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
32 perlopentut Perl open() tutorial
34 perlrequick Perl regular expressions quick start
35 perlretut Perl regular expressions tutorial
37 perlboot Perl OO tutorial for beginners
38 perltoot Perl OO tutorial, part 1
39 perltooc Perl OO tutorial, part 2
40 perlbot Perl OO tricks and examples
42 perlstyle Perl style guide
44 perltrap Perl traps for the unwary
45 perldebtut Perl debugging tutorial
47 perlfaq Perl frequently asked questions
48 perlfaq1 General Questions About Perl
49 perlfaq2 Obtaining and Learning about Perl
50 perlfaq3 Programming Tools
51 perlfaq4 Data Manipulation
52 perlfaq5 Files and Formats
54 perlfaq7 Perl Language Issues
55 perlfaq8 System Interaction
58 =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 perlpod Perl plain old documentation
65 perlrun Perl execution and options
66 perldiag Perl diagnostic messages
67 perllexwarn Perl warnings and their control
68 perldebug Perl debugging
69 perlvar Perl predefined variables
70 perlre Perl regular expressions, the rest of the story
71 perlref Perl references, the rest of the story
74 perltie Perl objects hidden behind simple variables
75 perldbmfilter Perl DBM filters
77 perlipc Perl interprocess communication
78 perlfork Perl fork() information
79 perlnumber Perl number semantics
81 perlthrtut Perl threads tutorial
82 perlothrtut Perl threads tutorial
84 perlport Perl portability guide
85 perllocale Perl locale support
86 perlunicode Perl unicode support
87 perlebcdic Considerations for running Perl on EBCDIC platforms
91 perlmod Perl modules: how they work
92 perlmodlib Perl modules: how to write and use
93 perlmodstyle Perl modules: how to write modules with style
94 perlmodinstall Perl modules: how to install from CPAN
95 perlnewmod Perl modules: preparing a new module for distribution
97 perlutil utilities packaged with the Perl distribution
99 perlcompile Perl compiler suite intro
101 perlfilter Perl source filters
103 =head2 Internals and C Language Interface
105 perlembed Perl ways to embed perl in your C or C++ application
106 perldebguts Perl debugging guts and tips
107 perlxstut Perl XS tutorial
108 perlxs Perl XS application programming interface
109 perlclib Internal replacements for standard C library functions
110 perlguts Perl internal functions for those doing extensions
111 perlcall Perl calling conventions from C
113 perlapi Perl API listing (autogenerated)
114 perlintern Perl internal functions (autogenerated)
115 perliol C API for Perl's implementation of IO in Layers
116 perlapio Perl internal IO abstraction interface
118 perlhack Perl hackers guide
122 perlbook Perl book information
123 perltodo Perl things to do
125 perlhist Perl history records
126 perldelta Perl changes since previous version
127 perl572delta Perl changes in version 5.7.2
128 perl571delta Perl changes in version 5.7.1
129 perl570delta Perl changes in version 5.7.0
130 perl56delta Perl changes in version 5.6
131 perl5005delta Perl changes in version 5.005
132 perl5004delta Perl changes in version 5.004
134 =head2 Platform-Specific
136 perlaix Perl notes for AIX
137 perlamiga Perl notes for AmigaOS
138 perlapollo Perl notes for Apollo DomainOS
139 perlbeos Perl notes for BeOS
140 perlbs2000 Perl notes for POSIX-BC BS2000
141 perlce Perl notes for WinCE
142 perlcygwin Perl notes for Cygwin
143 perldgux Perl notes for DG/UX
144 perldos Perl notes for DOS
145 perlepoc Perl notes for EPOC
146 perlhpux Perl notes for HP-UX
147 perlhurd Perl notes for Hurd
148 perlmachten Perl notes for Power MachTen
149 perlmacos Perl notes for Mac OS (Classic)
150 perlmint Perl notes for MiNT
151 perlmpeix Perl notes for MPE/iX
152 perlnetware Perl notes for NetWare
153 perlos2 Perl notes for OS/2
154 perlos390 Perl notes for OS/390
155 perlplan9 Perl notes for Plan 9
156 perlqnx Perl notes for QNX
157 perlsolaris Perl notes for Solaris
158 perltru64 Perl notes for Tru64
159 perluts Perl notes for UTS
160 perlvmesa Perl notes for VM/ESA
161 perlvms Perl notes for VMS
162 perlvos Perl notes for Stratus VOS
163 perlwin32 Perl notes for Windows
166 By default, the manpages listed above are installed in the
167 F</usr/local/man/> directory.
169 Extensive additional documentation for Perl modules is available. The
170 default configuration for perl will place this additional documentation
171 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
172 subdirectory of the Perl library directory). Some of this additional
173 documentation is distributed standard with Perl, but you'll also find
174 documentation for third-party modules there.
176 You should be able to view Perl's documentation with your man(1)
177 program by including the proper directories in the appropriate start-up
178 files, or in the MANPATH environment variable. To find out where the
179 configuration has installed the manpages, type:
183 If the directories have a common stem, such as F</usr/local/man/man1>
184 and F</usr/local/man/man3>, you need only to add that stem
185 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
186 environment variable. If they do not share a stem, you'll have to add
189 If that doesn't work for some reason, you can still use the
190 supplied F<perldoc> script to view module information. You might
191 also look into getting a replacement man program.
