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 perltootc 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
60 perlthrtut Perl threads tutorial
62 perlport Perl portability guide
63 perllocale Perl locale support
64 perlunicode Perl unicode support
65 perlebcdic Considerations for running Perl on EBCDIC platforms
69 perlmod Perl modules: how they work
70 perlmodlib Perl modules: how to write and use
71 perlmodinstall Perl modules: how to install from CPAN
72 perlnewmod Perl modules: preparing a new module for distribution
74 perlfaq1 General Questions About Perl
75 perlfaq2 Obtaining and Learning about Perl
76 perlfaq3 Programming Tools
77 perlfaq4 Data Manipulation
78 perlfaq5 Files and Formats
80 perlfaq7 Perl Language Issues
81 perlfaq8 System Interaction
84 perlcompile Perl compiler suite intro
86 perlembed Perl ways to embed perl in your C or C++ application
87 perldebguts Perl debugging guts and tips
88 perlxstut Perl XS tutorial
89 perlxs Perl XS application programming interface
90 perlclib Internal replacements for standard C library functions
91 perlguts Perl internal functions for those doing extensions
92 perlcall Perl calling conventions from C
93 perlutil utilities packaged with the Perl distribution
94 perlfilter Perl source filters
95 perldbmfilter Perl DBM filters
96 perlapi Perl API listing (autogenerated)
97 perlintern Perl internal functions (autogenerated)
98 perliol C API for Perl's implementation of IO in Layers
99 perlapio Perl internal IO abstraction interface
100 perltodo Perl things to do
101 perlhack Perl hackers guide
103 perlhist Perl history records
104 perldelta Perl changes since previous version
105 perl572delta Perl changes in version 5.7.2
106 perl571delta Perl changes in version 5.7.1
107 perl570delta Perl changes in version 5.7.0
108 perl56delta Perl changes in version 5.6
109 perl5005delta Perl changes in version 5.005
110 perl5004delta Perl changes in version 5.004
112 perlaix Perl notes for AIX
113 perlamiga Perl notes for AmigaOS
114 perlapollo Perl notes for Apollo DomainOS
115 perlbeos Perl notes for BeOS
116 perlbs2000 Perl notes for POSIX-BC BS2000
117 perlcygwin Perl notes for Cygwin
118 perldgux Perl notes for DG/UX
119 perldos Perl notes for DOS
120 perlepoc Perl notes for EPOC
121 perlhpux Perl notes for HP-UX
122 perlhurd Perl notes for Hurd
123 perlmachten Perl notes for Power MachTen
124 perlmacos Perl notes for Mac OS (Classic)
125 perlmint Perl notes for MiNT
126 perlmpeix Perl notes for MPE/iX
127 perlnetware Perl notes for NetWare
128 perlos2 Perl notes for OS/2
129 perlos390 Perl notes for OS/390
130 perlplan9 Perl notes for Plan 9
131 perlqnx Perl notes for QNX
132 perlsolaris Perl notes for Solaris
133 perltru64 Perl notes for Tru64
134 perluts Perl notes for UTS
135 perlvmesa Perl notes for VM/ESA
136 perlvms Perl notes for VMS
137 perlvos Perl notes for Stratus VOS
138 perlwin32 Perl notes for Windows
140 (If you're intending to read these straight through for the first time,
141 the suggested order will tend to reduce the number of forward references.)
143 By default, the manpages listed above are installed in the
144 F</usr/local/man/> directory.
146 Extensive additional documentation for Perl modules is available. The
147 default configuration for perl will place this additional documentation
148 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
149 subdirectory of the Perl library directory). Some of this additional
150 documentation is distributed standard with Perl, but you'll also find
151 documentation for third-party modules there.
153 You should be able to view Perl's documentation with your man(1)
154 program by including the proper directories in the appropriate start-up
155 files, or in the MANPATH environment variable. To find out where the
156 configuration has installed the manpages, type:
160 If the directories have a common stem, such as F</usr/local/man/man1>
161 and F</usr/local/man/man3>, you need only to add that stem
162 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
163 environment variable. If they do not share a stem, you'll have to add
166 If that doesn't work for some reason, you can still use the
167 supplied F<perldoc> script to view module information. You might
168 also look into getting a replacement man program.
170 If something strange has gone wrong with your program and you're not
171 sure where you should look for help, try the B<-w> switch first. It
172 will often point out exactly where the trouble is.
