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