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 perlos2 Perl notes for OS/2
128 perlos390 Perl notes for OS/390
129 perlplan9 Perl notes for Plan 9
130 perlqnx Perl notes for QNX
131 perlsolaris Perl notes for Solaris
132 perltru64 Perl notes for Tru64
133 perlvmesa Perl notes for VM/ESA
134 perlvms Perl notes for VMS
135 perlvos Perl notes for Stratus VOS
136 perlwin32 Perl notes for Windows
138 (If you're intending to read these straight through for the first time,
139 the suggested order will tend to reduce the number of forward references.)
141 By default, the manpages listed above are installed in the
142 F</usr/local/man/> directory.
144 Extensive additional documentation for Perl modules is available. The
145 default configuration for perl will place this additional documentation
146 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
147 subdirectory of the Perl library directory). Some of this additional
148 documentation is distributed standard with Perl, but you'll also find
149 documentation for third-party modules there.
151 You should be able to view Perl's documentation with your man(1)
152 program by including the proper directories in the appropriate start-up
153 files, or in the MANPATH environment variable. To find out where the
154 configuration has installed the manpages, type:
158 If the directories have a common stem, such as F</usr/local/man/man1>
159 and F</usr/local/man/man3>, you need only to add that stem
160 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
161 environment variable. If they do not share a stem, you'll have to add
164 If that doesn't work for some reason, you can still use the
165 supplied F<perldoc> script to view module information. You might
166 also look into getting a replacement man program.
168 If something strange has gone wrong with your program and you're not
169 sure where you should look for help, try the B<-w> switch first. It
170 will often point out exactly where the trouble is.
174 Perl is a language optimized for scanning arbitrary
175 text files, extracting information from those text files, and printing
176 reports based on that information. It's also a good language for many
177 system management tasks. The language is intended to be practical
178 (easy to use, efficient, complete) rather than beautiful (tiny,
181 Perl combines (in the author's opinion, anyway) some of the best
182 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
183 those languages should have little difficulty with it. (Language
184 historians will also note some vestiges of B<csh>, Pascal, and even
185 BASIC-PLUS.) Expression syntax corresponds closely to C
186 expression syntax. Unlike most Unix utilities, Perl does not
187 arbitrarily limit the size of your data--if you've got the memory,
188 Perl can slurp in your whole file as a single string. Recursion is of
189 unlimited depth. And the tables used by hashes (sometimes called
190 "associative arrays") grow as necessary to prevent degraded
191 performance. Perl can use sophisticated pattern matching techniques to
192 scan large amounts of data quickly. Although optimized for
193 scanning text, Perl can also deal with binary data, and can make dbm
194 files look like hashes. Setuid Perl scripts are safer than C programs
195 through a dataflow tracing mechanism that prevents many stupid
198 If you have a problem that would ordinarily use B<sed> or B<awk> or
199 B<sh>, but it exceeds their capabilities or must run a little faster,
200 and you don't want to write the silly thing in C, then Perl may be for
201 you. There are also translators to turn your B<sed> and B<awk>
202 scripts into Perl scripts.
204 But wait, there's more...
206 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
207 rewrite that provides the following additional benefits:
213 modularity and reusability using innumerable modules
215 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
219 embeddable and extensible
221 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
222 L<perlguts>, and L<xsubpp>.
226 roll-your-own magic variables (including multiple simultaneous DBM implementations)
228 Described in L<perltie> and L<AnyDBM_File>.
232 subroutines can now be overridden, autoloaded, and prototyped
234 Described in L<perlsub>.
238 arbitrarily nested data structures and anonymous functions
240 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
244 object-oriented programming
246 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
250 compilability into C code or Perl bytecode
252 Described in L<B> and L<B::Bytecode>.
256 support for light-weight processes (threads)
258 Described in L<perlthrtut> and L<Thread>.
262 support for internationalization, localization, and Unicode
264 Described in L<perllocale> and L<utf8>.
270 Described in L<perlsub>.
274 regular expression enhancements
276 Described in L<perlre>, with additional examples in L<perlop>.
280 enhanced debugger and interactive Perl environment,
281 with integrated editor support
283 Described in L<perldebug>.
287 POSIX 1003.1 compliant library
289 Described in L<POSIX>.
293 Okay, that's I<definitely> enough hype.
297 Perl is available for most operating systems, including virtually
298 all Unix-like platforms. See L<perlport/"Supported Platforms">
307 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
309 If your Perl success stories and testimonials may be of help to others
310 who wish to advocate the use of Perl in their applications,
311 or if you wish to simply express your gratitude to Larry and the
312 Perl developers, please write to perl-thanks@perl.org .
316 "@INC" locations of perl libraries
320 a2p awk to perl translator
321 s2p sed to perl translator
323 http://www.perl.com/ the Perl Home Page
324 http://www.perl.com/CPAN the Comprehensive Perl Archive
328 The C<use warnings> pragma (and the B<-w> switch) produces some
331 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
332 diagnostics> pragma automatically turns Perl's normally terse warnings
333 and errors into these longer forms.
335 Compilation errors will tell you the line number of the error, with an
336 indication of the next token or token type that was to be examined.
337 (In a script passed to Perl via B<-e> switches, each
338 B<-e> is counted as one line.)
340 Setuid scripts have additional constraints that can produce error
341 messages such as "Insecure dependency". See L<perlsec>.
343 Did we mention that you should definitely consider using the B<-w>
348 The B<-w> switch is not mandatory.
350 Perl is at the mercy of your machine's definitions of various
351 operations such as type casting, atof(), and floating-point
352 output with sprintf().
354 If your stdio requires a seek or eof between reads and writes on a
355 particular stream, so does Perl. (This doesn't apply to sysread()
358 While none of the built-in data types have any arbitrary size limits
359 (apart from memory size), there are still a few arbitrary limits: a
360 given variable name may not be longer than 251 characters. Line numbers
361 displayed by diagnostics are internally stored as short integers,
362 so they are limited to a maximum of 65535 (higher numbers usually being
363 affected by wraparound).
365 You may mail your bug reports (be sure to include full configuration
366 information as output by the myconfig program in the perl source
367 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
368 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
369 can be used to help mail in a bug report.
371 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
372 don't tell anyone I said that.
376 The Perl motto is "There's more than one way to do it." Divining
377 how many more is left as an exercise to the reader.
379 The three principal virtues of a programmer are Laziness,
380 Impatience, and Hubris. See the Camel Book for why.