176 Perl is a language optimized for scanning arbitrary
177 text files, extracting information from those text files, and printing
178 reports based on that information. It's also a good language for many
179 system management tasks. The language is intended to be practical
180 (easy to use, efficient, complete) rather than beautiful (tiny,
183 Perl combines (in the author's opinion, anyway) some of the best
184 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
185 those languages should have little difficulty with it. (Language
186 historians will also note some vestiges of B<csh>, Pascal, and even
187 BASIC-PLUS.) Expression syntax corresponds closely to C
188 expression syntax. Unlike most Unix utilities, Perl does not
189 arbitrarily limit the size of your data--if you've got the memory,
190 Perl can slurp in your whole file as a single string. Recursion is of
191 unlimited depth. And the tables used by hashes (sometimes called
192 "associative arrays") grow as necessary to prevent degraded
193 performance. Perl can use sophisticated pattern matching techniques to
194 scan large amounts of data quickly. Although optimized for
195 scanning text, Perl can also deal with binary data, and can make dbm
196 files look like hashes. Setuid Perl scripts are safer than C programs
197 through a dataflow tracing mechanism that prevents many stupid
200 If you have a problem that would ordinarily use B<sed> or B<awk> or
201 B<sh>, but it exceeds their capabilities or must run a little faster,
202 and you don't want to write the silly thing in C, then Perl may be for
203 you. There are also translators to turn your B<sed> and B<awk>
204 scripts into Perl scripts.
206 But wait, there's more...
208 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
209 rewrite that provides the following additional benefits:
215 modularity and reusability using innumerable modules
217 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
221 embeddable and extensible
223 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
224 L<perlguts>, and L<xsubpp>.
228 roll-your-own magic variables (including multiple simultaneous DBM implementations)
230 Described in L<perltie> and L<AnyDBM_File>.
234 subroutines can now be overridden, autoloaded, and prototyped
236 Described in L<perlsub>.
240 arbitrarily nested data structures and anonymous functions
242 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
246 object-oriented programming
248 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
252 compilability into C code or Perl bytecode
254 Described in L<B> and L<B::Bytecode>.
258 support for light-weight processes (threads)
260 Described in L<perlthrtut> and L<Thread>.
264 support for internationalization, localization, and Unicode
266 Described in L<perllocale> and L<utf8>.
272 Described in L<perlsub>.
276 regular expression enhancements
278 Described in L<perlre>, with additional examples in L<perlop>.
282 enhanced debugger and interactive Perl environment,
283 with integrated editor support
285 Described in L<perldebug>.
289 POSIX 1003.1 compliant library
291 Described in L<POSIX>.
295 Okay, that's I<definitely> enough hype.
299 Perl is available for most operating systems, including virtually
300 all Unix-like platforms. See L<perlport/"Supported Platforms">
309 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
311 If your Perl success stories and testimonials may be of help to others
312 who wish to advocate the use of Perl in their applications,
313 or if you wish to simply express your gratitude to Larry and the
314 Perl developers, please write to perl-thanks@perl.org .
318 "@INC" locations of perl libraries
322 a2p awk to perl translator
323 s2p sed to perl translator
325 http://www.perl.com/ the Perl Home Page
326 http://www.perl.com/CPAN the Comprehensive Perl Archive
330 The C<use warnings> pragma (and the B<-w> switch) produces some
333 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
334 diagnostics> pragma automatically turns Perl's normally terse warnings
335 and errors into these longer forms.
337 Compilation errors will tell you the line number of the error, with an
338 indication of the next token or token type that was to be examined.
339 (In a script passed to Perl via B<-e> switches, each
340 B<-e> is counted as one line.)
342 Setuid scripts have additional constraints that can produce error
343 messages such as "Insecure dependency". See L<perlsec>.
345 Did we mention that you should definitely consider using the B<-w>
350 The B<-w> switch is not mandatory.
352 Perl is at the mercy of your machine's definitions of various
353 operations such as type casting, atof(), and floating-point
354 output with sprintf().
356 If your stdio requires a seek or eof between reads and writes on a
357 particular stream, so does Perl. (This doesn't apply to sysread()
360 While none of the built-in data types have any arbitrary size limits
361 (apart from memory size), there are still a few arbitrary limits: a
362 given variable name may not be longer than 251 characters. Line numbers
363 displayed by diagnostics are internally stored as short integers,
364 so they are limited to a maximum of 65535 (higher numbers usually being
365 affected by wraparound).
367 You may mail your bug reports (be sure to include full configuration
368 information as output by the myconfig program in the perl source
369 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
370 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
371 can be used to help mail in a bug report.
373 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
374 don't tell anyone I said that.
378 The Perl motto is "There's more than one way to do it." Divining
379 how many more is left as an exercise to the reader.
381 The three principal virtues of a programmer are Laziness,
382 Impatience, and Hubris. See the Camel Book for why.