3 perl - Practical Extraction and Report Language
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> ]...>
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.
19 For ease of access, the Perl manual has been split up into several sections.
23 perl Perl overview (this section)
24 perlintro Perl introduction for beginners
25 perltoc Perl documentation table of contents
29 perlreftut Perl references short introduction
30 perldsc Perl data structures intro
31 perllol Perl data structures: arrays of arrays
33 perlrequick Perl regular expressions quick start
34 perlretut Perl regular expressions tutorial
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
41 perlstyle Perl style guide
43 perltrap Perl traps for the unwary
44 perldebtut Perl debugging tutorial
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
53 perlfaq7 Perl Language Issues
54 perlfaq8 System Interaction
57 =head2 Reference Manual
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 perlpod Perl plain old documentation
66 perlpodspec Perl plain old documentation format specification
67 perlrun Perl execution and options
68 perldiag Perl diagnostic messages
69 perllexwarn Perl warnings and their control
70 perldebug Perl debugging
71 perlvar Perl predefined variables
72 perlre Perl regular expressions, the rest of the story
73 perlref Perl references, the rest of the story
76 perltie Perl objects hidden behind simple variables
77 perldbmfilter Perl DBM filters
79 perlipc Perl interprocess communication
80 perlfork Perl fork() information
81 perlnumber Perl number semantics
83 perlthrtut Perl threads tutorial
84 perlothrtut Perl threads tutorial
86 perlport Perl portability guide
87 perllocale Perl locale support
88 perlunicode Perl unicode support
89 perlebcdic Considerations for running Perl on EBCDIC platforms
93 perlmod Perl modules: how they work
94 perlmodlib Perl modules: how to write and use
95 perlmodstyle Perl modules: how to write modules with style
96 perlmodinstall Perl modules: how to install from CPAN
97 perlnewmod Perl modules: preparing a new module for distribution
99 perlutil utilities packaged with the Perl distribution
101 perlcompile Perl compiler suite intro
103 perlfilter Perl source filters
105 =head2 Internals and C Language Interface
107 perlembed Perl ways to embed perl in your C or C++ application
108 perldebguts Perl debugging guts and tips
109 perlxstut Perl XS tutorial
110 perlxs Perl XS application programming interface
111 perlclib Internal replacements for standard C library functions
112 perlguts Perl internal functions for those doing extensions
113 perlcall Perl calling conventions from C
115 perlapi Perl API listing (autogenerated)
116 perlintern Perl internal functions (autogenerated)
117 perliol C API for Perl's implementation of IO in Layers
118 perlapio Perl internal IO abstraction interface
120 perlhack Perl hackers guide
124 perlbook Perl book information
125 perltodo Perl things to do
127 perlhist Perl history records
128 perldelta Perl changes since previous version
129 perl572delta Perl changes in version 5.7.2
130 perl571delta Perl changes in version 5.7.1
131 perl570delta Perl changes in version 5.7.0
132 perl56delta Perl changes in version 5.6
133 perl5005delta Perl changes in version 5.005
134 perl5004delta Perl changes in version 5.004
136 =head2 Platform-Specific
138 perlaix Perl notes for AIX
139 perlamiga Perl notes for AmigaOS
140 perlapollo Perl notes for Apollo DomainOS
141 perlbeos Perl notes for BeOS
142 perlbs2000 Perl notes for POSIX-BC BS2000
143 perlce Perl notes for WinCE
144 perlcygwin Perl notes for Cygwin
145 perldgux Perl notes for DG/UX
146 perldos Perl notes for DOS
147 perlepoc Perl notes for EPOC
148 perlhpux Perl notes for HP-UX
149 perlhurd Perl notes for Hurd
150 perlmachten Perl notes for Power MachTen
151 perlmacos Perl notes for Mac OS (Classic)
152 perlmint Perl notes for MiNT
153 perlmpeix Perl notes for MPE/iX
154 perlnetware Perl notes for NetWare
155 perlos2 Perl notes for OS/2
156 perlos390 Perl notes for OS/390
157 perlplan9 Perl notes for Plan 9
158 perlqnx Perl notes for QNX
159 perlsolaris Perl notes for Solaris
160 perltru64 Perl notes for Tru64
161 perluts Perl notes for UTS
162 perlvmesa Perl notes for VM/ESA
163 perlvms Perl notes for VMS
164 perlvos Perl notes for Stratus VOS
165 perlwin32 Perl notes for Windows
168 By default, the manpages listed above are installed in the
169 F</usr/local/man/> directory.
171 Extensive additional documentation for Perl modules is available. The
172 default configuration for perl will place this additional documentation
173 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
174 subdirectory of the Perl library directory). Some of this additional
175 documentation is distributed standard with Perl, but you'll also find
176 documentation for third-party modules there.
178 You should be able to view Perl's documentation with your man(1)
179 program by including the proper directories in the appropriate start-up
180 files, or in the MANPATH environment variable. To find out where the
181 configuration has installed the manpages, type:
185 If the directories have a common stem, such as F</usr/local/man/man1>
186 and F</usr/local/man/man3>, you need only to add that stem
187 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
188 environment variable. If they do not share a stem, you'll have to add
191 If that doesn't work for some reason, you can still use the
192 supplied F<perldoc> script to view module information. You might
193 also look into getting a replacement man program.
