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.
21 perl Perl overview (this section)
22 perlintro Perl introduction for beginners
23 perlfaq Perl frequently asked questions
24 perltoc Perl documentation table of contents
25 perlbook Perl book information
28 perldata Perl data structures
29 perlop Perl operators and precedence
30 perlsub Perl subroutines
31 perlfunc Perl builtin functions
32 perlreftut Perl references short introduction
33 perldsc Perl data structures intro
34 perlrequick Perl regular expressions quick start
35 perlpod Perl plain old documentation
36 perlstyle Perl style guide
37 perltrap Perl traps for the unwary
39 perlrun Perl execution and options
40 perldiag Perl diagnostic messages
41 perllexwarn Perl warnings and their control
42 perldebtut Perl debugging tutorial
43 perldebug Perl debugging
45 perlvar Perl predefined variables
46 perllol Perl data structures: arrays of arrays
47 perlopentut Perl open() tutorial
48 perlretut Perl regular expressions tutorial
50 perlre Perl regular expressions, the rest of the story
51 perlref Perl references, the rest of the story
55 perlboot Perl OO tutorial for beginners
56 perltoot Perl OO tutorial, part 1
57 perltooc Perl OO tutorial, part 2
59 perlbot Perl OO tricks and examples
60 perltie Perl objects hidden behind simple variables
62 perlipc Perl interprocess communication
63 perlfork Perl fork() information
64 perlnumber Perl number semantics
66 perlthrtut Perl threads tutorial
67 perlothrtut Perl old threads tutorial
69 perlport Perl portability guide
70 perllocale Perl locale support
71 perlunicode Perl unicode support
72 perlebcdic Considerations for running Perl on EBCDIC platforms
76 perlmod Perl modules: how they work
77 perlmodinstall Perl modules: how to install from CPAN
78 perlmodlib Perl modules: how to write and use
79 perlmodstyle Perl modules: how to write modules with style
80 perlnewmod Perl modules: preparing a new module for distribution
82 perlfaq1 General Questions About Perl
83 perlfaq2 Obtaining and Learning about Perl
84 perlfaq3 Programming Tools
85 perlfaq4 Data Manipulation
86 perlfaq5 Files and Formats
88 perlfaq7 Perl Language Issues
89 perlfaq8 System Interaction
92 perlcompile Perl compiler suite intro
94 perlembed Perl ways to embed perl in your C or C++ application
95 perldebguts Perl debugging guts and tips
96 perlxstut Perl XS tutorial
97 perlxs Perl XS application programming interface
98 perlclib Internal replacements for standard C library functions
99 perlguts Perl internal functions for those doing extensions
100 perlcall Perl calling conventions from C
101 perlutil utilities packaged with the Perl distribution
102 perlfilter Perl source filters
103 perldbmfilter Perl DBM filters
104 perlapi Perl API listing (autogenerated)
105 perlintern Perl internal functions (autogenerated)
106 perliol C API for Perl's implementation of IO in Layers
107 perlapio Perl internal IO abstraction interface
108 perltodo Perl things to do
109 perlhack Perl hackers guide
111 perlhist Perl history records
112 perldelta Perl changes since previous version
113 perl572delta Perl changes in version 5.7.2
114 perl571delta Perl changes in version 5.7.1
115 perl570delta Perl changes in version 5.7.0
116 perl56delta Perl changes in version 5.6
117 perl5005delta Perl changes in version 5.005
118 perl5004delta Perl changes in version 5.004
120 perlaix Perl notes for AIX
121 perlamiga Perl notes for AmigaOS
122 perlapollo Perl notes for Apollo DomainOS
123 perlbeos Perl notes for BeOS
124 perlbs2000 Perl notes for POSIX-BC BS2000
125 perlce Perl notes for WinCE
126 perlcygwin Perl notes for Cygwin
127 perldgux Perl notes for DG/UX
128 perldos Perl notes for DOS
129 perlepoc Perl notes for EPOC
130 perlhpux Perl notes for HP-UX
131 perlhurd Perl notes for Hurd
132 perlmachten Perl notes for Power MachTen
133 perlmacos Perl notes for Mac OS (Classic)
134 perlmint Perl notes for MiNT
135 perlmpeix Perl notes for MPE/iX
136 perlnetware Perl notes for NetWare
137 perlos2 Perl notes for OS/2
138 perlos390 Perl notes for OS/390
139 perlplan9 Perl notes for Plan 9
140 perlqnx Perl notes for QNX
141 perlsolaris Perl notes for Solaris
142 perltru64 Perl notes for Tru64
143 perluts Perl notes for UTS
144 perlvmesa Perl notes for VM/ESA
145 perlvms Perl notes for VMS
146 perlvos Perl notes for Stratus VOS
147 perlwin32 Perl notes for Windows
149 (If you're intending to read these straight through for the first time,
150 the suggested order will tend to reduce the number of forward references.)
152 By default, the manpages listed above are installed in the
153 F</usr/local/man/> directory.
155 Extensive additional documentation for Perl modules is available. The
156 default configuration for perl will place this additional documentation
157 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
158 subdirectory of the Perl library directory). Some of this additional
159 documentation is distributed standard with Perl, but you'll also find
160 documentation for third-party modules there.