193 If something strange has gone wrong with your program and you're not
194 sure where you should look for help, try the B<-w> switch first. It
195 will often point out exactly where the trouble is.
199 Perl is a language optimized for scanning arbitrary
200 text files, extracting information from those text files, and printing
201 reports based on that information. It's also a good language for many
202 system management tasks. The language is intended to be practical
203 (easy to use, efficient, complete) rather than beautiful (tiny,
206 Perl combines (in the author's opinion, anyway) some of the best
207 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
208 those languages should have little difficulty with it. (Language
209 historians will also note some vestiges of B<csh>, Pascal, and even
210 BASIC-PLUS.) Expression syntax corresponds closely to C
211 expression syntax. Unlike most Unix utilities, Perl does not
212 arbitrarily limit the size of your data--if you've got the memory,
213 Perl can slurp in your whole file as a single string. Recursion is of
214 unlimited depth. And the tables used by hashes (sometimes called
215 "associative arrays") grow as necessary to prevent degraded
216 performance. Perl can use sophisticated pattern matching techniques to
217 scan large amounts of data quickly. Although optimized for
218 scanning text, Perl can also deal with binary data, and can make dbm
219 files look like hashes. Setuid Perl scripts are safer than C programs
220 through a dataflow tracing mechanism that prevents many stupid
223 If you have a problem that would ordinarily use B<sed> or B<awk> or
224 B<sh>, but it exceeds their capabilities or must run a little faster,
225 and you don't want to write the silly thing in C, then Perl may be for
226 you. There are also translators to turn your B<sed> and B<awk>
227 scripts into Perl scripts.
229 But wait, there's more...
231 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
232 rewrite that provides the following additional benefits:
238 modularity and reusability using innumerable modules
240 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
244 embeddable and extensible
246 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
247 L<perlguts>, and L<xsubpp>.
251 roll-your-own magic variables (including multiple simultaneous DBM implementations)
253 Described in L<perltie> and L<AnyDBM_File>.
257 subroutines can now be overridden, autoloaded, and prototyped
259 Described in L<perlsub>.
263 arbitrarily nested data structures and anonymous functions
265 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
269 object-oriented programming
271 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
275 compilability into C code or Perl bytecode
277 Described in L<B> and L<B::Bytecode>.
281 support for light-weight processes (threads)
283 Described in L<perlthrtut> and L<Thread>.
287 support for internationalization, localization, and Unicode
289 Described in L<perllocale> and L<utf8>.
295 Described in L<perlsub>.
299 regular expression enhancements
301 Described in L<perlre>, with additional examples in L<perlop>.
305 enhanced debugger and interactive Perl environment,
306 with integrated editor support
308 Described in L<perldebug>.
312 POSIX 1003.1 compliant library
314 Described in L<POSIX>.
318 Okay, that's I<definitely> enough hype.
322 Perl is available for most operating systems, including virtually
323 all Unix-like platforms. See L<perlport/"Supported Platforms">
332 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
334 If your Perl success stories and testimonials may be of help to others
335 who wish to advocate the use of Perl in their applications,
336 or if you wish to simply express your gratitude to Larry and the
337 Perl developers, please write to perl-thanks@perl.org .
341 "@INC" locations of perl libraries
345 a2p awk to perl translator
346 s2p sed to perl translator
348 http://www.perl.com/ the Perl Home Page
349 http://www.perl.com/CPAN the Comprehensive Perl Archive
353 The C<use warnings> pragma (and the B<-w> switch) produces some
356 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
357 diagnostics> pragma automatically turns Perl's normally terse warnings
358 and errors into these longer forms.
360 Compilation errors will tell you the line number of the error, with an
361 indication of the next token or token type that was to be examined.
362 (In a script passed to Perl via B<-e> switches, each
363 B<-e> is counted as one line.)
365 Setuid scripts have additional constraints that can produce error
366 messages such as "Insecure dependency". See L<perlsec>.
368 Did we mention that you should definitely consider using the B<-w>
373 The B<-w> switch is not mandatory.
375 Perl is at the mercy of your machine's definitions of various
376 operations such as type casting, atof(), and floating-point
377 output with sprintf().
379 If your stdio requires a seek or eof between reads and writes on a
380 particular stream, so does Perl. (This doesn't apply to sysread()
383 While none of the built-in data types have any arbitrary size limits
384 (apart from memory size), there are still a few arbitrary limits: a
385 given variable name may not be longer than 251 characters. Line numbers
386 displayed by diagnostics are internally stored as short integers,
387 so they are limited to a maximum of 65535 (higher numbers usually being
388 affected by wraparound).
390 You may mail your bug reports (be sure to include full configuration
391 information as output by the myconfig program in the perl source
392 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
393 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
394 can be used to help mail in a bug report.
396 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
397 don't tell anyone I said that.
401 The Perl motto is "There's more than one way to do it." Divining
402 how many more is left as an exercise to the reader.
404 The three principal virtues of a programmer are Laziness,
405 Impatience, and Hubris. See the Camel Book for why.