |
| 325 | =item * |
| 326 | |
| 327 | POSIX 1003.1 compliant library |
| 328 | |
| 329 | Described in L<POSIX>. |
| 330 | |
| 331 | =back |
| 332 | |
| 333 | Okay, that's I<definitely> enough hype. |
| 334 | |
| 335 | =head1 AVAILABILITY |
| 336 | |
| 337 | Perl is available for most operating systems, including virtually |
| 338 | all Unix-like platforms. See L<perlport/"Supported Platforms"> |
| 339 | for a listing. |
| 340 | |
| 341 | =head1 ENVIRONMENT |
| 342 | |
| 343 | See L<perlrun>. |
| 344 | |
| 345 | =head1 AUTHOR |
| 346 | |
| 347 | Larry Wall <larry@wall.org>, with the help of oodles of other folks. |
| 348 | |
| 349 | If your Perl success stories and testimonials may be of help to others |
| 350 | who wish to advocate the use of Perl in their applications, |
| 351 | or if you wish to simply express your gratitude to Larry and the |
| 352 | Perl developers, please write to perl-thanks@perl.org . |
| 353 | |
| 354 | =head1 FILES |
| 355 | |
| 356 | "@INC" locations of perl libraries |
| 357 | |
| 358 | =head1 SEE ALSO |
| 359 | |
| 360 | a2p awk to perl translator |
| 361 | s2p sed to perl translator |
| 362 | |
| 363 | http://www.perl.com/ the Perl Home Page |
| 364 | http://www.cpan.org/ the Comprehensive Perl Archive |
| 365 | http://www.perl.org/ Perl Mongers (Perl user groups) |
| 366 | |
| 367 | =head1 DIAGNOSTICS |
| 368 | |
| 369 | The C<use warnings> pragma (and the B<-w> switch) produces some |
| 370 | lovely diagnostics. |
| 371 | |
| 372 | See L<perldiag> for explanations of all Perl's diagnostics. The C<use |
| 373 | diagnostics> pragma automatically turns Perl's normally terse warnings |
| 374 | and errors into these longer forms. |
| 375 | |
| 376 | Compilation errors will tell you the line number of the error, with an |
| 377 | indication of the next token or token type that was to be examined. |
| 378 | (In a script passed to Perl via B<-e> switches, each |
| 379 | B<-e> is counted as one line.) |
| 380 | |
| 381 | Setuid scripts have additional constraints that can produce error |
| 382 | messages such as "Insecure dependency". See L<perlsec>. |
| 383 | |
| 384 | Did we mention that you should definitely consider using the B<-w> |
| 385 | switch? |
| 386 | |
| 387 | =head1 BUGS |
| 388 | |
| 389 | The B<-w> switch is not mandatory. |
| 390 | |
| 391 | Perl is at the mercy of your machine's definitions of various |
| 392 | operations such as type casting, atof(), and floating-point |
| 393 | output with sprintf(). |
| 394 | |
| 395 | If your stdio requires a seek or eof between reads and writes on a |
| 396 | particular stream, so does Perl. (This doesn't apply to sysread() |
| 397 | and syswrite().) |
| 398 | |
| 399 | While none of the built-in data types have any arbitrary size limits |
| 400 | (apart from memory size), there are still a few arbitrary limits: a |
| 401 | given variable name may not be longer than 251 characters. Line numbers |
| 402 | displayed by diagnostics are internally stored as short integers, |
| 403 | so they are limited to a maximum of 65535 (higher numbers usually being |
| 404 | affected by wraparound). |
| 405 | |
| 406 | You may mail your bug reports (be sure to include full configuration |
| 407 | information as output by the myconfig program in the perl source |
| 408 | tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded |
| 409 | in compiling perl, the B<perlbug> script in the F<utils/> subdirectory |
| 410 | can be used to help mail in a bug report. |
| 411 | |
| 412 | Perl actually stands for Pathologically Eclectic Rubbish Lister, but |
| 413 | don't tell anyone I said that. |
| 414 | |
| 415 | =head1 NOTES |
| 416 | |
| 417 | The Perl motto is "There's more than one way to do it." Divining |
| 418 | how many more is left as an exercise to the reader. |
| 419 | |
| 420 | The three principal virtues of a programmer are Laziness, |
| 421 | Impatience, and Hubris. See the Camel Book for why. |
| 422 | |