162 You should be able to view Perl's documentation with your man(1)
163 program by including the proper directories in the appropriate start-up
164 files, or in the MANPATH environment variable. To find out where the
165 configuration has installed the manpages, type:
169 If the directories have a common stem, such as F</usr/local/man/man1>
170 and F</usr/local/man/man3>, you need only to add that stem
171 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
172 environment variable. If they do not share a stem, you'll have to add
175 If that doesn't work for some reason, you can still use the
176 supplied F<perldoc> script to view module information. You might
177 also look into getting a replacement man program.
179 If something strange has gone wrong with your program and you're not
180 sure where you should look for help, try the B<-w> switch first. It
181 will often point out exactly where the trouble is.
185 Perl is a language optimized for scanning arbitrary
186 text files, extracting information from those text files, and printing
187 reports based on that information. It's also a good language for many
188 system management tasks. The language is intended to be practical
189 (easy to use, efficient, complete) rather than beautiful (tiny,
192 Perl combines (in the author's opinion, anyway) some of the best
193 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
194 those languages should have little difficulty with it. (Language
195 historians will also note some vestiges of B<csh>, Pascal, and even
196 BASIC-PLUS.) Expression syntax corresponds closely to C
197 expression syntax. Unlike most Unix utilities, Perl does not
198 arbitrarily limit the size of your data--if you've got the memory,
199 Perl can slurp in your whole file as a single string. Recursion is of
200 unlimited depth. And the tables used by hashes (sometimes called
201 "associative arrays") grow as necessary to prevent degraded
202 performance. Perl can use sophisticated pattern matching techniques to
203 scan large amounts of data quickly. Although optimized for
204 scanning text, Perl can also deal with binary data, and can make dbm
205 files look like hashes. Setuid Perl scripts are safer than C programs
206 through a dataflow tracing mechanism that prevents many stupid
209 If you have a problem that would ordinarily use B<sed> or B<awk> or
210 B<sh>, but it exceeds their capabilities or must run a little faster,
211 and you don't want to write the silly thing in C, then Perl may be for
212 you. There are also translators to turn your B<sed> and B<awk>
213 scripts into Perl scripts.
215 But wait, there's more...
217 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
218 rewrite that provides the following additional benefits:
224 modularity and reusability using innumerable modules
226 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
230 embeddable and extensible
232 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
233 L<perlguts>, and L<xsubpp>.
237 roll-your-own magic variables (including multiple simultaneous DBM implementations)
239 Described in L<perltie> and L<AnyDBM_File>.
243 subroutines can now be overridden, autoloaded, and prototyped
245 Described in L<perlsub>.
249 arbitrarily nested data structures and anonymous functions
251 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
255 object-oriented programming
257 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
261 compilability into C code or Perl bytecode
263 Described in L<B> and L<B::Bytecode>.
267 support for light-weight processes (threads)
269 Described in L<perlthrtut> and L<Thread>.
273 support for internationalization, localization, and Unicode
275 Described in L<perllocale> and L<utf8>.
281 Described in L<perlsub>.
285 regular expression enhancements
287 Described in L<perlre>, with additional examples in L<perlop>.
291 enhanced debugger and interactive Perl environment,
292 with integrated editor support
294 Described in L<perldebug>.
298 POSIX 1003.1 compliant library
300 Described in L<POSIX>.
304 Okay, that's I<definitely> enough hype.
308 Perl is available for most operating systems, including virtually
309 all Unix-like platforms. See L<perlport/"Supported Platforms">
318 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
320 If your Perl success stories and testimonials may be of help to others
321 who wish to advocate the use of Perl in their applications,
322 or if you wish to simply express your gratitude to Larry and the
323 Perl developers, please write to perl-thanks@perl.org .
327 "@INC" locations of perl libraries
331 a2p awk to perl translator
332 s2p sed to perl translator
334 http://www.perl.com/ the Perl Home Page
335 http://www.perl.com/CPAN the Comprehensive Perl Archive
339 The C<use warnings> pragma (and the B<-w> switch) produces some
342 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
343 diagnostics> pragma automatically turns Perl's normally terse warnings
344 and errors into these longer forms.
346 Compilation errors will tell you the line number of the error, with an
347 indication of the next token or token type that was to be examined.
348 (In a script passed to Perl via B<-e> switches, each
349 B<-e> is counted as one line.)
351 Setuid scripts have additional constraints that can produce error
352 messages such as "Insecure dependency". See L<perlsec>.
354 Did we mention that you should definitely consider using the B<-w>
359 The B<-w> switch is not mandatory.
361 Perl is at the mercy of your machine's definitions of various
362 operations such as type casting, atof(), and floating-point
363 output with sprintf().
365 If your stdio requires a seek or eof between reads and writes on a
366 particular stream, so does Perl. (This doesn't apply to sysread()
369 While none of the built-in data types have any arbitrary size limits
370 (apart from memory size), there are still a few arbitrary limits: a
371 given variable name may not be longer than 251 characters. Line numbers
372 displayed by diagnostics are internally stored as short integers,
373 so they are limited to a maximum of 65535 (higher numbers usually being
374 affected by wraparound).
376 You may mail your bug reports (be sure to include full configuration
377 information as output by the myconfig program in the perl source
378 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
379 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
380 can be used to help mail in a bug report.
382 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
383 don't tell anyone I said that.
387 The Perl motto is "There's more than one way to do it." Divining
388 how many more is left as an exercise to the reader.
390 The three principal virtues of a programmer are Laziness,
391 Impatience, and Hubris. See the Camel Book for why.