195 If something strange has gone wrong with your program and you're not
196 sure where you should look for help, try the B<-w> switch first. It
197 will often point out exactly where the trouble is.
201 Perl is a language optimized for scanning arbitrary
202 text files, extracting information from those text files, and printing
203 reports based on that information. It's also a good language for many
204 system management tasks. The language is intended to be practical
205 (easy to use, efficient, complete) rather than beautiful (tiny,
208 Perl combines (in the author's opinion, anyway) some of the best
209 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
210 those languages should have little difficulty with it. (Language
211 historians will also note some vestiges of B<csh>, Pascal, and even
212 BASIC-PLUS.) Expression syntax corresponds closely to C
213 expression syntax. Unlike most Unix utilities, Perl does not
214 arbitrarily limit the size of your data--if you've got the memory,
215 Perl can slurp in your whole file as a single string. Recursion is of
216 unlimited depth. And the tables used by hashes (sometimes called
217 "associative arrays") grow as necessary to prevent degraded
218 performance. Perl can use sophisticated pattern matching techniques to
219 scan large amounts of data quickly. Although optimized for
220 scanning text, Perl can also deal with binary data, and can make dbm
221 files look like hashes. Setuid Perl scripts are safer than C programs
222 through a dataflow tracing mechanism that prevents many stupid
225 If you have a problem that would ordinarily use B<sed> or B<awk> or
226 B<sh>, but it exceeds their capabilities or must run a little faster,
227 and you don't want to write the silly thing in C, then Perl may be for
228 you. There are also translators to turn your B<sed> and B<awk>
229 scripts into Perl scripts.
231 But wait, there's more...
233 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
234 rewrite that provides the following additional benefits:
240 modularity and reusability using innumerable modules
242 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
246 embeddable and extensible
248 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
249 L<perlguts>, and L<xsubpp>.
253 roll-your-own magic variables (including multiple simultaneous DBM implementations)
255 Described in L<perltie> and L<AnyDBM_File>.
259 subroutines can now be overridden, autoloaded, and prototyped
261 Described in L<perlsub>.
265 arbitrarily nested data structures and anonymous functions
267 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
271 object-oriented programming
273 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
277 compilability into C code or Perl bytecode
279 Described in L<B> and L<B::Bytecode>.
283 support for light-weight processes (threads)
285 Described in L<perlthrtut> and L<Thread>.
289 support for internationalization, localization, and Unicode
291 Described in L<perllocale> and L<utf8>.
297 Described in L<perlsub>.
301 regular expression enhancements
303 Described in L<perlre>, with additional examples in L<perlop>.
307 enhanced debugger and interactive Perl environment,
308 with integrated editor support
310 Described in L<perldebug>.
314 POSIX 1003.1 compliant library
316 Described in L<POSIX>.
320 Okay, that's I<definitely> enough hype.
324 Perl is available for most operating systems, including virtually
325 all Unix-like platforms. See L<perlport/"Supported Platforms">
334 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
336 If your Perl success stories and testimonials may be of help to others
337 who wish to advocate the use of Perl in their applications,
338 or if you wish to simply express your gratitude to Larry and the
339 Perl developers, please write to perl-thanks@perl.org .
343 "@INC" locations of perl libraries
347 a2p awk to perl translator
348 s2p sed to perl translator
350 http://www.perl.com/ the Perl Home Page
351 http://www.perl.com/CPAN the Comprehensive Perl Archive
355 The C<use warnings> pragma (and the B<-w> switch) produces some
358 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
359 diagnostics> pragma automatically turns Perl's normally terse warnings
360 and errors into these longer forms.
362 Compilation errors will tell you the line number of the error, with an
363 indication of the next token or token type that was to be examined.
364 (In a script passed to Perl via B<-e> switches, each
365 B<-e> is counted as one line.)
367 Setuid scripts have additional constraints that can produce error
368 messages such as "Insecure dependency". See L<perlsec>.
370 Did we mention that you should definitely consider using the B<-w>
375 The B<-w> switch is not mandatory.
377 Perl is at the mercy of your machine's definitions of various
378 operations such as type casting, atof(), and floating-point
379 output with sprintf().
381 If your stdio requires a seek or eof between reads and writes on a
382 particular stream, so does Perl. (This doesn't apply to sysread()
385 While none of the built-in data types have any arbitrary size limits
386 (apart from memory size), there are still a few arbitrary limits: a
387 given variable name may not be longer than 251 characters. Line numbers
388 displayed by diagnostics are internally stored as short integers,
389 so they are limited to a maximum of 65535 (higher numbers usually being
390 affected by wraparound).
392 You may mail your bug reports (be sure to include full configuration
393 information as output by the myconfig program in the perl source
394 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
395 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
396 can be used to help mail in a bug report.
398 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
399 don't tell anyone I said that.
403 The Perl motto is "There's more than one way to do it." Divining
404 how many more is left as an exercise to the reader.
406 The three principal virtues of a programmer are Laziness,
407 Impatience, and Hubris. See the Camel Book for why.