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 perl56delta Perl changes in version 5.6
106 perl5005delta Perl changes in version 5.005
107 perl5004delta Perl changes in version 5.004
109 perlaix Perl notes for AIX
110 perlamiga Perl notes for Amiga
111 perlbs2000 Perl notes for POSIX-BC BS2000
112 perlcygwin Perl notes for Cygwin
113 perldos Perl notes for DOS
114 perlepoc Perl notes for EPOC
115 perlhpux Perl notes for HP-UX
116 perlmachten Perl notes for Power MachTen
117 perlmpeix Perl notes for MPE/iX
118 perlos2 Perl notes for OS/2
119 perlos390 Perl notes for OS/390
120 perlsolaris Perl notes for Solaris
121 perlvmesa Perl notes for VM/ESA
122 perlvms Perl notes for VMS
123 perlvos Perl notes for Stratus VOS
124 perlwin32 Perl notes for Windows
126 (If you're intending to read these straight through for the first time,
127 the suggested order will tend to reduce the number of forward references.)
129 By default, the manpages listed above are installed in the
130 F</usr/local/man/> directory.
132 Extensive additional documentation for Perl modules is available. The
133 default configuration for perl will place this additional documentation
134 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
135 subdirectory of the Perl library directory). Some of this additional
136 documentation is distributed standard with Perl, but you'll also find
137 documentation for third-party modules there.
139 You should be able to view Perl's documentation with your man(1)
140 program by including the proper directories in the appropriate start-up
141 files, or in the MANPATH environment variable. To find out where the
142 configuration has installed the manpages, type:
146 If the directories have a common stem, such as F</usr/local/man/man1>
147 and F</usr/local/man/man3>, you need only to add that stem
148 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
149 environment variable. If they do not share a stem, you'll have to add
152 If that doesn't work for some reason, you can still use the
153 supplied F<perldoc> script to view module information. You might
154 also look into getting a replacement man program.
156 If something strange has gone wrong with your program and you're not
157 sure where you should look for help, try the B<-w> switch first. It
158 will often point out exactly where the trouble is.
162 Perl is a language optimized for scanning arbitrary
163 text files, extracting information from those text files, and printing
164 reports based on that information. It's also a good language for many
165 system management tasks. The language is intended to be practical
166 (easy to use, efficient, complete) rather than beautiful (tiny,
169 Perl combines (in the author's opinion, anyway) some of the best
170 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
171 those languages should have little difficulty with it. (Language
172 historians will also note some vestiges of B<csh>, Pascal, and even
173 BASIC-PLUS.) Expression syntax corresponds closely to C
174 expression syntax. Unlike most Unix utilities, Perl does not
175 arbitrarily limit the size of your data--if you've got the memory,
176 Perl can slurp in your whole file as a single string. Recursion is of
177 unlimited depth. And the tables used by hashes (sometimes called
178 "associative arrays") grow as necessary to prevent degraded
179 performance. Perl can use sophisticated pattern matching techniques to
180 scan large amounts of data quickly. Although optimized for
181 scanning text, Perl can also deal with binary data, and can make dbm
182 files look like hashes. Setuid Perl scripts are safer than C programs
183 through a dataflow tracing mechanism that prevents many stupid
186 If you have a problem that would ordinarily use B<sed> or B<awk> or
187 B<sh>, but it exceeds their capabilities or must run a little faster,
188 and you don't want to write the silly thing in C, then Perl may be for
189 you. There are also translators to turn your B<sed> and B<awk>
190 scripts into Perl scripts.
192 But wait, there's more...
194 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
195 rewrite that provides the following additional benefits:
201 modularity and reusability using innumerable modules
203 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
207 embeddable and extensible
209 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
210 L<perlguts>, and L<xsubpp>.
214 roll-your-own magic variables (including multiple simultaneous DBM implementations)
216 Described in L<perltie> and L<AnyDBM_File>.
220 subroutines can now be overridden, autoloaded, and prototyped
222 Described in L<perlsub>.
226 arbitrarily nested data structures and anonymous functions
228 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
232 object-oriented programming
234 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
238 compilability into C code or Perl bytecode
240 Described in L<B> and L<B::Bytecode>.
244 support for light-weight processes (threads)
246 Described in L<perlthrtut> and L<Thread>.
250 support for internationalization, localization, and Unicode
252 Described in L<perllocale> and L<utf8>.
258 Described in L<perlsub>.
262 regular expression enhancements
264 Described in L<perlre>, with additional examples in L<perlop>.
268 enhanced debugger and interactive Perl environment,
269 with integrated editor support
271 Described in L<perldebug>.
275 POSIX 1003.1 compliant library
277 Described in L<POSIX>.
281 Okay, that's I<definitely> enough hype.
285 Perl is available for most operating systems, including virtually
286 all Unix-like platforms. See L<perlport/"Supported Platforms">
295 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
297 If your Perl success stories and testimonials may be of help to others
298 who wish to advocate the use of Perl in their applications,
299 or if you wish to simply express your gratitude to Larry and the
300 Perl developers, please write to perl-thanks@perl.org .
304 "@INC" locations of perl libraries
308 a2p awk to perl translator
309 s2p sed to perl translator
311 http://www.perl.com/ the Perl Home Page
312 http://www.perl.com/CPAN the Comprehensive Perl Archive
316 The C<use warnings> pragma (and the B<-w> switch) produces some
319 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
320 diagnostics> pragma automatically turns Perl's normally terse warnings
321 and errors into these longer forms.
323 Compilation errors will tell you the line number of the error, with an
324 indication of the next token or token type that was to be examined.
325 (In a script passed to Perl via B<-e> switches, each
326 B<-e> is counted as one line.)
328 Setuid scripts have additional constraints that can produce error
329 messages such as "Insecure dependency". See L<perlsec>.
331 Did we mention that you should definitely consider using the B<-w>
336 The B<-w> switch is not mandatory.
338 Perl is at the mercy of your machine's definitions of various
339 operations such as type casting, atof(), and floating-point
340 output with sprintf().
342 If your stdio requires a seek or eof between reads and writes on a
343 particular stream, so does Perl. (This doesn't apply to sysread()
346 While none of the built-in data types have any arbitrary size limits
347 (apart from memory size), there are still a few arbitrary limits: a
348 given variable name may not be longer than 251 characters. Line numbers
349 displayed by diagnostics are internally stored as short integers,
350 so they are limited to a maximum of 65535 (higher numbers usually being
351 affected by wraparound).
353 You may mail your bug reports (be sure to include full configuration
354 information as output by the myconfig program in the perl source
355 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
356 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
357 can be used to help mail in a bug report.
359 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
360 don't tell anyone I said that.
364 The Perl motto is "There's more than one way to do it." Divining
365 how many more is left as an exercise to the reader.
367 The three principal virtues of a programmer are Laziness,
368 Impatience, and Hubris. See the Camel Book for why.