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